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139. One-year evaluation: Is there effect of 8 weeks supervised progressive resistance training after unicompartmental knee arthroplasty?
Peter Bo Jørgensen, Søren Bie Bogh, Signe Kierkegaard, Henrik Sørensen, Kjeld Søballe, Inger Mechlenburg
Orthopaedic Research, Aarhus University Hospital; Center for Quality, Region of Southen Denmark; Sports Science, Aarhus University

Background: Muscle atrophy and decreased muscle strength is documented in early stages of knee osteoarthritis and increases with progression. Within the first weeks after Unicompartmental Knee Arthroplasty (UKA) an additional decrease in muscle strength is found. That is the rationale for early initiated resistance training.
Purpose / Aim of Study: To evaluate if there is effect of 8 weeks progressive resistance training (PRT) after UKA assessed 1 year postoperative.
Materials and Methods: 53 patients (26 males), median age 66 years, scheduled for UKA were randomized to either 8 weeks supervised PRT (n=29) or 8 weeks standard home exercise (HE) program (n=24). PRT was initiated within the first week after UKA and performed 2/week for 8 weeks in training machines. Preoperative assessment, 2-months and 1-year follow-up were performed for leg press power, asymmetry in gait, walking speed and Knee injury and Osteoarthritis Outcome Score (KOOS).
Findings / Results: 22 PRT and 18 HE-patients (73%) completed 1-year follow-up and patients in the PRT group participated in mean 11 of 16 training sessions. Leg press power increased from baseline to 1-year follow up (PRT: 29% and HE: 30%, p<0.04 in both groups) and asymmetry was minimally changed (PRT: 0,14% and HE: 0,29%) with no between-group difference (p>0.53 and power >0.89). Walking speed (PRT: 16% and HE: 15%), KOOS symptoms (PRT: 21 point and HE: 15 point), KOOS pain (PRT: 38 point and HE: 32 point), KOOS ADL (PRT: 29 point HE: 28 point) KOOS sport (PRT: 33 point and HE: 42 point), KOOS QoL (PRT: 39 point and HE: 32 point) increased in both groups with no between-group difference (p>0.42).
Conclusions: We found no additional effect of an 8-week PRT program compared to HE in this patient group when assessed one year after surgery.

140. Is gait velocity and gait quality associated with hip muscle strength in hip osteoarthritis patients scheduled for total hip arthroplasty?
Signe Rosenlund, Dennis Brandborg Nielsen, Søren Overgaard, Carsten Jensen, Anders Holsgaard-Larsen
Department of Orthopedic Surgery and Traumatology and Orthopaedic Research Unit, Department of Ortho, Køge Hospital and Odense University Hospital; Orthopaedic Research Unit, Department of Orthopaedic Surgery and Traumatology, Odense University Hospital; Orthopaedic Research Unit, Department of Orthopaedic Surgery and Traumatology and Institute of Clini, Odense University Hospital and University of Southern Denmark

Background: Association between lower extremity muscle strength and gait velocity has been documented in healthy elderly individuals but not in patients with end- stage hip osteoarthritis (OA). Three- dimensional (3D) gait analysis help identify gait pathology. But the complexity and amount of data collected during gait analysis lead to challenges when interpreting these. Gait Deviation Index (GDI) summarizes the lower limb kinematic data and describes 98% of the variation in gait.
Purpose / Aim of Study: The aim of this study was to investigate associations between hip muscle strength, gait velocity, and GDI in patients with end- stage hip OA.
Materials and Methods: A cohort of 20 consecutive patients all with unilateral end-stage hip OA scheduled for THA (5 women and 15 men; age 61± 5.8 years; BMI 28.1 ± 3.4 (mean ± SD)). All completed 3D gait analysis and performed isometric maximal voluntary hip muscle strength (MVC) tests (hip-flexion, -abduction and - extension). A GDI of 100 indicates no gait pathology and a 10 point change represents 1 SD from the reference group. Linear regression analysis were used to determine coefficient of determination using GDI or gait velocity as dependent variables and hip MVC as the independent variables.
Findings / Results: A significant association (R2 = 0.43; p=0.03) between gait velocity and hip MVC was observed using multiple linear regression. Furthermore, simple regression analysis revealed a moderate association (R2 = 0.23; p=0.03) between hip abduction and gait velocity. However, no association between GDI and hip MVC was found.
Conclusions: The present study confirms an association between hip MVC and gait velocity for OA patients scheduled for THA. However, no association between hip MVC and gait quality was shown. The present data indicate that rehabilitation aimed at improving hip muscle strength would be effective.

141. Objectively measured physical activity – reference data obtained from a Dutch population with a three-axial accelerometer
Signe Kierkegaard, Inger Mechlenburg, Bernd Grimm, Ide Heyligers, Rachel Senden
Orthopaedic Research, Aarhus University Hospital, Denmark; Department Orthopaedic Surgery & Traumatology, Atrium Medical Center, Heerlen, The Netherlands

Background: Self-reported physical activity (PA) is often under/overestimated and influenced by patient satisfaction and pain. Thus, PA after surgery or rehabilitation should be measured objectively, which is easily done using ambulant accelerometer based activity monitoring (AM). However a reference database of AM parameters is currently lacking.
Purpose / Aim of Study: To collect reference data of objectively measured PA.
Materials and Methods: 59 Dutch healthy subjects, (37 females) median aged 47.5 (21-66) years with no restrictions in mobility were included. A three-axial accelerometer was attached during waking hours to the participants’ lateral thigh for four consecutive days. Data was analysed using previously validated algorithms in MatLab 7.10.0 ®. Median values of the four days were calculated and the results were stratified into age groups of decades, 20-29 (30-39) 40-49 (50-59) and 60-69.
Findings / Results: Mean measurement time was 13.5 ±1.5 hours per day. Subjects were sitting median 64 (53) 59 (59) 57 %, standing 22 (32) 29 (26) 31 %, walking 9 (14) 13 (11) 12 % and biking 0.5 (0.4) 0.02 (0.4) 0.5 % of the day. Subjects walked on average 5217 (8447) 7666 (8474) 7030 steps per day and performed mean 43 (63) 50 (45) 47 sit to stand transfers a day. There was a tendency towards the youngest group sitting more and standing and walking less than the older groups, but no statistically significant differences were found between the age groups.
Conclusions: The present data may serve as initial values for a reference database. However, the results are affected by a large variation in PA and a small age range, which might explain the lack of significant differences between age groups. A larger reference database need to be created where effects of subject characteristics on PA can be investigated and where people above 66 years are included as well.

142. Validation of intraoperative reported angle measurements in periactabular osteotomy
Sepp De Raedt, Inger Mechlenburg, Maiken Stilling, Marleen de Bruijne, Lone Rømer, Kjeld Søballe
Orthopaedic Research Unit, Aarhus University Hospital; BIGR/DIKU, Erasmus MC Rotterdam/University of Copenhagen; Department of Radiology, Aarhus University Hospital

Background: Periactabular osteotomy (PAO) has become the treatment of choice for patients with developmental hip dysplasia. However, it is a technically demanding procedure and achieving an optimal correction can be difficult due to the lack of three-dimensional (3D) feedback. The biomechanical guidance system (BGS) provides the surgeon with live 3D feedback.
Purpose / Aim of Study: To validate measurements obtained with the BGS against manual measurements.
Materials and Methods: Patients underwent pre- and post-operative CT imaging. Manual center-edge (CE), acetabular index (AI), acetabular anteversion (AcAV), posterior acetabular sector (PASA) and anterior acetabular sector (AASA) angle measurements were performed. The lunate surface was manually delineated and surgical planning was performed. Initial automatic angle measurements were recorded. After the acetabular fragment was repositioned and fixated, the BGS was used to obtain the final angle measurements. The difference between the manual and the BGS reported angle measurements were analyzed by statistical analysis. We report the concordance correlation coefficient (CCC), average difference, and the 95% limits of agreement (LOA).
Findings / Results: Initial results for the first five patients included were: CE angle: CCC: 0.93, Avg. Diff.: 0.40, 95% LOA: -4.52;5.31. AI angle: CCC: 0.98, Avg. Diff.: 0.17, 95% LOA: -2.59;2.94. AcAV angle: CCC: 0.96, Avg. Diff.: 0.68, 95% LOA: -2.30;3.66. PASA angle: CCC: 0.92, Avg. Diff.: 0.82, 95% LOA: -4.26;5.90. AASA angle: CCC: 0.98, Avg. Diff.: 0.03, 95% LOA: -4.63;4.69.
Conclusions: Initial results show a good agreement between manual and BGS reported angles and are within the variation expected from intra-rater variability. With further development and validation, the system may become a valuable tool to help the surgeon achieve the optimal correction for each patient.

143. Safety of Vitamin E infused high wall liners for routine use in primary THA: Single center, short term follow-up of 767 cases
Nanna Sillesen Hylleholt, Christopher Barr J., Peter Gebuhr, Henrik Malchau, Henrik Husted, Troelsen Anders
Department of Orthopedics Copenhagen University Hospital Hvidovre, Hvidovre Hospital; Harris Orthopaedic Laboratory, department of orthopedics, Massachusetts General Hospital, Harvard Medical School

Background: Vitamin E infused highly crosslinked polyethylene liners (VEPE) offer the potential for reduced wear and osteolysis. The extended liners, including the high wall type, leaving parts of the polyethylene uncovered, have been hypothesized to result in increased wear and the potential for liner fracture. Introduction of new implants should be monitored closely to capture any signs of compromising patient safety.
Purpose / Aim of Study: The aim of this study was to determine the short-term safety profile of high wall VEPE for primary total hip replacement (THA), focusing on liner related complications.
Materials and Methods: We included 767 consecutive THAs operated from July 2010 to March 2013 with use of a high wall VEPE liner (E1, Biomet). The preferred components used were an uncemented cup (Exceed ABT, Biomet (100 %) and an uncemented stem (Bimetric, Biomet (98 %)). Majority of heads were size 36mm (67 %) and 32mm (32 %).The data collected included demographics, implant data, complications, reoperations, and deaths. Acetabular cup position was measured using Martell Hip Analysis Suite in a subgroup of 407 THAs. Length of follow- up was 1.1-3.8 years.
Findings / Results: There were no revisions due to liner failure. Revisions included 5 open reductions, 11 soft-tissue revisions for infection, 28 isolated stem revisions (periprosthetic fractures), 2 isolated cup revisions, and 7 combined cup and stem revisions. The subgroup with cup position measurements showed 77% were in the combined acceptable zone of cup abduction (30-55°) and version (5-35°).
Conclusions: Early follow-up of routine use of VEPE high wall liners for primary THA have not shown any liner associated complications or revisions. Continued monitoring of new materials are important to capture any signs of compromised patient safety.

144. Acetabular dysplasia increases risk for malpositioning of the acetabular component in Total Hip Arthroplasty (THA)
Kirill Gromov, Meridith Greene, Christopher Barr, Peter Gebuhr, Henrik Malchau, Anders Troelsen
Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre; Harris Orthopaedic Laboratory, Massachusetts General Hospital

Background: Persistent acetabular dysplasia (AD) following periacetabular osteotomy (PAO) has been hypothesized to increase the risk for malpositioning of the acetabular component that may subsequently lead to higher rates of wear, dislocation and impingement.
Purpose / Aim of Study: The purpose of this study was to investigate whether AD is an independent risk factor for cup malpositioning.
Materials and Methods: 839 primary THA patients, with pre and postoperative pelvic radiographs, from 16 centers in the USA and Europe are enrolled into a prospective 10year outcome study. All patients were operated using an uncemented Biomet® cup and a Biomet® stem of surgeons’ choice. Patient demographics and surgical parameters were recorded. AD was assessed by measuring lateral center edge (LCE) angle and defined as LCE<25°. Cup positioning was determined on postoperative AP pelvic images using Martell Hip Analysis Suite. Acceptable ranges were defined as 30-45° abduction and 5-25°version. Multivariate logistic regression analysis was performed to calculate adjusted risk for cup malpositioning.
Findings / Results: 504 (60%) acetabular cups were within the abduction range, 608 (73%) were within the anteversion range, and 377 (45%) were within the range of both. Surgical approach, presence of AD, and JSW>0 independently predicted malposition of the acetabular component. Surgical approach (direct lateral vs posterolateral), JSW>0, and AD resulted in a 2.00 (1.24-3.22), 1.51 (1.09-2.01) and 1.49 (1.11-1.99) increase in risk for malposition of the acetabular component, respectively.
Conclusions: Presence of AD, defined as an LCE angle <25°, is an independent risk factor for malposition of the acetabular component during primary THA. Skin approach and radiological grade of OA were also independently correlated with malpositioned cups.

145. High frequency of cystic pseudotumors in large-head metal-on-metal total hip arthroplasty at 5-7 years follow-up.
Mette Holm Hjorth , Niels Egund, Inger Mechlenburg, Stig Storgaard Jakobsen, Kjeld Søballe, Maiken Stilling
Department of Orthopaedics , Aarhus University Hospital ; Department of Radiology, Aarhus University Hospital

Background: Large-head metal-on-metal (MoM) total hip arthroplasty (THA) has been associated with pseudotumor formation and high revision rates.
Purpose / Aim of Study: To investigate the frequency of pseudotumors, metal-ion concentrations and radiographic and clinical outcome in patients with MoM THA.
Materials and Methods: A consecutively included series of 41 patients/49hips (31 males) with a mean age of 52 (28-68) years, participated in a 5-7- year follow-up study of their large-headMoM THA (M2a Magnum, Biomet). Patients were evaluated with magnetic resonance imaging (MRI), serum metal-ion concentrations, conventional radiographs, and clinical outcome measures of Harris Hip Score (HHS) and Oxford Hip Score (OHS).
Findings / Results: 18 of 47 hips (38%) had MRI-verified pseudotumors, all cystic, with a mean dimension of 1.1 x 2.6 x 0.4 cm. Acetabular cup anteversion was mean 28+5° in patients with a pseudotumor and mean 24 +7° in patients without a pseudotumor (p=0.009). Serum metal-ion concentrations, acetabular cup inclination and clinical outcome measures of HHS and OHS were similar between patients with and without a pseudotumor.
Conclusions: At 5-7 year after surgery, MRI-verified cystic pseudotumors were frequently observed in large-head MoM THA, without relation to clinical symptoms and metal-ion concentrations but with relation to cup- anteversion. The clinical relevance and the natural history of cystic pseudotumors in asymptomatic patients remain unknown; hence, we will continue to monitor these patients regularly.

