Postersession II

Onsdag den 22. oktober
11:00 – 12:00
Lokale: Stockholm/Copenhagen
Chairmen: Thomas Jakobsen / Kjeld Søballe

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.