146. Radiologic and histologic appearance of metal-bone interphase in failed tibial component in total knee arthroplasty. A retrieval study.
Tue Smith Jørgensen, Thomas Lind, Henrik Schrøder, Eva Balslev
Ortopædkirurgisk afdeling, Herlev hospital; ortopædkirurgisk afdeling, Gentofte Hospital; patolgisk afdeling, Herlev hospital

Background: Little information is available considering lack of ingrowth of bone into the porous coated knee prosthesis. Ususally described as fibrous tissue in the bone-metal interphase. Our five retrieval cases showed macro- and microscopic signs of hyaline cartilage in the tibia bone-metal interphase.
Purpose / Aim of Study: We want to describe the histological findings in the tibia bone-metal interphase, and correlate this to the radiologic and scintigraphic findings in connection with suspected aseptic loosening especially on the tibia side.
Materials and Methods: The five patients all underwent primary knee surgery during the period 2004- 2006 with uncemented knee prosthesis of porous coated type (PFC). Four with osteoarthritis and one with rheumatoid arthritis. They were chosen for secondary operation because of pain and suspected loose tibia component. At revision the resected bone slice was send for pathological examination. Pre- and post op. x-rays are measured to evaluate the amount of primarily resected bone. Pubmed Keywords: uncemented, TKA, failure, cementless, press fit condylar tibia component, tantalum knee, bone ingrowth. Bone metal interphase
Findings / Results: In all the samples, which surface turned against the prosthesis we found hyaline cartilage-like tissue. No articles were found, regarding hyaline cartilage in the bone metal interphase, during our Pubmed search. Only histological confirmed fibrous tissue were described. We discuss some considerations regarding level of resection, possible diagnostic features and the radiological appearance.
Conclusions: One of the possible modes of failure of uncemented knee prosthesis could be the interference of cartilage formating cells, occluding the interphase, before the osseointegration can take place. In some of the specimens, small areas of ingrowth around the tibial peg, was observed.

147. Hip arthroplasty with the Primoris® stem – Bone remodelling around a short femoral neck stem
Janus Duus Christiansen, Lauersen Mogens Berg, Gordon Blunn, Poul Torben Nielsen
Northern Ortopaedic Division, Aalborg University Hospital; , University College London, RNOHT, Stanmore, United Kingdom

Background: Total hip arthroplasty gives immediate pain relief and restoration of mobility in patients with end stage osteoarthritis. If the patient returns for revision and after two or three revisions bone stock left for reimplantation will be compromised. The Primoris ® stem is a development of earlier conceived bone-saving prosthesis in order to preserve bone stock.
Purpose / Aim of Study: This study includes postoperative changes in BMD in the proximal femur and evaluation of bone stock preservation at 1 year follow up (FU) in patients with the Primoris ® stem.
Materials and Methods: : A prospective cohort study of 52 patients scheduled for surgery with the femoral neck-preserving Primoris ® stem was carried out. Patients were studied with DEXA-scans, RSA- analysis, Harris hip score, UCLA activity score, WOMAC, EQ5D health questionnaire and Oxford Hip scores. Results from DEXA-scanner were measured in 3 specific regions of interest (ROI) - the regions of calcar (ROC), trochanter minor (ROT) and a diaphysial reference (ROD). Postoperative BMD results from day one, 6 months and 12 months were analysed.
Findings / Results: 3 patients were excluded, leaving 49 patients for BMD-analysis. A slightly significant decrease was found at 6 months FU compared to day one in ROC and ROT. There was no significant difference at 12 months FU compared to day one. A non significant gain of BMD was found at 12 months FU compared to 6 months FU.
Conclusions: As to bone preservation the results are encouraging. Later follow up will be performed to evaluate if the bone stock remains. If the proximal femoral bone stock is preserved and diaphysis is not compromised then the potential for successful future revision is maximized.

148. Prevalence of kidney dysfunction at elective total hip arthroplasty operations.
Helene Berg-Nielsen, Morten Boye Petersen, Mette Brimnes Damholt, Søren Solgaard
Lægevidenskab, Københavns Universitet; Ortopædkirurgisk afdeling, Gentofte Hospital; Nefrologisk afdeling, Rigshospitalet

Background: Previous studies in other surgical specialties have shown a clear correlation between even small increases in plasma Creatinine (pCr), development of Acute Kidney Injury (AKI) and increased long-term mortality.
Purpose / Aim of Study: To investigate pre-operative kidney function as estimated glomerular filtration rate (eGFR) and the occurrence of AKI amongst a population undergoing elective hip arthroplasty.
Materials and Methods: The study is a single-center, retrospective, register-based cohort study including all primary, elective, total hip replacement surgeries (THA) carried out in Hørsholm and Gentofte hospitals from Jan. 2000 to Dec. 2012. Presence of AKI and eGFR was evaluated on basis of international KDIGO criteria.
Findings / Results: 5687 operations were performed in 4909 patients. Only the first THA for each person was considered. Pre-operative pCr (< 3 months pre operation) could be obtained for 3328 persons (68 %); 2014 females and 1314 males; age 68,6 ± 10,1 years (mean±SD). In this population kidney function was moderately to severely decreased (eGFR < 59 ml/min) (CKD 3-5) in 11,9 % of the patients. Both pre- and postoperative pCr (one value within three days after operation) could be obtained in 2388 persons (49% of patients). Development of AKI based on an increase in pCr was seen in 35 persons (1,5 %) in this population.
Conclusions: Decreased kidney function seems to be prevalent in an elective orthopedic population. Data is not sufficient to evaluate whether AKI is prevalent in this population, but 1,5 % of the patients, who could be evaluated, meet criteria for development of acute kidney injury. If we are to determine the impact of AKI in orthopedic patients, measuring pCr should be part of the standard postoperative observation. Further studies are ongoing.

149. Average cyst volume per cyst-patient decreases over a 10-year period after periacetabular osteotomy
Inger Mechlenburg, Jens R. Nyengaard, John Gelineck, Kjeld Søballe
Orthopaedic Research, Aarhus University Hospital; Stereology and Electron Microscopy Laboratory and CSGB , Aarhus University; Department of Radiology, Aarhus University Hospital

Background: Bone cysts in patients with hip dysplasia are the results of degeneration or defects of the cartilage and local elevated stress in the subchondral bone.
Purpose / Aim of Study: To examine how many patients have acetabular or femoral head cysts and investigate whether the volume of cysts change after PAO.
Materials and Methods: Magnetic resonance imaging (MRI) was performed in a series of 26 consecutively included patients before periacetabular osteotomy (PAO) and 1, 2½ and 10 years after. 26 patients had MRI preoperatively, 25 returned for MRI at 1 year, 21 at 2½ years and 18 at 10 year follow up. The number of cysts was noted and the total cyst volume in each patient was estimated with a design-unbiased stereology. The Hip disability and Osteoarthritis Outcome Score (HOOS) was collected 4 and 10 years after PAO.
Findings / Results: Preoperative, 12 patients had acetabular or femoral head cysts (22 cysts), 1 year postoperative, 15 patients had cysts (23 cysts), 2½ years postoperative, 15 patients had cysts (18 cysts) and 10 years after PAO 9 patients had cyst (9 cysts). Mean total acetabular cyst volume per cyst-patient at the time of MRI was: 3.44 + 6.71 cm3 (1.96 + 3.97 cm3) 0.96 + 1.70 cm3 (0.43 + 0.26 cm3) (p=0.04). All acetabular cysts were located anterolaterally in the acetabulum except for one that was posterolateral. At 4 and 10 years, the mean subscores for HOOS were Pain 75/79, Symptoms 75/73, ADL 83/85, Sport/recreation 63/68 and Quality Of Life 62/61.
Conclusions: The mean total cyst volume per cyst- patient decreased significantly over a 10-year period after PAO. We believe this is a result of decreased local stress in the subchondral bone after PAO which also indicates that redirection of the acetabulum reduces the risk of progression of osteoarthritis in the operated hip.

150. Outcome of Two-stage revision of chronic infections in hip joint replacement in Denmark 2003-2008.
Jeppe Lange, Alma B. Pedersen, Anders Troelsen, Kjeld Søballe
Lundbeckfoundation Centre for Fast-track Hip and Knee Surgery, Tage-Hansens Gade 2, 8000 Aarhus, Den, Department of Orthopaedic Surgery, Aarhus University Hospital, Tage-Hansens Gade 2, 8000 Aarhus, Den; Department of Clinical Epidemiology, Aarhus University Hospital, Olof Palmes Allé 43-45, 8200 Aarhus, Denmark; Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre, Kettegaard Allé 30, 2650 Hvidovre Denmark

Background: Chronic infections in a hip joint replacement (CIHJR) is believed to occur in less than ½% of patients. Currently, the gold-standard treatment for CIHJR is a two-stage revision. Little is known on the overall status of this treatment in Denmark (DK).
Purpose / Aim of Study: We aimed to investigate the outcome of two- stage revision in DK.
Materials and Methods: We identified patients in the Danish National Patient Registry from 2003-2008 in 11 orthopaedic departments with a primary and secondary ICD10 discharge diagnosis of T84.5 in combination with a hip joint specific procedure code or a hip joint specific infectious surgical procedure code independently of ICD10 code. Patients with a total hip-, hemi hip- or resurfacing hip arthroplasty, a diagnosis of deep infection adapted from the American Musculoskeletal Infection Society and more than 6 weeks since latest surgery to the hip joint were defined as having CIHJR (n=114).
Findings / Results: Two-stage revision of the index CIHJR was performed in 80 of 114 (70%) patients. Mean age in the two-stage cohort was 68 years (range 36-92), 35 (44%) were female and 73 (91%) had ASA 1 or 2. 15 (19%) of the index CIHJR were revision prosthesis and 25 (31%) presented with a chronic fistula.49 (61%) had spacer in the interim period. At removal of index CIHJR, Kamme- biopsies were culture negative in 23 (29%). 58 (73%) had cementless stem and 60 (75%) had cementless cup implanted at 2. revision. Median follow up was 7.4 years (range 4-11). 60 (75%) were not revised due to re-infection. However, of these 60, 15 (25%) were revised due to aseptic causes. 28 (35%) died during follow up.
Conclusions: Two-stage revision in DK appears to give overall acceptable results. However, hip surgeons must keep in mind that 30% of all chronic infections are not treated with this surgical procedure.

151. No dislocations after primary total hip arthroplasty with the AVANTAGE® dual mobility cup in Garden Type 3/4 hip fracture patients with dementia: A retrospective study of 26 procedures.
Anders Elneff Graversen, Mathias Bjerring Ho, Stig Storgaard Jakobsen, Andrey Kovalev, Pia Kjær Kristensen, Theis Muncholm Thillemann
Department of Orthopedic Surgery, Hospitalsenheden Horsens; Department of Clinical Epidemiology, Aarhus University Hospital

Background: The dual mobility cup offers intra-joint stability through a large diameter mobile liner and large cup-coverage. The dual mobility cup has therefore been proposed as a treatment option in patients a high risk of luxation e.g. dementia, psychiatric disease, neuromuscular disease, and special revision cases. However, the clinical documentation is still sparse and dislocation rates, reoperation rates and 30 days mortality in patients with Garden type 3/4 femoral neck fracture and dementia is unknown.
Purpose / Aim of Study: The aim of this study was to evaluate the dislocation rates, reoperation rates and 30 day mortality following THA with AVANTAGE® dual mobility cup in patients with Garden type 3/4 femoral neck fracture and dementia.
Materials and Methods: From 2010 to 2014 we retrospectively identified 26 procedures (25 patients) with the AVANTAGE® dual mobility cup in patients with Garden type 3/4 femoral neck fractures and dementia. Outcome measures were collected by systematic review of the national medical records The primary outcome was dislocation. Secondary outcomes were revision surgery, 30 days mortality, surgical delay and in hospital stay. Furthermore, the cup inclination was determined.
Findings / Results: Median time of follow-up was 7,9 (0,4-40,4) months. None of the patients experienced dislocation or received revision surgery. The 30-days mortality rate was 19,2% (5/26). Mean surgical delay was 30,6 hours (CI 95%: 21,6-39,6) and mean in hospital stay was 7 days (CI 95%: 5,2-8,5).
Conclusions: THA with the dual-mobility cup seems favourable in the treatment of patients with a displaced femoral neck fracture and dementia. Correct placement of the cup is pivotal and technically demanding why challenges regarding the logistics can be encountered since time to surgery is known to affect the mortality negatively.

152. DHAR – 1-year results of Hip Arthroscopy in Adolescents
Bent Lund, Søren Winge, Otto Kraemer, Torsten Grønbech Nielsen, Martin Carøe Lind
Dept. of Orthopedics, Horsens Regional Hospital; Copenhagen Private Hospital, ; Dept. of Orthopaedics, Arthroscopic Center of Amager; Orthopedics, Aarhus University Hospital

Background: CAM and Pincer FAI leads to early on-set of degenerative arthritis and even in the very young this morphology and symptomatology is seen. Studies have shown that FAI can be seen radiologically from the early teenage years and it seems that it is caused by physeal injury. Treatment of symptomatic FAI is important to prevent the early on-set of osteoarthritis.
Purpose / Aim of Study: We present registry data of young FAI patients from DHAR and the early outcomes based on PROM's (Patients Related Outcome Measures).
Materials and Methods: Radiology data, indications and operative procedures are registered. These are CE- angle, Alfa angle, labral and cartilage surgery, CAM and Pincer surgery, OR- and traction time. (PROM) preoperatively and 1year follow-up. PROM'S used: pain at rest, pain at activity, iHOT12, HAGOS. We present a sub-group of < 19 year patients from the registry.
Findings / Results: Data from 18 patients < 19 year and 1 year PROM data. 5 males and 13 females. Mean OR-time 75 minutes and mean traction time 57 minutes. Mean CE-angle 32,5 (26-57) and mean Alfa-angle 62 (43-87). Cartilage damage was seen in 13 patients and ICRS classification grade II in 7 patients and III in 6 patients. 14 patients had the labrum reinserted. Mean 3 suture anchors. The depth of resection for CAM was recorded (mean 4 mm’s) and extent of rim-trimming was 3 mm. 5 patients had a psoas tenotomy. All patients had antibiotic prophylaxis. No perioperative complications. All patients had significant improvements in iHOT12 and HAGOS scores at 1 year. NRS scores also improved significantly.
Conclusions: 1 year PROM data show promising early outcomes in these young patients. In the future larger patient numbers and follow-up data will hopefully improve indications and patient selection for hip arthroscopy procedures.

153. Cementless Metaphyseal Sleeves without Stem in Revision Total Knee Arthroplasty
David Gøttsche, Thomas Lind, Thorbjørn Christiansen, Henrik Morville Schrøder
Ortopædkirurgisk, Gentofte

Background: Revision knee arthroplasty with cementless metaphyseal sleeve is suggested used without stem in revision total knee arthroplasty (rTKA). In order to assess the relevant indications, this study is needed. No papers investigating this have been published.
Purpose / Aim of Study: We wanted to review the results of this concept in order to assess clinical outcome and relevant indications.
Materials and Methods: In this retrospective study we identified 71 patients operated with revision knee arthroplasty with cementless metaphyseal sleeves without stem in the period 2009-2011. All patients with the prosthesis still in place were invited to a medical examination including x-rays. We used the American Knee Society Score (AKSS) and The Oxford Knee Score (OKS) as the primary clinical outcomes.
Findings / Results: We found a significant increase in AKSS; from 62.7 to 109.6; (p-value <0.0000001) and a postoperative OKS of 32.1. We found an overall satisfaction of 2.5 on a four stage scale, going from very satisfied to dissatisfied (range 1 - 4). The Anderson Orthopaedic Research Institute (AORI) classification showed 63 % of the tibias and 56 % of the femurs to be AORI type 2B, whereas 19 % tibias and 5 % femurs were AORI type 3. The review of the x-rays showed all prostheses fixed. The mean number of revisions was 1.7 (range 1 - 5). Six patients were not evaluated. One died, one had an above knee amputation, and four were revised (one infection, one aseptic loosening; one instability, and one pain without loosening).
Conclusions: We found that the prostheses were overall well fixed and patients’ AKSS increased significantly. Many patients had comorbid pain conditions, and realistic expectations are crucial in order to get satisfied patients.

154. Pain distribution in primary care patients with hip osteoarthritis – a descriptive study
Erik Poulsen, Søren Overgaard, Jacob Toft Vestergaard, Henrik Wulff Christensen, Jan Hartvigsen
Research, Nordic Institute of Chiropractic and Clinical Biomechanics; Department of Orthopaedic Surgery and Traumatology, Odense University Hospital; Department of Sports Science and Clinical Biomechanics, University of Southern Denmark

Background: When adult patients present in primary care with hip pain, the most common diagnosis is hip osteoarthritis (OA). A number of studies have reported pain location and distribution in hip OA patients but findings relate to patients just prior to total hip arthroplasty (THA) and include patients with rheumatoid arthritis, osteonecrosis and severe dysplasia. A single study has examined pain location in primary care patients with hip pain but 2/3 of the patients did not have hip OA.
Purpose / Aim of Study: To describe pain location and pain distribution in a cohort of primary care patients with unilateral hip OA.
Materials and Methods: Primary care patients with unilateral early to moderate clinical and radiographic hip OA recorded distribution of hip pain on a manikin displaying three separate planes: frontal, back and lateral views. Pain drawings were analysed using a template and drawings were subsequently digitally processed to produce a composite image.
Findings / Results: A total of 109 patients completed pain drawings. The mean age was 65 (SD 9), 44% were females, the right/left hip ratio was 66/43 respectively, the mean pain duration was 32 months (SD 36, range 4 – 300), and mean pain intensity was 5.4 (SD 2.0). A minority of patients reported pain in only one area, most commonly the greater trochanter area (16%). No patients marked pain exclusively in the areas of the knee, posterior thigh or lower leg.
Conclusions: The most common pain locations of symptomatic hip OA presenting in primary care are the greater trochanter, groin, thigh and buttock areas. When adult patients in primary care present with pain in the greater trochanter, groin, anterior lateral thigh or buttock areas, the clinician as a minimum should include a physical examination of the hip joint.

155. The effect of periacetabular osteotomy (PAO) on the clinical outcome in patients with retroverted acetabulum - a prospective cohort study
Victoria Schmiegelow, Bjarke Løvbjerg Viberg, Ole Ovesen, Søren Overgaard
Orthopaedic Surgery and Traumatology, Odense University Hospital, Denmark

Background: A retroverted acetabulum can cause pincer impingement with deep groin pain, reduced quality of life and activity level. Retroverted acetabulum is over time to be associated with osteoarthritis (OA). Few studies have evaluated the effect of PAO and reorientation of the retroverted acetabulum and this is the first Danish cohort.
Purpose / Aim of Study: was to investigate the effect of PAO in patients with retroverted acetabulum and pincer impingement on pain, clinical outcome and quality of life.
Materials and Methods: Inclusion criterias were daily pain for at least 6 months, positive impingement test and verified retroverted acetabulum on radiographs and CT- scan. Patients had no OA. Exclusion criterias were previous operation in the hip for any reason. The patients were operated from December 2004 - May 2013 with at least 1 year of follow-up. They were scored with HHS, EQ5D-3L and VRS (pain on verbal rating scale) pre- and postoperatively. In addition, they were evaluated on 3 Anchor questions regarding their hip.
Findings / Results: 106 patients (83F) with 120 PAO with a median age of 21.4 years (IQR 18.1-26.8) were included. The median follow-up time was 1.1 year (IQR 1-1.6). The median HHS (IQR) improved from 68 (61-72) to 94 (91- 96). Median (IQR) VRS improved from 8 (6-9) to 0 (0-2). Median (IQR) EQ5D- 3L improved from 0.72 (0.66-0.77) to 0.824 (0.72-1). Compared to preoperative HHS, VRS and EQ5D-3L all improved significantly (p< 0.0001, Wilcoxon matched sign rank test). 78- 80 % reported good to excellent health and result of PAO and a better hip function than prior to surgery.
Conclusions: PAO for a patient with pincer impingement and retroverted acetabulum shows good postoperative results regarding HHS, VRS, EQ5D-3L and specific anchor questions.

156. Evaluation of bone mineral density and bone markers in femoral amputees prior to osseointegrated implant surgery
Rehne Lessmann Hansen, Peter Holmberg Jørgensen, Kjeld Søballe, Klaus Kjær Petersen, Maiken Stilling
Department of orthopaedic research, University Hospital of Aarhus; Department of orthopaedic surgery, University Hospital of Aarhus

Background: Amputees often have radiological halisteretic bone in the residual femur. The status of periimplant bone mineral density (BMD) and general skeletal bone activity may offer important information prior to osseointegration (OI) surgery.
Purpose / Aim of Study: Evaluation of preoperative data of the first 20 patients.
Materials and Methods: 20 patients (13 male) with mean age 48 (range 30-66) years, and mean 10.5 (range 0-39) years since amputation, were scheduled for surgery with an OI-implant. Preoperative assessment included AP and LA radiographs of the femur, DXA scans with measurement of systemic and femoral/pelvic bone mineral density (BMD) and thigh muscle mass, and biomarkers (BASP bone-type, Ca2+, PTH, D2+D3, creatinine).
Findings / Results: Mean length of the residual femur was 20.3cm (range 4.7–41cm). 9 patients had a normal systemic BMD (T>-1), 9 were osteopenic ((T ≤ -1), and 2 patients were osteoporotic ((T < -2.5) (male:30 yr, male:45yr). The BMD of the femur, hip and pelvis on the amputated leg was decreased by 40%, 35% and 21%, and the muscle mass in the gluteal region and femur was decreased by 9,5% and 47,5%, compared to the healthy leg (p<0.001). The BMD in the distal 12 cm of the amputated femur correlated positively with the length of the femur (spearman’s rho 0.64, p=0.002) and negatively with the years since amputation (spearman’s rho -0.71, p=0.0004). 7 patients had vitamin D insufficiency, 5 patients had elevated PTH-levels, 5 patients had elevated BASP and all had normal Ca2+ and BASP bone-type.
Conclusions: Femoral amputees have an almost 50% reduced BMD and muscle mass in the affected leg and the degree depends on the years since amputation and the length of the residual femur. Low systemic BMD and vitamin D insufficiency with sec. hyperparathyroidism was seen in 1/3 of patients indicating a general need for screening.

157. Amputation after failed knee arthroplasty
Tinne B Gottfriedsen Tinne Brandt Gottfriedsen, Anders Odgaard Anders Odgaard, Henrik M Schrøder Henrik Morville Schrøder
Department of Orthopaedics, Copenhagen University Hospital Gentofte

Background: Existing data on amputation for failed knee arthroplasty is limited. Data from the Danish Knee Arthroplasty Register (DKR) suggests that only 3 amputations have been performed since 1997.
Purpose / Aim of Study: To identify the incidence and causes of above knee amputation after failed knee arthroplasty.
Materials and Methods: Nationwide data was extracted from the Danish Hospital Episodes Statistics and DKR. Relevant patient notes were retrospectively reviewed.
Findings / Results: We identified 89,545 primary knee arthroplasties performed in Denmark from 1997-2013. 250 arthroplasties were followed by amputation corresponding to an overall crude incidence of 0.28%. Of these, 111 were performed for causes related to the knee arthroplasty corresponding to an incidence of 0.12% (range among regions, 0.07-0.16%, p=0.42). Survival data will be presented. Mean age was 69.1 years (66.9-74.5, p=0.80). Mean time between primary arthroplasty and amputation was 4.1 years (1.8-5.5, p=0.16). The patients underwent an average of 2.7 knee surgeries prior to amputation including arthrodesis in 23 cases (1.7-3.8, p=0.06). 54% of cases were assessed at a highly specialised hospital (18-90%, p=0.001). Indications for amputation included infection in 91 cases (82%), soft tissue deficiencies in 24 cases (22%), bone loss in 20 cases (18%), extensor mechanism disruption in 11 cases (10%), pain in 10 cases (9%), periprosthetic fracture in 10 cases (9%) and vascular complications in 9 cases (8%). In 88 cases (79%) there were at least two or more indications for amputation.
Conclusions: We found significantly more amputations than reported to DKR. 56% of these were performed for causes other than failed knee arthroplasty. The majority of amputations related to failed knee arthroplasty were performed for several indications, of which infection was present in most cases.

158. Acceptable agreement between Inertia-based Measurement Unit and Optical Motion Capture System applied in quantitative measurement of physical function in patients
Inger Mechlenburg, Peter Bo Jørgensen, Henrik Sørensen, Dennis B Nielsen, Bernd Grimm, Kjeld Søballe
Orthopaedic Research, Aarhus University Hospital; Section of Sports, Aarhus University; ATRIUM Medical Center, AHORSE Foundation, The Netherlands

Background: There is need for valid objective measures of physical function when outcome after orthopaedic or rehabilitation interventions are evaluated.
Purpose / Aim of Study: The aim of this study was to validate an Inertia-based Measurement Units (IMU) against an Optical Motion Capture System (OMCS).
Materials and Methods: Ten patients (eight females), mean age 28 (16-43) years with hip dysplasia were tested. The test battery included four lower extremity performance measures: sit-stand-sit (STS), stair climbing (SC), block stepping test (BST) and counter movement jump (CMJ). We applied an IMU (Micro Strain Inertia-Link) and recorded data at 100 Hz. Kinematic data were recorded at 240 Hz with an 8-camera ProReflex MCU 1000 OMCS. Rotations were measured as range between highest and lowest value. Agreement between the two systems was analyzed and presented with Limits of Agreement (LOA) (mean difference ±1.96 x SD).
Findings / Results: Overall, the agreement between the results acquired by the IMU and the OMCS was acceptable. LOA for rotations in the frontal plane in degrees for STS were 3.7±15.4 in ascending and 3.3±11.1 in descending. For SC, LOA for rotations in the sagittal plane were 2.2±6.9 deg in ascending and -3±5.8 deg in descending. LOA for rotations in the sagittal plane at the BST were -0.7±5.3 deg in ascending and -1.2±5.9 deg in descending. LOA for vertical translation for CMJ were -0.6±5.5 cm. There were systematic differences between the IMU and OMCS in SC (mean diff 2.2 deg p=0.03 and mean diff -3 deg p<0.01 respectively).
Conclusions: The IMU showed acceptable agreement with OMCS when applied in test of physical function in patients. There is a clear perspective for clinicians to apply the IMU in the evaluation of orthopaedic or rehabilitation interventions.

159. Intervertebral disc degenerative changes after intradiscal injection of TNF-α in a porcine model
Ran Kang, Haisheng Li, Kresten Rickers, Steffen Ringgaard, Lin Xie, Cody Bünger
Orthopaedic Research Lab, Aarhus University, Aarhus C 8000, Denmark; The MR Research Centre, Aarhus University Hospital, Skejby, Aarhus C 8000, Denmark; Department of Orthopedic Surgery, Jiangsu Province Hospital on Integration of Chinese and Western Medicine, Nanjing 210028, China

Background: While high expression of tumor necrosis factor-α (TNF-α) is commonly found in already degenerated discs, whether or not exogenous TNF-α will initiate a degeneration process in a healthy disc in vivo has not been studied assertively.
Purpose / Aim of Study: To investigate whether exogenous TNF-α will initiate intervertebral disc degeneration.
Materials and Methods: Exogenous TNF-α in dosages of 50 ng and 100 ng in 50 ¦ÌL Dulbecco¡¯s Modified Essential Medum (DMEM) was injected into porcine lumbar discs; a third disc was injected only with 50 ¦ÌL DMEM as a control. Magnetic resonance imaging (MRI) yielding T1- and T2-weighted images, T2 maps, and post-contrast T1 images was performed and histology was studied as well.
Findings / Results: After three months, a significant decrease in T2 value was observed in the annulus and nucleus of both groups injected with TNF-α along with a slight decrease in disc height and nucleus volumes in comparison to the control discs. No obvious differences among the groups were observed in the normal T1- and T2-weighted MRI images. Post- contrast T1 MRI showed increased annulus enhancement in both TNF-α- injected groups compared to the control discs, while no enhancement difference was observed in the nucleus. Histological analysis showed degenerative changes with annulus fissure, cell cluster, nucleus matrix loss, and vascularization in the outer annulus of both TNF-α- injected discs, while no degenerative changes were observed in the control discs.
Conclusions: Intradiscal injection of exogenous TNF- α caused disc degeneration in a porcine model. Accordingly, such preventive measures as anti- inflammatory treatment might be considered as a means of protecting the disc when there are high TNF-α levels in the serum.

160. A month of heavy resistance exercise increases the amount of Collagen XIV in the endomysium close to the human MTJ
Jens Rithamer Jakobsen, Abigail Mackey, Andreas Knudsen, Manuel Koch, Michael Kjaer, Michael Rindom Krogsgaard
Department of sportstraumatology M51, , Bispebjerg University Hospital; Institute of Sports Medicine Copenhagen, Department of Orthopaedic Surgery M, and Department of Biom, Bispebjerg University Hospital and University of Copenhagen; Institute for Dental Research and Oral Musculoskeletal Biology, and Center for Biochemistry, Medical Faculty, University of Cologne, Cologne, Germany

Background: Strain injuries are a common cause of absence from sports. They occur most often at the myotendinous junction (MTJ). So far the best prevention seems to be heavy resistance exercise (HRE), but it is unknown which adaptions HRE induces in the human MTJ that could explain this lowering in risk of strain injuries.
Purpose / Aim of Study: To investigate how the MTJ and endomysium adapts to one month of HRE training.
Materials and Methods: Ten patients scheduled for cruciate ligament reconstruction with a hamstrings graft were randomized into either a control group or a training group (1 month of HRE). At the operation, samples were collected from the semitendinosus and gracilis MTJ and fixed in liquid nitrogen-cooled isopentane. Samples were sectioned and stained with immunofluorescent antibodies against seven collagen types. The amounts of collagen were estimated visually using a scale from 0-2 where 2 is the highest amount.
Findings / Results: Compared with our control group, a significantly higher collagen XIV content of the muscle endomysium (P = 0,0132) was found in the training group. No significant differences for any of the investigated collagen types where seen at the MTJ.
Conclusions: 1 month of HRE does not lead to detectable increases in the amount of collagen I, III, IV, VI, XII and XIV at the MTJ. However, it leads to a significant increase in collagen XIV content in the endomysium of human muscle tissue close to the MTJ. These findings suggest that collagen XIV has a role in the adaptation of the connective tissue sheath to heavy loading. It is possible that longer training periods are required to induce measurable increases for the other collagen types at the MTJ or alternatively that structural changes increasing the muscle-tendon contact area explain the improved resistance to strain injury at the MTJ after HRE.

161. Pharmacokinetics of vancomycin in porcine bone obtained by microdialysis
Mats Bue, Hanne Birke-Sørensen, Theis Muncholm Thillemann, Kjeld Søballe, Mikkel Tøttrup
Department of Orthopaedic Surgery, Hospital Unit Horsens; Orthopaedic Research Unit, Aarhus University Hospital

Background: Traditionally, the pharmacokinetics of antimicrobials in bone has been investigated using bone biopsies, which suffers from considerable methodological limitations. Microdialysis (MD) offers an attractive alternative to obtain bone concentrations of antimicrobials.
Purpose / Aim of Study: The aims of this study were to investigate the suitability of the MD-method for vancomycin measurement in a laboratory setting and to apply MD for measurement of vancomycin in subcutaneous tissue, cancellous and cortical bone.
Materials and Methods: Laboratory studies were conducted to determine in vitro recovery by gain and by loss (1-25 µg/ml), appropriate flow rate, calibration concentrations and the effect of temperature and concentration on recovery. In a porcine study MD-catheters were placed in subcutaneous tissue, cancellous and cortical bone. CMA 63 catheters were used, and were in bone placed in drill holes, made by use of a 2 mm drill. Blood samples were drawn from a central venous catheter. CMA 107 pumps produced flow rates of 0.5 µl/min. All dialysates were analysed with an UHPLC-method, and vancomycin concentrations in plasma were determined with cobas (c501, Roche). Verification of catheter locations was performed by autopsy, and intra cortical placement of drill holes was verified by post-mortem CT.
Findings / Results: Laboratory study: Recovery by gain equalled recovery by loss, and was independent of the concentration. Recovery increased slightly with increasing temperature. Porcine study: For all extravascular tissue, a heterogeneous distribution was demonstrated. Significant differences in AUC were found for bone, cancellous as well as cortical, when compared to free plasma. The lowest AUC was found in cortical bone.
Conclusions: MD is a reliable method for assessment of the penetration and pharmacokinetics of vancomycin in bone and soft tissue.

162. Collagen types and distribution at the human myotendinous junction (MTJ)
Jens Rithamer Jakobsen, Abigail Mackey, Andreas Knudsen, Manuel Koch, Michael Kjaer, Michael Rindom Krogsgaard
Department of sportstraumatology M51, , Bispebjerg Hospital, University of Copenhagen, Denmark.; Institute of Sports Medicine Copenhagen, Department of Orthopaedic Surgery M, and Department of Biom, Bispebjerg University Hospital and University of Copenhagen; Institute for Dental Research and Oral Musculoskeletal Biology, and Center for Biochemistry, Medical Faculty, University of Cologne, Cologne, Germany

Background: The MTJ is the interface between the muscle and tendon, through which force produced in the muscle is transmitted. Excessive loading of muscles can result in strain injuries, which often occur at the MTJ. However, very little is known about the composition of the human MTJ. In animals, collagen type XXII seems to be located exclusively in the MTJ, and has been shown to contribute to the stabilization of MTJ and strengthening of skeletal muscle attachments during contraction. Similarly, a lack of Collagen XXII results in a higher susceptibility to ruptures of the MTJ.
Purpose / Aim of Study: The aim of this study is to investigate the distribution of collagen type XXII in human MTJ and the localisation of other collagen types (I, III, VI, XII, XIV) in relation to collagen XXII.
Materials and Methods: Samples of MTJ were collected from the hamstring muscles of 15 patients during ACL-reconstruction and frozen in liquid nitrogen, cut on a cryostat and stained with antibodies against collagen I, III, IV, VI, XII, XIV and XXII. The sections were analysed immunohistochemically with fluorescent wide-field and confocal microscopes and the amounts of stained protein were estimated visually on a score from 0 to 2, where 2 is highest.
Findings / Results: Collagen XXII was located only at the MTJ, but not in all regions. It was detected between the dystrophin-labelled myofibre membrane and the endomysium, which was rich in collagen types III and VI. Collagen types XII and XIV were also observed to be closely associated with XXII.
Conclusions: The human MTJ has a very complex composition of different collagen types. The possible roles of these collagens in force transmission are discussed. Collagen type XXII was the only type to be solely located at the MTJ, and is therefore a valuable marker for human MTJ even though it is not found in all regions.

Carsten Jensen, Signe Rosenlund, Dennis B. Nielsen, Søren Overgaard, Anders Holsgaard-Larsen
Orthopaedic Research Unit, Department of Orthopaedic Surgery and Traumatology, Odense University Hos, Institute of Clinical Research, University of Southern Denmark; Departments of Orthopedic Surgery and Traumatology, Køge and Odense Hospital; Orthopaedic Research Unit, Department of Orthopaedic Surgery and Traumatology, Odense University Hospital

Background: Three-dimensional gait analysis (3DGA) is widely used in the quantitative evaluation of gait. However, 3DGA produces a large volume of data, and simplifying such complex data into a single measure of patients overall gait ‘quality’ would be valuable in clinical practice. The experience with GDI in osteoarthritis (OA) patients following total hip arthroplasty (THA) is novel.
Purpose / Aim of Study: The aim of our study was to use the GDI to evaluate post-operative gait quality changes in patients with hip OA following two types of THA.
Materials and Methods: A total of 38 patients (11F:27M, age 56 ± 5.6, BMI 27.8 ± 3.6) with unilateral end-stage primary hip OA were evaluated pre-operatively, two- and six- months after THA, while walking at self- selected speed. From the entire gait cycle, rather than a small number of discrete parameters, the GDI was calculated for each limb (n=76 limbs). The normative mean and standard deviation from age-matched controls (n=20) were used as reference. A fixed-effects multilevel regression model was employed to evaluate the treatment effects.
Findings / Results: Patients had a moderate deviation from normative gait (score = 100) before surgical treatment (83.4 ± 10.9). After surgery, the score improved significantly by 4.9 [95CI: 2.1 to 7.9]. There was no difference in GDI scores between the two treatments; 1.8 [95CI: -2.8 to 6.4]. However, the GDI score for the non-operated limb was higher than the GDI score for the operated limb; 2.5 [95CI: 0.1 to 4.8].
Conclusions: GDI increased after THA, which indicates an overall improvement in gait quality. No difference between treatments was observed. Asymmetrical gait pattern do not disappear following THA. Further research is required to establish the clinical relevant difference for the GDI score for THA patients.

164. Validation and inter-tester reliability of a tri-axial accelerometer-based classification of daily activities
Marianne Tjur, Kenneth Juul Laugesen, Kamilla Nygaard Jensen, Mads Grosmann Svendsen, Inger Mechlenburg, Signe Kierkegaard
Orthopaedic Research, Aarhus University hospital; Bachelor of Applied Science in Physiotherapy, VIA University College Aarhus

Background: Daily physical activities (PA) are often used as outcome in the evaluation of orthopaedic or rehabilitation interventions. Self-reported PA suffers from recall bias and imprecision, thus there is a need for objective measures.
Purpose / Aim of Study: The aim was to investigate the inter-tester reliability and precision of the classification of PA measured with a tri-axial accelerometer, and a MatLab-based algorithm.
Materials and Methods: 27 healthy participants were observed with video recordings while performing 30 min of various time intervals of the activities; resting, standing, walking, cycling and running. A tri-axial accelerometer (GCDataconcepts, US) was mounted on lateral side of right thigh while performing the activities. Two blinded analysers performed the classification of activities using the algorithm. The relative reliability was expressed with Intraclass Correlation Coefficient (2,1)(ICC), the absolute reliability with Limits of Agreement (LOA) and precision with LOA of the proportion of analysed activity compared to observed.
Findings / Results: ICC was high for resting 0.99, standing 0.99, walking 0.88 and running 0.99 and acceptable for biking 0.73. LOA were acceptable for resting [-0.34;0.42], standing [-0.98;1.28], walking [-449;368], running [-0.39;0.32] and biking [-368;448]. The precision of classifying PA was acceptable with LOA [0.99:1.02] for resting, [0.94:1.10] for standing and [0.98:1.07] for biking. Walking was underestimated (mean= 0.71 (p=0.03), LOA [0.19:2.60]) while running was overestimated (mean= 1.39 (p=0.001), LOA [0.64:2.98]).
Conclusions: Inter-tester reliability was high while precision of classification of resting, standing and cycling was acceptable. More precision is necessary in the classification of walking and running. The perspectives for monitoring daily PA with accelerometer seem promising.

165. Does an intensive alcohol cessation intervention at the time of fracture surgery induce spontaneous smoking cessation? - The Scand-Ankle study
Erika Wernheden, Marianne Aalykke, Bolette Pedersen, Julie W. M. Egholm, Hanne Tønnesen
WHO-CC, Frederiksberg Hospital; Clinical Health Promotion Centre, Lund University; Syddansk Universitet, Sygehus Sønderjylland

Background: Patients with high alcohol consumption are at greater risk of developing postoperative complications than patients with low/no alcohol consumption. Other risk factors are smoking, overweight, malnutrition and physical inactivity. Preoperative alcohol and smoking cessation programs have been found effective in reducing postoperative morbidity, but it remains unknown whether these induce a general change of lifestyle.
Purpose / Aim of Study: The aim of this study was to find out whether the gold standard alcohol intervention programme (GSP-A) used in the Scand-Ankle study, affected smoking, overweight, malnutrition and physical inactivity.
Materials and Methods: 64 patients with high alcohol consumption, who underwent ankle fracture surgery, were randomized to the GSP-A or usual care (control). The two groups were compared at baseline and 6 weeks follow- up regarding changes in lifestyle factors. Data were analyzed on an intention to treat (ITT) basis using non-parametric statistics. A per protocol analysis of whether alcohol cessation, regardless of study group, affected lifestyle risk factors after 6 weeks was also performed.
Findings / Results: The ITT-analysis showed no significant differences between the GSP-A and control group regarding lifestyle risk factors other than alcohol. The per protocol analysis showed that alcohol cessation regardless of study group did not influence the other lifestyle risk factors.
Conclusions: The GSP-A, which has been proven effective on short-term alcohol cessation, does not affect smoking, overweight, malnutrition and physical inactivity. Thus, a potential effect of the GSP-A on postoperative complications will likely be due to the effect on alcohol intake and not to a general change in lifestyle. The findings suggest that multiple lifestyle interventions are required, e.g. combined alcohol and smoking cessation.

166. Compression in Anklefracture Treatment, the CAT-study
Rikke Winge, Stig Sonne-Holm, Camilla Ryge , Hans Gottlieb, Lasse Bayer
Orthopedic Surgery, Nordsjællands Hospital

Background: Malleolar fractures in Denmark has an incidence of 107/100.000 person, making it one of the most common fracture types in the country. In Denmark 6000 malleolar fractures are operated each year. Studies have shown increased complication rates in the elderly, diabetics, smokers, patients on immunomodulating medication, alcoholics, and patients with osteoporosis and peripheral neuropathy. Nordsjællands Hospital has decided, to implement a standard regime of elevation, Flowtron Hydroven 3™ and Coban™ 2 lite, to prevent oedema formation and blistering. The decision came after clinicians having observed a high incidence of oedema, blistering and wound healing problems in this cohort of patients, often forcing surgeons to postpone surgery and prolonging inpatient stay, resulting in a long and cumbersome rehabilitation for the patient.
Purpose / Aim of Study: To perform a randomized, controlled cohort study, to evaluate the effect of Flowtron Hydroven3™ and Coban2 lite™ on the incidence of complications (infection, wound dehiscence, prolonged healing, skin necrosis, exposed hardware, DVT, amputation and death) after operation for mono-, bi- and trimalleolar fractures at Nordsjællands Hospital.
Materials and Methods: 156 Patients with an unstable malleolar fracture, included and randomized in the ED. Intervention: Compression therapy in the form of Flowtron Hydroven3™ and Coban2 lite™compression bandage. Controle: Elevation of the ankle on a Braun frame. Follow-up: 6 weeks. The project manager will note any wound healing problems (infection, wound dehiscence, skin necrosis, visible osteosynthesis material).
Findings / Results: By the time of the DOS-congress, the authors are ready to present the preliminary data, concerning the first 78 patients (50% of expected)
Conclusions: Awaiting analysis of preliminary data.

167. Characteristics of non-participants in orthopaedic research – A study of patients undergoing ankle fracture surgery and declining participation in a randomized clinical trial
Marianne Aalykke, Erika Wernheden, Bolette Pedersen , Julie Weber Melchior Egholm, Hanne Tønnesen
WHOCC, Clinical Health Promotion Centre, Frederiksberg Hospital; WHOCC, Clinical Health Promotion Centre and Clinical Alcohol Research, Frederiksberg Hospital and Lund University ; WHOCC, Clinical Health Promotion Centre and Orthopedic Surgery, Frederiksberg Hospital and Sygehus Søndejylland ; WHOCC, Clinical Health Promtion Centre and Clinical Alcohol Research, Frederiksberg Hospital and Lund University

Background: Clinical experience indicates that patients declining participation in randomized clinical trials (RCTs) are older, less healthy and of lower social status than participants, bringing the non-participants in a higher risk at surgery. Results from studies investigating non-participants of RCTs in surgical settings are conflicting, and to our knowledge none of these studies exist on patients with risky drinking, who are already at high risk at surgery.
Purpose / Aim of Study: The aim of this study was to investigate characteristics and outcomes of patients undergoing ankle fracture surgery with risky drinking declining participation in the Scand-Ankle RCT.
Materials and Methods: The Scand-Ankle study is an on-going RCT, that investigates the effect of a 6- week gold standard alcohol intervention (GSP-A) on postoperative complications in patients drinking >21 units/week and undergoing ankle fracture surgery. This retrospective study included eligible patients that declined to participate in the Scand-Ankle RCT, but gave informed consent to follow-up in their medical record (N=67). Their perioperative patient characteristics and 6-week complication rate were obtained from their medical record material and the characteristics were compared to the patients enrolled in the study so far (N=61).
Findings / Results: The analyses on patient characteristics are on-going. 34% of the non-participants had complications, and the most frequent complication was wound infections.
Conclusions: A complication rate at 34% indicates that patients drinking > 21 units/week are at high risk at ankle fracture surgery, and the analyses on patient characteristics will show if the non-participants are at even greater risk.

168. Early Complications of Ankle Fractures Following Treatment with Ilizarov External Fixator or Open Reduction Internal Fixation
Josefin Roslund , Matilda Svenning, Michael Brix, Morten Schultz Larsen
Orthopaedic Surgery, Odense University Hospital

Background: Objective: Open reduction and internal fixation (ORIF) is the standard surgical treatment for ankle fractures in Denmark. In cases of compromised soft tissue, the Ilizarov external fixator (IEF), might be a safer alternative when fixation is needed.
Purpose / Aim of Study: The aim of this study is to analyse the short term complications following treatment of ankle fractures using IEF or ORIF.
Materials and Methods: Method: The study population consisted of 122 consecutive patients who were surgically treated for ankle fractures at Odense University Hospital (OUH) during the time period 01.05.2012 – 31.04.2013. Patients were divided into groups based on surgical treatment method (IEF or ORIF). Pre- defined outcomes, predisposing factors and other variables of interest were registered from medical records and x-rays.
Findings / Results: Results: 23 patients received IEF treatment and 99 received ORIF. Among the predisposing factors the variable “hypertension and/or hyperlipidemia” varied significantly, occurring more often in the IEF group, whereas the rest of the predisposing factors did not. Among the defined postoperative outcomes secondary loss of reduction showed a significant higher rate in the IEF group. Infection and reoperation did not differ significantly between the groups. No case of compartment syndrome or amputation occurred in any of the groups.
Conclusions: Conclusion: Even though the patients in the IEF group were generally considered to be in poorer condition prior to operation (higher age and rate of predisposing factors), the only outcome that was significantly different was secondary loss of reduction. This is consistent with the theory that IEF might be a good alternative for patients with less desirable preoperative conditions.

169. The epidemiology of acute Achilles tendon ruptures in the south Copenhagen area in the period 2004 - 2013
Ann Ganestam, Anders Troelsen, Kristoffer W. Bartfod
Orthopedic surgery, Copenhagen University Hospital Hvidovre

Background: Acute Achilles tendon rupture (ATR) is a frequent and potentially disabling injury that typically occurs among young active adults. Epidemiological studies have shown an increasing incidence but data are old and might not be accurate. The last epidemiological study from Denmark was published in the year 1998 and showed an increase from 18.2/10⁵ inhabitants in 1984 to 37.3/10⁵ in 1996.
Purpose / Aim of Study: To investigate the incidence of acute Achilles tendon rupture in the south Copenhagen area from 2004 to 2013 with focus on sex, seasonal variation and changes over time.
Materials and Methods: By using the ICD-10 code for acute Achilles tendon rupture (DS86.0) the National patient register was searched to find the number of acute Achilles tendon ruptures at Hvidovre Hospital in the time period of 2004-2013. Information concerning sex, date of treatment and month of injury was retrieved. Regional population data for the region of south Copenhagen was retrieved from the Hospital administration.
Findings / Results: An increase in incidence from 15.8/10⁵ in 2004 to 23.0/10⁵ in 2013 was found. 22% were women and 78% were men. The seasonal incidence over the ten year period showed a distribution with peak incidence in May (20.6/10⁵) and September (18.1/10⁵). The lowest incidence was found in July and December (8.6/10⁵).
Conclusions: The incidence of ATR increased from 15.8/10⁵ to 23.0/10⁵ over the ten year period. However, the incidence is markedly lower than the incidence of 37.3/10⁵ found in 1996. As such there is no evidence of a continuing rise in incidence of ATR. The seasonal variation is supported by earlier epidemiological studies. It might be explained by the seasonal variation in activity in recreational sports and gymnastics.

170. Regional Differences in Number of Meniscal Procedures in Denmark
Kristoffer Borbjerg Hare, Jesper Høeg Vinther, L Stefan Lohmander, Jonas Bloch Thorlund
Department of Sports Science and Clinical Biomechanics, University of Southern Denmark; Department of Orthopedic, Kolding Hospital

Background: A recent study reported a large increase in the number of arthroscopic meniscal procedures from 2000-2011 in Denmark. This large increase was observed almost exclusively in middle- aged and older patients. Regional differences have previously been reported for the use of surgical interventions.
Purpose / Aim of Study: In this study we examined regional differences in number of meniscal procedures performed in Denmark.
Materials and Methods: We extracted data from the National Patient Register. Data was retrieved on all patients who underwent arthroscopic meniscus surgery either as primary procedure or part of other surgery in the years 2005 to 2011. Data was extracted on age, sex and hospital identification code for each contact, which enables linkage of performed procedures to hospital and regional location. Yearly incidence rates per 100 000 were calculated (with 95 % confidence intervals) for all procedures performed in each of the five regions in Denmark.
Findings / Results: From 2005 to 2011 the overall yearly incidence rate increased from 214 (210-217, 95% CI) to 312 (307-316, 95% CI). In the Capital Region the incidence rate more than doubled from 165 (159-171, 95% CI) to 366 (357- 375, 95% CI). In Region Mid the incidence rate increased from 255 (246-264, 95% CI) to 294 (284-303, 95% CI) while the highest incidence rate was observed in the Region of Southern Denmark rising from 298 (288-308, 95% CI) to 438 (426-450, 95% CI). In Region Zealand and Region North there was a slight decrease from 131 (123-139, 95% CI) to 124 (116-131, 95% CI) and 206 (195-218, 95% CI) to 195 (183-206, 95% CI), respectively.
Conclusions: Large regional differences were apparent in the use and increase of meniscal procedures in Denmark from 2005-2011. In 2011 the incidence rate in Region of Southern Denmark was 3.5 times greater than in Region Zealand.

171. Differences in MACI® Patient Characteristics in European Countries
Casper Bindzus Foldager, Martin Lind
Orthopaedic Research Lab, Aarhus University Hospital; Sports Trauma Clinic, Aarhus University Hospital

Background: Matrix-Assisted Chondrocyte Implantation (MACI®) is a commercially available cell- based technique for treatment of articular cartilage defects. Randomized controlled trials has suggests the use of this treatment for younger patients with focal cartilage lesions in the knee larger than 3cm2.
Purpose / Aim of Study: To investigate demographics and cartilage defect sizes of patients receiving MACI® treatment in the knee in European countries.
Materials and Methods: Data was obtained from the Sanofi™ database on patients receiving autologous chondrocyte cultured in the European Sanofi™ facility in Copenhagen, Denmark. Countries with more than ten patients treated from 2008-2013 were included. Patient demographics (age, gender) and cartilage defect characteristics (size, number of defects) were evaluated. Data was analyzed using one-way ANOVA analyses. P-values < 0.05 were considered significant.
Findings / Results: A total of 1909 patients from 9 European countries, including Denmark, were eligible for evaluation. The average age was 35.5 years (range 11-65) and male:female ratio of 67:33. Mean defect size was 5.70 cm2 (range 0.16-47cm2). Single defects accounted for 78% while 22% were multifocal. There were significant differences in mean cartilage defect size between the countries (p<0.0001),. On average 18.9% were small cartilage defects (<3cm2) of which 63.1% were <2cm2. Eleven percent of the cartilage defects were large (>10cm2), and thus the majority of the defects were 3-10cm2 (70%).
Conclusions: This study show differences in sizes of the cartilage defects in patients receiving MACI® treatment in 9 European countries. In general the treatments are being assigned to patients matching criteria in age and defect size for which evidence have suggested benefit of chondrocyte transplantation compared with alternative treatments.

172. PROM in the referral of patients to knee arthroscopy
Peter Christian Siesing, Claus Hjorth Jensen, Thomas Lind, Anders Odgaard
Orthopedic Surgery, Gentofte Hospital, University of Copenhagen

Background: Knee arthroscopy for knee pain, effusion and locking is commonly performed. Quality assurance of the operations was introduced in our department by the administration of the Oxford Knee Score (OKS). The measures ability to predict outcome was studied.
Purpose / Aim of Study: Can OKS help to determine which patients are candidates for a knee arthroscopy?
Materials and Methods: The OKS assessed 232 patients scheduled for knee arthroscopy preoperatively and at three months. The preoperative score was related to improvement by ≥8 points or deterioration at 3 months.
Findings / Results: Of 62 patients having a preoperative score of ≥35, 11 patients increased their score with ≥8. Of 170 patients having a preoperative score of <35, 99 increased their score by ≥8. p<0.001 chi-sq. 16 of the 62 patients with a preoperative score of ≥35 decreased their score as compared to 20 of the 170 patients with a score of <35. p<0.01 chi-sq.
Conclusions: A preoperative OKS of ≥35 suggests a fairly well functioning knee and leaves a narrow interval for improvement. Worsened knee function at 3 months was seen in one fourth of the patients with a high preoperative OKS.

173. Diagnosis and treatment of chronic exertional compartment syndrome - a proposition for an algorithm based on case series of patients treated at Sports Medicine Division, Department of Orthopaedic Surgery, Viborg Regional Hospital, Denmark
Peter Birk, Steffen Skov Jensen, Bente Overgaard Hansen, Janni Stroem
Ortopæd kirurgisk afd. T, Viborg Regionshospital; Ortopæd kirurgisk afd. T, fysioterapien, Viborg Regionshospital; Ortopæd kirurgisk afd. T, klinisk sygepleje, Viborg Regionshospital

Background: Chronic exertional compartment syndrome (CECS) is a well recognized but often under diagnosed cause of chronic exertional lower extremity pain, most often encountered in young physically active individuals.
Purpose / Aim of Study: The aim of this preliminary study is to present an algorithm for diagnosis and treatment of CECS. We hypothesize that specific activity induced strain (SAIS) can be used to diagnose the specific affected compartments, and in this way be able to safely and effectively treat this disorder using endoscopic assisted selective fasciotomy (EASF).
Materials and Methods: Retrospective follow-up study of 13 consecutive selected patients seen in the period from Nov 2011 to May 2014 (6 women and 7 men, mean age 26 years, range 15-46 years). We used an algorithm of MRI scan or bone scintegraphy to rule out other pathology. Subsequently the patient was examined by a physiotherapist and exposed to SAIS. The objective findings in conjunction with a thorough medical history formed the basis for the diagnosis.
Findings / Results: 11 patients were offered surgical treatment consisting of EASF of the affected compartment (10 bilateral and 1 unilateral, 8 affected in specific compartments and 3 affected in all compartments. Only 1 patient required additional EASF of other compartments than primarily diagnosed. At three months follow up 82% of the patients had regained their physical capabilities as prior to the condition.
Conclusions: Diagnosing CECS using an algorihm consisting of physiotherapist examination including SAIS allows the surgeon to diagnose the specific affected compartments. In our study we can conclude that this practice represents a reliable diagnostic identifier, and that EASF is a safe and effective surgical treatment. Further studies are needed to confirm the benefits.

174. Knee Joint Loading Indices Before and 3 Months after Arthroscopic Partial Medial Meniscectomy
Jonas B. Thorlund, Mark W. Creaby, Martin Englund, Nis Nissen, L. Stefan Lohmander, Anders Holsgaard-Larsen
Department of Sports Science and Clinical Biomechanics, University of Southern Denmark; , Australian Catholic University, Brisbane, Australia; Department of Orthopedics, Lillebaelt Hospital, Kolding; Department of Clinical Science and Department of Orthopedics and Traumatology, University of Southern Denmark and Odense University Hospital

Background: Increased knee adduction moment (KAM) is considered an important biomechanical marker of medial compartment loading in knee osteoarthritis (OA) research. Patients undergoing arthroscopic partial medial meniscectomy (APMM) are at increased risk of developing medial compartment knee OA. APMM may contribute to altered knee joint loading patterns. However, this is currently unknown.
Purpose / Aim of Study: The aim of this study was to determine the short-term changes in knee joint loading indices from before to after medial APMM.
Materials and Methods: We investigated indices of knee joint loading (peak KAM and KAM impulse) using 3D gait analysis in 23 middle-aged patients (17 men, 46.3 yrs (SD 6.4), BMI 25.8 kg/m2 (3.4) before and 3 months after APMM for a degenerative tear. Patients had no radiographic knee OA (i.e. Kellgren & Lawrence grade 0 or 1) in the leg undergoing APMM or in their uninjured control leg prior to surgery. Data were collected during barefoot gait at self-selected walking speed (± 5% at follow-up). Paired t-tests were used to test for differences at baseline and differences in change over time between operated and control legs.
Findings / Results: No differences were observed between the operated and uninjured control leg in peak KAM (p=0.42) or KAM impulse (p=0.14) before APMM. No difference in change from before to 3 months after APMM were observed between operated and uninjured control legs in peak KAM (0.17 [95% CI, -0.13-0.49] Nm/BW*HT%), whereas a border line significant increase was observed in the APMM leg in KAM impulse (0.09 [95% CI, -0.01-0.19] Nms/BW*HT%).
Conclusions: Knee joint loading indices - as indicated by the KAM - do not appear to substantially increase in the operated leg compared with the uninjured control leg from before to 3 months after APMM in middle-aged patients with degenerative meniscal tears.

175. Inter-tester reliability of four tests measuring muscle strength in the shoulder using a handheld dynamometer
Mikkel Bek Clausen, Peter Andreas Rothe, Jens Langermann, Per Hölmich, Kristian Thorborg
School of Physiotherapy, Institute of Rehabilitation and Nutrition, Faculty of Health and Technology, Metropolitan University; Arthroscopic Centre Amager, SORC-C, Copenhagen University Hospital, Amager-Hvidovre, Denmark

Background: Weakness in isometric shoulder protraction (PT), horizontal extension (HE), abduction (ABD) and external rotation (ER) muscle strength is reported in patients with shoulder pathology, why objective testing is relevant in both research and clinical settings. The inter-tester reliability for tests of ABD and ER using a handheld dynamometer is found to be acceptable to excellent, though most of the described tests are performed with the shoulder in positions not suitable for patients with severe problems. For test of PT and HE the inter-tester reliability has not previously been investigated and no suitable testing protocols for these tests is found in the literature.
Purpose / Aim of Study: The aim of this study was investigate the inter-tester reliability for the standardized tests of strength in shoulder PT, HE, ABD and ER, performed in positions most suitable for patients with severe shoulder problems.
Materials and Methods: Twenty-five asymptomatic adults underwent standardized testing of isometric muscle strength in PT, HE, ABD and ER measured by handheld dynamometer, using the best of two trails as the test result. Order of tests and order of tester were randomized for all participants. Relative reliability were assessed for all tests using ICC2,1 two-way mixed model - absolute agreement, thereby taking any bias between testers into account.
Findings / Results: The inter-tester reliability were excellent for tests of PT (ICC 0.92 95%CI:0.80-0.97), ABD (ICC 0.93 95%CI:0.84-0.97) and ER (ICC 0.91 95%CI:0.81-0.96), but only acceptable for test of HE (ICC 0.79 95%CI:0.45-0.91).
Conclusions: The tests of strength in shoulder PT, ABD and ER were found sufficiently reliable to be implemented in both scientific and clinical settings, while the test of strength in shoulder HE should mainly be used in scientific settings with large samples.

176. Osseointegrated (OI) Prothesis for Upper Limb Amputees.
Klaus Kjær Petersen, Peter Holmberg Jørgensen
Department of Orthopedic Surgery, Aarhus University Hospital, Aarhus, Denmark

Background: Conventional socket prothesis in upper limb amputees do not always fullfill demands for stability, comfort and function. OI prothesis is an option for upper limb amputees without or with insufficient function of a socket prosthesis.
Purpose / Aim of Study: We present the concept and our early experiences.
Materials and Methods: Since 2013 four patients have been treated with a two stages operations, where a titanium fixture is surgically inserted into the bone of the amputated limb, and (up to 3 monts later) a skin penetrating abutment to which the prosthesis is attached is inserted.
Findings / Results: 1.Woman, 56 years old, who had a MP- joint amputation of the dominant thumb. OI-procedures were completed 18 months ago and the patient is now wearing a finger prothesis. The patient has a stable and firm pinchgrib. She can hold a cake stand, knit, do embroidery cross stitchs and has some sensory feedback (osseoperception). 2. Male truck driver, 41 years old with a 10 cm short proximal humerus stump following a traumatic amputation. Conventional socket prosthesis was not possible. The patient is now using a mechanical prosthesis without elbow joint and is able to shift gears, control joystick on the truck crane and write. 3. Male carpenter, 49 years old with partial amputation on proximale phanlanges of 1., 2. and 3. finger on the dominant hand following frost bites. The second operation has recently been performed and the patient is awaiting three finger prosthesis. 4. Man, 63 years old, with a very short ulna following a traumatic forearm amputation. The second operation has recently been performed and the patient is awaiting a stable myoelectric forearm prosthesis and a free elbow joint.
Conclusions: OI prothesis is an option for selected upper limb amputees and which can improve functionality and introduce new prosthetic technology.

177. Outcome and risk of revision after shoulder replacement in patients with osteoarthritis: 1,209 cases from the Danish Shoulder Arthroplasty Registry
Rasmussen Jeppe, Anne Polk, Anne Kathrine Belling Sørensen, Bo Sanderhoff Olsen, Stig Brorson
Orthopaedic Surgery, Herlev Hospital

Background: Hemiarthroplasty (HA) including resurfacing hemiarthroplasty (RHA) and stemmed hemiarthroplasty (SHA)are widely used in Denmark but the efficacy in comparison to that of total shoulder replacement (TSA) is poorly documented.
Purpose / Aim of Study: In this study we used patient reported outcome and risk of revision to compare HA and TSA in patients diagnosed with osteoarthritis and secondly to compare SHA and RHA.
Materials and Methods: We included all patients reported to the Danish Shoulder arthroplasty registry (DSR) between January 2006 and December 2010. 1209 arthroplasties in 1109 patients were eligible. Western Ontario Osteoarthritis of the Shoulder index (WOOS) was used to evaluate patient reported outcome 1 year postoperatively. For simplicity of presentation, the raw scores were converted to a percentage of a maximum score. Revision rates were calculated by checking reported revisions to DSR until December 2011. WOOS and risk of revision were adjusted for age, gender, previous surgery and type of osteoarthritis.
Findings / Results: There were 113 TSA and 1096 HA (837 RHA and 259 SHA). Patients treated with TSA had a statistically better WOOS, exceeding the predefined minimal clinically important difference, at one year (mean difference 10, P<0.001). RHA had a statistically significant better WOOS compared to SHA (mean difference 5, P=0.024) but the difference did not exceed the minimal clinically important difference. There were no statistically significant differences in revision rate or adjusted risk of revision between any groups.
Conclusions: Our results are in accordance with the results from other national shoulder registries and the results published in systematic reviews favoring TSA in the treatment of osteoarthritis.

Britt Mejer, Niels Søe, Nina Vendel Jensen, Katalin Kiss, Lone Larsen, Lars B. Dahlin
Ortopædkirurgisk O, Hillerød Hospital; Håndkirurgisk klinik, Gentofte Hospital; Anæstesiologisk afdeling, Gentofte Hospital; Patologisk afdeling, Rigshospitalet; Radiologisk afdeling, Herlev Hospital; Håndkirurgisk afdeling, Malmø og Lund sykehus

Background: MRI imaging is considered the gold standard in order to diagnose avascular necrosis after a scaphoid fracture prior to surgery
Purpose / Aim of Study: A comparative study on ten patients who suffered from scaphoid fracture with avascular proximal pole necrosis was done, where MRI images with contrast were compared against histological findings of the excised proximal pole of the scaphoid bone. We reviewed the accuracy of MRI findings compared to histological findings of the entire proximal pole of the scaphoid.
Materials and Methods: A comparative study on ten patients who suffered from scaphoid fracture with avascular proximal pole necrosis was done, where MRI images with contrast were compared against histological findings of the excised proximal pole of the scaphoid bone. The patients were initially treated with screw fixation due to a fracture, but due to avascular necrosis of the proximal pole they were reoperated with APSI prosthesis. Prior to surgery all patients were examined with X-ray and MRI that both showed the signs of necrosis of the proximal pole of the scaphoid.
Findings / Results: All ten patients showed different degrees of avascular proximal pole necrosis in ordinary X-ray, and the histological findings showed more extensive necrosis in the bone than the MRI. The histological findings are more precise in the degree of vascularity than the MRI.
Conclusions: MRI findings seem to be less specific than the histological findings described with degree of avascular necrosis. The MRI technique with contrast that is used now will probably better correlate to histological findings.

179. Early experience with bone scan SPECT CT in assessing adolescents with complex problems in the foot and ankle region
Ole Rahbek, Deborah M Eastwood, Marina Easty, Lorenzo Biassoni
Department of Orthopaedics, Great Ormond Street Hospital for Children NHS Foundation Trust, London (UK); Department of Radiology, Great Ormond Street Hospital for Children NHS Foundation Trust, London (UK)

Background: Adolescents, particularly those with proven foot pathology, may develop unexpected foot pain during periods of changing growth rates. It can be difficult to differentiate between functional and organic foot pain.
Purpose / Aim of Study: The aim of this retrospective study was to review our preliminary experience on bone scan with SPECT CT in the assessment and management of the child with complex foot/ankle pain.
Materials and Methods: We reviewed the notes and imaging of 11 patients with complex foot and ankle pain, referred for bone scanning (12 scans performed). All patients had plain films, 7/11 patients had MRI (1 patient had CT). Bone scanning was performed with a dual head Siemens Symbia T2 SPECT/CT gamma camera. Planar blood pool and delayed static images of the feet, with SPECT/CT images of both feet and ankles, were acquired
Findings / Results: Mean age was 13yr (range 9-17), 9/11 patients were female. The underlying diagnoses were: tarsal coalition [n=3], non-specific inflammation [n=2], spastic diplegia [n=2], clubfeet [n=2], chronic regional pain syndrome, dystonic foot posturing [n=1]. Four feet had undergone previous surgical treatment. Bone scan SPECT/CT added decisive clinical value versus x-rays and MRI/CT in 9/12 cases. In four cases it prompted surgical management (fusion, screw removal, coalition excision, arthrodesis). In two patients it showed other focal areas of mechanical stress, thus excluding surgery. In 3/12 patients the bone scan confirmed the diagnosis without adding significant clinical information.
Conclusions: These preliminary results are encouraging and suggest that a prospective evaluation of bone scan with SPECT/CT in adolescents with foot pain and complex problems of the foot and ankle is justified.

180. Supramelleolar tibial osteotomy without fibular osteotomy, allowing immediate weightbearing, is safe.
Ida Marie Rahbek, Gert Rahbek Andersen
Ortopaedic dept. U, Rigshospitalet

Background: Children with cerebral palsy have a risk of developing external tibial torsion secondary to a persisting fetal femoral anteversion. External tibial torsion can lead to gait disturbances, patello- femoral instability and pain. This can be corrected by surgery, which can be performed with different procedures. These vary in terms of level of the osteotomy, the treatment regimen, the method of fixation, and whether concomitant fibular osteotomy is performed.
Purpose / Aim of Study: The purpose of this study is primarily to examine the results of supramalleolar tibial osteotomy with plate fixation and immediate weight bearing, including rate of complications and course of mobilization. Secondarily to compare this study to previous studies in terms of fixation methods and treatment regimens.
Materials and Methods: Data is collected retrospectively from medical charts at the Children’s Orthopedic Department of Rigshospitalet. The included patients were diagnosed with cerebral palsy, and received surgery in the period 1999-2013. The osteotomies were fixated with a plate, and full weightbearing was allowed. Forty patients were included, with a total of 65 osteotomies.
Findings / Results: In the 65 osteotomies, 5 complications was reported (7.7%), including 3 major complications and 2 minor. There were no cases of malunion or non-union. Median age at surgery was 14.8 years. Surgery to remove the plate was performed in 22 of the 65 osteotomies and median follow-up was 2.6 years.
Conclusions: This study shows that supramalleolar tibial osteotomy with primary weight bearing is a safe method, that doesn’t result in more frequent or severe complications, than observed with 4 weeks of immobilization without weight bearing. Primary mobilization leads to less loss of muscle mass, which is essential to the target group.

181. Biomechanical symmetry of a hip joint altered by Perthes’ disease
Remel Salmingo, Tina Skytte, Marie Sand Traberg, Kaj-Åge Henneberg , Klaus Hindsø, Christian Wong
Biomedical Engineering, Department of Electrical Engineering, Technical University of Denmark; Department of Orthopaedics, Hvidovre Hosptial

Background: Perthes is a disease characterized by a loss of blood supply of the hip joint resulting to malformation of the femoral head. Until now, the underlying biomechanical changes of Perthes’ disease need to be further elucidated.
Purpose / Aim of Study: The objective of this study was to investigate the changes specifically the biomechanical symmetry of a unilateral Perthes’ hip.
Materials and Methods: Finite Element (FE) modeling was performed to investigate the biomechanics of a healthy and diseased hip of a unilateral Perthes’ case. The image MRI slices were obtained to segment the bones and cartilages, and to build the 3D models. The elastic modulus for the pelvis, femur, cartilages and necrotic bone (Perthes’ hip only) were, 5 GPa, 500 MPa, 50 MPa, 20 MPa, respectively. The most distal part of the femur was fixed while the pelvis was displaced to -1.5 mm to simulate load.
Findings / Results: The result indicates that the symmetry of the hip joint of the unilateral Perthes’ case was altered biomechanically. The highest displacement of the healthy hip occurred at the supero-medial side of the femoral head. On the other hand, in Perthes’ hip, the displacement occurred at the superior part of the femoral head and gradually reduced towards the distal part of the femur. Localized contact pressure and stresses were also found in the Perthes’ hip.
Conclusions: As a mechanical analogy, the healthy hip is experiencing bending load similar to a curved-cantilever beam where the maximum displacement is located at the end. The Perthes’ hip resembles a stacked column structure where the load is transmitted through compression. This indicates an aggravation of Perthes’ disease because bone overloading by compression around the proximal part might occur. The FE method developed in this study can be used to estimate the prognosis of the Perthes' disease.

182. The postoperative rehabilitation of lumbar disk patients in the Region of Southern Denmark
Rune Tendal Paulsen, Erik Bergholdt, Mikkel Østerheden Andersen, Rikke Rousing
Sector for Spine Surgery and Research, Middelfart

Background: Following the municipal reform in Denmark in January 2007, the municipalities gained responsibility for the postoperative rehabilitation. In the Region of Southern Denmark this task were decentralized to a total of 22 municipalities implying a possible risk for considerable variation within the legal framework. An observational study was needed to clarify the rehabilitation programs across the region.
Purpose / Aim of Study: This study elucidates the post-surgical rehabilitation programs of patients with lumbar disk herniation in the 22 municipalities of the Region of Southern Denmark and furthermore performs a statistical analysis of the patient reported outcome measures 1 year after surgery.
Materials and Methods: 22 Physiotherapists answered a questionnaire regarding visitation, methods of training and their general rehabilitation offer. 368 operated patients were linked with zip codes and the different municipalities were then compared with parameters as ODI, EQ-5D and sick leave time.
Findings / Results: Patient reported outcome measures showed no statistical difference in ODI, EQ-5D or sick leave time at 1 year follow up across the 22 municipalities. Rehabilitation programs across the region were comparable upon several factors. The questionnaire revealed potential for improved cooperation between hospitals and rehabilitation centers.
Conclusions: Rehabilitation is broadly similar and patient outcome after 1 year does not differ across the 22 municipalities. Generally all municipalities requests better cooperation between hospital and rehabilitation unit to insure the best patient treatment. Further studies should focus on the effect of rehabilitation and thus generate evidence on this topic.

183. Can older patients survive 8 hours spine reconstruction surgery for degenerative scoliosis?
Jens Egebjærg Rye Svendsson, Valancius Kestutis
Department of Orthopedic surgery, Aarhus University Hospital

Background: Adult scoliosis is one of the most challenging spinal disorders defined as a spinal deformity in a skeletally mature patient. Degenerative, or de novo, scoliosis is usually seen in elderly adults over the age of 60. In selected patients surgery is an effective treatment; however, it is associated with significant risks and major complications.
Purpose / Aim of Study: To analyze and compare perioperative and in-hospital complications and challenges in to patients groups (older and younger) treated for adult degenerative scoliosis.
Materials and Methods: Operations between 01/2003 and 12/2013 were reviewed. Inclusion: degenerative scoliosis; age >40 years; no scoliosis surgery previously; cranial fixation point in the thoracic region, caudal fixation point in the iliac bones; one stage procedure. Patients divided in two groups: age <65 and ≥65. Groups were compared in terms of demographics, admission, per operative data and in-hospital complications.
Findings / Results: 26 patients met inclusion criteria. Group 1, age <65: 12 patients (mean age 57, 43-65). Group 2, age ≥65: 14 patients (mean age 72, 66-81). Operation time: Group 1 - 8.7h ±2.2, Group 2 - 8.2h ±1.9. Perioperative bleeding: 1.7±1.3 and 1.8±0.7 L respectively. No perioperative complications in Group 1, while in Group 2 two patients experienced complications. Average stay in post anesthesia care unit: Group 1 - 1,7 (range 1-5), Group 2 - 1,6 (range 1-4) days. Postoperative general complications: Group 1 - 4 patients, Group 2 – 7. Hospitalization days: Group 1 - 11 (range 7-23), Group 2 - 11 (range 6-18). Two patients from Group 1 needed transfer for further medical treatment, while in Group 2 only one.
Conclusions: We were not able to show increased risk for perioperative complications among older people operated for adult degenerative scoliosis compared to younger population. Thou number of postoperative general complications was slightly higher.

184. The EOS imaging system: Workflow and radiation dose in scoliosis examinations
Bo Mussmann, Stig Jespersen, Trine Torfing
Department of Radiology, Odense University Hospital; Department of Orthopedic Surgery, Odense University Hospital

Background: The EOS imaging system is a biplane slot beam scanner capable of full body scans at low radiation dose and without geometrical distortion. It was implemented in our department primo 2012 and all scoliosis examinations are now performed in EOS. The system offers improved possibility to measure rotation of individual vertebrae and vertebral curves can be assessed in 3D. Leg length Discrepancy measurements are performed in one exposure without geometrical distortion and no stitching. Full body scans for sagittal balance are also performed with the equipment after spine surgery. Purpose
Purpose / Aim of Study: The purpose of the study was to evaluate workflow defined as scheduled time pr. examination and radiation dose in scoliosis examinations in EOS compared to conventional x-ray evaluation.
Materials and Methods: The Dose Area Product (DAP) was measured with a dosimeter and a comparison between conventional X-ray and EOS was made. The Workflow in 2011 was compared to the workflow in 2013 with regards to the total number of examinations and the scheduled examination time for scoliosis examinations.
Findings / Results: DAP for a scoliosis examination in conventional X-ray was 185 mGy*cm2 and 60.36 mGy*cm2 for EOS. The scheduled time for scoliosis was 15 minutes in conventional X-ray which remained unchanged after implementation of EOS. The number of scoliosis examinations has increased from 396 to 1.145 since the implementation.
Conclusions: The radiation dose for a scoliosis examination in EOS can be reduced to approximately 30 % of the radiation dose in conventional X-ray. The increased number of scoliosis examinations is related to increased referral and not due to optimized workflow.

185. Stand-alone XLIF; 22 Consecutive patients with degenerative scoliosis and foraminal stenosis a 2 year follow-up
Emil Hansen
Sector for Spine surgery and Research, Middelfart Hospital

Background: The extreme lateral approach to the intervertebral spaces in the lumbar and thoracic spine is a procedure developed to allow a larger footprint cage to be inserted when performing spondylodesis. In the litterature not many studies have been made to investigate the role of the cage as a stand-alone option for degenerative scoliosis. While the patients often are fragile and with poor bone quality, a single surgical option, preserving the posterior structures, could be beneficial.
Purpose / Aim of Study: The purpose of the study is to evaluate the complication rate and clinical/radiological results in DS patients undergoing spondylodesis with a XLIF stand-alone procedure
Materials and Methods: 22 consecutive patients with DS, underwent surgery with the XLIF stand-alone procedure, follow-up 24 months. Validated clinical outcome scores were collected preoperatively, at 1 and 2 years. Complications were recorded.
Findings / Results: 22 patients with a mean age of 65 (48-81) underwent surgery on 49 levels (1-4) between L1-L5. Visual Analog scores for leg pain improved from 59,4-34,9 (P<0,05) and back pain from 59,1-36,8 (P<0,05). EQ5D scores improved from 0,29-0,62 (P<0,05). 7 patients (31,8 %) underwent revision surgery. Osseous fusion was obtained in 53% of the treated levels at 1 year. Anterior thigh pain was recorded in 12 patients postoperatively but only 2 had consistent sypmtoms at 1 year follow-up.
Conclusions: The XLIF stand-alone procedure is a relatively safe procedure compared with other surgical alternatives as ALIF and PLIF. Our results show a significant improvement in clinical outcome scores during 2 year follow-up. Stand alone XLIF should only be advised for single-level and only mild deformity. In most cases we recommend posterior instrumentation.

186. Early surgical stabilization of rib fractures using a minimally invasive procedure: a pilot study
Kiran Anderson, Jesper RAvn, Henrik Eckardt
Ortopædkir. afd. , Rigshosptialet; Thoraxkir. afd. , Rigshosptialet; Ortopædkir. afd., Rigshospitalet

Background: In spite of considerable development in surgical fracture treatment, most patients with rib fractures are still treated non-operatively, although the respiratory consequences of rib fractures may have severe impact on the prognosis after severe trauma. Recently, a number of studies have suggested that a more active approach may decrease the number of days on ventilation as well as reducing long-term pain in these patients.
Purpose / Aim of Study: The purpose of the present study was to report our initial experience with early surgical stabilization using a minimal invasive procedure of open reduction and internal fixation of multiple rib fractures.
Materials and Methods: 12 consecutive patients received in our level 1-traumacenter with one of the following inclusion criterias were operated: flail chest with at least two rib fractures on two adjacent ribs or four adjacent dislocated rib fractures. The basic principles were: A. No osteosyntesis of costa # 1, 2 or 3. B. Operative fixation of only dislocated ribs. In ribs with multiple fractures only one fracture was stabilized. C. Small incisions with minimal dissection of muscle tissue.
Findings / Results: None of the patients had postoperative infections, seromas or wound problems. Skin incisions were 10-15 cm. The average number of costae fixated was 3. Postoperation time in ICU averaged 2,8 days. Postoperative number of days on assisted ventilation averaged 1,16 days. Total number of admission days postoperatively averaged 9,6 days. Lung function at 3 month was equal to background population.
Conclusions: Rib fracture stabilization is a safe procedure that can be performed with small incisions, without transection of muscles and with low morbidity. The intraoperative impression is that operative fixation provide sufficient stabilization for unstable chestwalls and provides a normal lung function.

187. Open showering of external ring fixators in combination with occlusive pin care. A prospective study of infection rate.
Mykola Horodyskyy, Søren Kold, Pernille Bønneland, Anne Mette Pedersen, Juozas Petruskevicius
Department of Orthopedic Surgery, Aalborg University Hospital

Background: Pin site infection is a common complication in patients treated with external ring fixation. At our institution prophylactic pin care includes occlusive pin site dressings and bah care with a covered frame. However, patients have a wish for showering without the need for covering the frame.
Purpose / Aim of Study: Prospective study of deep pin-site infection rates in patients allowed showering without covering of external frame.
Materials and Methods: Open showering was allowed for patients who both had no inflammation at pin-sites and were able of uncovering pin-sites without help. This open care stopped if pin- site inflammation occurred. 32 (20 females, mean age of 54 years) of 143 patients treated with external ring fixation due to tibia fracture from 2011 to 2013 fulfilled inclusion criteria and were prospectively included. We registered overall use of antibiotics, time in frame, number of showers taken during the treatment, rate of complications and re- operations.
Findings / Results: All fractures united. Frame was removed after a mean time of 24 weeks (range 13 to 43). Median time from operation to showering was 7 weeks (range 2 to 34). Median number of open showers taken during treatment period was 8 (range 1-32). Pin-site inflammation was observed in 17 patients after they began showering. These patients had to stop showering (for median 4 weeks) and 15 of them needed treatment with antibiotics. Median length of treatment with antibiotics was 15 days (3 to 128). There were 3 patients with deep pin sites infection. Two patients were hospitalized for intravenous antibiotics, and one of them underwent two re-operations because of acute osteomyelitis at the fracture site.
Conclusions: Comparative studies with control group are needed to investigate whether showering of uncovered frames is a risk factor for pin site infection.

188. 1-year follow up after a 3 months training program mean 3 years after THA following a femoral neck fracture
Christina Frölich, Inger Mechlenburg, Sara Birch , Lone Lundager, Torben Baek-Hansen, Maiken Stilling
Orthopaedics, Hospital Unit West; Physiotherapy, Hospital Unit West

Background: Poor gait function and functional capacity may be a limitation for activities of daily living (ADL) even years after displaced femoral neck fracture (FNF). We have formerly shown a 3-months training program initiated 1-7 years after THA to result in increased mobility, muscle strength and walking speed.
Purpose / Aim of Study: To evaluate 1-year results of a 3-months resistance training program
Materials and Methods: 27 patients were invited and followed a 3- months resistance training program in 2013, and 24 participated in a 1 year followup (2 dead, 1 denied). Patient—reported questionnaires regarding function, training frequency and health problems affecting training over the last year, and OHS were collected. Physical activity for 4 days was monitored by an accelerometer, fitted on the right thigh.
Findings / Results: At 1 year 30.5% reported higher level of ADL and 74% had continued the training but at a lower level. 58% were walking outside every day, compared with 71% after 3- months training (p=0.32). 54% walked more than 30 min per walk, compared to 21% after 3-months training (p=0.02). 48% had been sick to degree that had affected their training during the past year. OHS had improved from 32 to 36 since baseline (p=0.02). Activity data showed that patients sat more (p=0.02) and stood less (p=0.02) but walked (p=0.55) the same as after the 3-months training program.
Conclusions: 1 year after a 3-months standardized resistance training program 3 out of 4 patients had continued training exercises, and reported similar walking frequency with increased time per walk. Objective activity data did not support sustained activity on whole day observations but supported maintained walking activity. Almost half of the patients had been immobilised due to comorbidity which may have affected their endurance and the measured total activity.

189. Coagulant preventing drugs in patients with hip fractures
Bjarke Viberg, Lasse Enkebølle Rasmussen
Dept. of Orthopaedic Surgery and Traumatology, Odense University Hospital

Background: Anticoagulants and antiplatelets are widely used in the elderly population and new drugs have emerged on the market. Hip fracture patients often needs major surgery and the national guidelines recommend surgery within 24 hours. Some of the coagulant preventing drugs may increase perioperative bleeding and surgical delay.
Purpose / Aim of Study: To estimate how many elderly hip fracture patients are treated with anticoagulants or antiplatelets.
Materials and Methods: Data on all hip fractures in patients above 60 years old undergoing surgery at Funen were retrieved for the period of 2008 to 2013. The first hip fracture for each patient within the study period was eligible for analysis. Patient id was matched in the prescription database for drug use, which was assessed as the proportion of patients having filled a prescription for an anticoagulant or antiplatelet drug within 120 days prior to their surgery. The following drugs were included: (1) vitamin K antagonists (VKA), (2) new oral anticoagulants (NOAC), (3) ADP-receptor blockers, (4) dipyridamole and (5) low-dose acetylsalicylic acid (ASA).
Findings / Results: 4,253 patients were included in the study. 70.6% were female and the median age were 83.2 (IQR 60.1-88.4). Over the entire study period, 40.3% (n=1,716) had filled a prescription for one or more anticoagulants or antiplatelets. 11.4% had filled more than one drug class. 31.6% had filled a prescription for ASA, 10.2% for dipyridamole, 6.1% for VKA, 3.7% for ADP-receptor blockers, and 0.4% for NOACs. Over the study period, use of VKA and ADP-receptor blockers increased from 4.7% to 8.2% and 2.4% to 6.9% respectively. NOAC was registered in 2011 and the use of NOAC increased from zero to 1.8%
Conclusions: Use of coagulant preventing drugs are common among patients with hip fractures.

190. Impact of timing of soft tissue coverage and antibiotics in outcome of open tibial 2 fractures
Ulrik Kähler Olesen, Rasmus Juul, Christian Bonde, Claus Moser, Henrik Eckardt
Ortopædkirurgisk Klinik U, Rigshospitalet; Ortopædkirurgisk afdeling , Slagelse Hospital; Plastikkirurgisk klinik, Rigshospitalet; MIkrobiologisk afdeling, Rigshospitalet; Department of Traumatology, University Hospital Basel, Switzerland

Background: Treatment of open fractures is complex and somewhat controversial. The purpose of the present study is to add evidence to the management of open injuries to the lower extremity, where tissue loss necessitates using a free flap.
Purpose / Aim of Study: We identify factors for a successful outcome: Avoidance of amputation and infection, achievement of union of the fracture and obtaining tissue coverage over the bone. Our study also evaluates the microbiology of open fractures and suggests the choice of antibiotic prophylaxis for this serious condition
Materials and Methods: From January 2002 to June 2013 we treated 56 patients with an open tibial fracture requiring coverage with a free flap. We reviewed patient records and databases for information on time to coverage, infection, microbiology, amputations, and union of the fracture. Follow-up was minimum one year
Findings / Results: In 45 patients, data was complete. When soft tissue coverage was delayed beyond 7 days, infection rate increased from 27% to 60%. High-energy trauma patients had a higher risk of amputation, infection, flap failure and non-union. Smokers had a higher risk of flap failure and non-union. Most organisms found in the infected wounds of open fractures were resistant to cefuroxime, aminoglycosides and amoxicillin, but sensitive to vancomycin and meropenem.
Conclusions: To our knowledge, our study is unique in its combination of data on timing and microbiology. We conclude that flap coverage within one week remains essential for successful outcome. We suggest antibiotic prophylaxis treatment with vancomycin and meropenem until the wound is covered, in these rare injuries

191. Intraoperative 3D imaging is useful in the operative treatment of displaced calcaneal fractures
Marianne Vestergaard Lind, Henrik Eckardt
Ortopædkirurgisk Klinik, Rigshospitalet; Ortopædkirurgisk Klinik , Rigshospitalet

Background: One goal in the operative treatment of displaced calcaneal fractures is to restore the anatomy of the posterior facet. Conventional fluoroscopes are unable to viaualise the posterior facet.
Purpose / Aim of Study: We used intraoperative CT-scans for 3D- imaging to aid the reduction af fixation of calcaneal fractures and report our results and experiences
Materials and Methods: 62 non-consecutive patients received open reduction and internal plate fixation of displaced calcaneal fractures that were aided by intraoperative CT-scans for 3D imaging.
Findings / Results: The postoperative articular dislocation was 0 mm in 69% of the Sanders type 2 fractures and 57% of hte Sanders type 3 fractures. In 40% of the operations, the intraoperative scan visualised articular steps, screws penetrating joints or being to long, with the possibility of revision before wound closure.
Conclusions: Intraoperative CT-scanning in calcaneal fracture surgery facilitates the reduction and correct placement of plate and screws, leads to good operative results, and obviates the risk for reoperations. Scanning prolongs the operative procedure, but does not increase the infection rate.

192. Ewings´sarcoma of the calcaneus treated by limb sparing surgery with calcanectomy and reconstruction with a composite of an allograft and a vascularised osteocutaneous fibula graft.
Werner Hettwer, Lisa Toft Jensen, Michael Mørk Petersen
Musculoskeletal Tumor Section, Department of Orthopaedic Surgery, Rigshospitalet, University of Copenhagen; Department of Plastic Surgery, Rigshospitalet, University of Copenhagen

Background: Primary malignant bone tumours of the calcaneus are very seldom. Due to poor possibilities to do surgery with wide margins in this region and limited options for reconstruction after calcanectomy many orthopaedic oncologists use amputation as the preferred surgical treatment.
Purpose / Aim of Study: We present two cases of Ewings´sarcoma of the calcaneus treated with limb sparing calcanectomy and reconstruction with a composite of an allograft and a vascularised osteocutaneous fibula graft.
Materials and Methods: Case 1: a girl, almost 6 years old at the time of calcanectomy of the left calcaneous August 7th 2012. Case 2: a girl 16 years old at the time of right calcanectomy October 16th 2013. Both patients received pre- and post- operative chemotherapy because of Ewings ´sarcoma. In both cases removal of the calcaneus was performed using a combined medial and lateral incision. In case 1 a femoral head allograft was fitted to replace the removed calcaneus, and in case 2 a calcaneus allograft was used. In both cases, with the aim of obtaining arthrodesis, the allograft was fixed to the talus and cuboid bone with Acutrak titanium screws. A distally pedicled osteocutaneous flap was used for reconstruction of soft tissue, and a 5-6 cm piece of vascularised fibula bone was fitted into the allograft and fixed using staples.
Findings / Results: Case 1 was allowed weight-bearing in an ankle brace after 3½ months and full weight- bearing with-out brace 8 months postoperatively, when the arthrodesis between allograft and talus was considered healed. Case 2 was allowed increasing weight-bearing in a ROM walker 7 months postoperatively, when the arthrodesis between allograft and talus was considered healed.
Conclusions: Limb sparing calcanectomy was feasible with reconstruction using a composite of an allograft and a vascularised osteocutaneous fibula graft.

193. Pathway Leading To Lower Limb Amputation – a Danish national registry study
Pia Søe Jensen, Klaus Kirketerp-Møller, Nasrin Faqir, Janne Petersen, Ingrid Poulsen, Ove Andersen
Department of Orthopedic Surgery, Clinical Research Centre, University Hospital of Copenhagen, Hvidovre ; Department of Orthopedic Surgery, University Hospital of Copenhagen, Hvidovre ; Clinical Research Centre, University Hospital of Copenhagen, Hvidovre; Department of Neurorehabilitation/TBI Unit, Glostrup Hospital, University Hospital of Copenhagen, Hvidovre

Background: Patients with non-traumatic lower limb amputation are characterised by high age, multiple medical co-morbidities including lifestyle diseases, repeated hospital admissions, need of rehabilitation and a high mortality rate. No papers have described the pathway leading to major lower limb amputations in Denmark.
Purpose / Aim of Study: The purpose of this study was to describe patients’ pathway leading to lower limb amputation in Denmark.
Materials and Methods: A national registry based study. We defined an index amputation as the first Above Knee amputation (AKA), Below Knee Amputation (BKA), Foot or Toe Amputation procedure performed respectively. Our cohort included patients with an index amputation in 2010 or 2011. We included data on demographic, admissions, diagnoses, surgical procedures and medical treatment 14 years prior to the index operation. Data was provided by Statistics Denmark.
Findings / Results: The cohort included 2829 patients with an index amputation. Of these 1010 (36 %) patients had an AKA, 752 (26%) had a BKA, 986 (35 %) had a foot or ankle amputation, and 81 (3 %) patients had a toe amputation. In the cohort 63 % was men with a mean age of 71. At time of index amputation the mean age for women was 74 and for men 68 years. Furthermore, 71 % were retired and the majorities (53 %) were living alone. For patients with AKA and BKA 89 % and 86 % respectively, had no prior lower limb a
Conclusions: A large group of patients begins their pathway with a major amputation which indicates that patients were waiting too long to seek medical advice or that they were without symptoms for a long time. Further analysis of data will show the distribution of comorbidities such as diabetes and arteriosclerosis and use of medical services will provide more information about different pathways leading to lower limb amputation.

194. Clinical outcome after CT-guided radiofrequency ablation of osteoid osteoma. Long-term follow up in 52 patients.
Morten Knudsen, Andreas Riishede, Arne Lücke, John Gelineck, Johnny Keller, Thomas Baad-Hansen
Department of Orthopaedic Surgery, Aarhus University Hospital; Department of Radiology, Aarhus University Hospital

Background: Osteoid osteoma (OO) is a benign bone tumor characterized by a small central nidus with a high production of prostaglandins in the nidus resulting in characteristic clinical symptoms of constant local pain, most severe at night. Most commonly OO occurs in children and young adults. Surgical excision of the nidus has previously been the first- choice treatment. CT-guided radiofrequency ablation (RFA) has been introduced as a safe, minimal invasive treatment of OO.
Purpose / Aim of Study: The aim of this study was to evaluate the long-term clinical outcome after CT-guided RFA in patients with OO performed from 1998 to February 2014 at Aarhus University Hospital.
Materials and Methods: The study population included 52 patients with typical clinical history and radiologically confirmed OO who received CT-guided RFA treatment. Clinical outcome was evaluated based on patient questionnaire and medical record review.
Findings / Results: Response rate was (52/60) 87% Clinical success of pain relief after the first RFA treatment was found in (46/52) 88% of the patients and after re-RFA clinical success of pain relief in (51/52) 98% of the patients. One patient had an open resection made after RFA. No major complications occurred and four patients had minor complications in terms of small skin burn, minor skin infection and hypoesthesia at the entry point. (50/52) 96% of the patients reported to be “very satisfied” with the RFA treatment.
Conclusions: CT-guided RFA is a safe and effective treatment, with good clinical results and a high patient satisfaction rate with strong reduction of pain and improvement in quality of life. RFA should be the treatment of choice for most OO.

195. Extended Antibiotic Prophylaxis is associated with Low Rate of Infection after Tumor Resection and Endoprosthetic Reconstruction involving the Proximal Femur
Werner H. Hettwer, Thea B. Hovgaard, Peter Horstmann, Thomas A. Grum-Schwensen, Michael M. Petersen
Department of Orthopedics, Rigshospitalet, University of Copenhagen

Background: Endoprosthetic reconstruction after tumor resection involving the proximal femur is associated with a substantially higher risk of periprosthetic joint infection (PJI), with reported rates around 10% in a recent systematic review. The optimal duration of antibiotic prophylaxis for this patient population is unknown.
Purpose / Aim of Study: To determine the rate of infection and other complications after tumor resection and endoprosthetic reconstruction at our institution.
Materials and Methods: We performed a retrospective review of all adult patients who underwent endoprostetic reconstruction of the proximal femur after tumor resection for primary bone sarcomas (n=11) or metastatic bone disease (n=113) in our department from 2010 to 2013. We found 118 patients (F/M =64/54) with a mean age of 65 years (range 16 – 92) received a total of 124 implants.
Findings / Results: We identified 18 major complications (15%): 12 dislocations (10%), 5 PJI (4%), one mechanical complication (1%) and one local recurrence (1%) resulting in a total of 23 revision procedures. Two- stage revision was performed sucessfully in 3 of the 4 patients with infection. Ten patients with instability underwent successful stabilisation by implantation of a constrainment device and did not experience further episodes of dislocation.
Conclusions: Compared to the published average we found a low infection rate (4 %) after tumor related enoprothetic reconstruction. Given the very low infection rate identified in our patients, we see no reason to change our current practice of extended antibiotic prophylaxis for high risk patients until very convincing evidence to the contrary becomes available.