Session 14: Foredragskonkurrence

Fredag den 25. oktober
13:00 – 14:30
lokale: Stockholm/Copenhagen/Helsinki/Oslo
Chairmen: Ole Rahbek / Steen Lund Jensen

132. Prognostic Factors in 1065 Adult Non-Metastatic Soft Tissue Sarcoma: a Population-Based Cohort Study
Katja Maretty-Nielsen, Ninna Aggerholm-Pedersen, Akmal Safwat, Peter Holmberg Jørgensen, Alma Pedersen, Johnny Keller
Department of Experimental Clinical Oncology, Aarhus University Hospital; Department of Oncology, Aarhus University Hospital; Department of Orthopaedic Surgery, Aarhus University Hospital; Department of Clinical Epidemiology, Aarhus University Hospital

Background: Previous registry-based studies of soft tissue sarcoma (STS) have identified a number of possible prognostic factors; however the majority of these include highly selected populations, with unclear validity of data, and insufficient statistical methods.
Purpose / Aim of Study: The aim of this study was to identify prognostic factors in a validated, population- based 30-year series of STS treated at a single institution, using a more advanced statistical approach with cubic spline regression and competing risk.
Materials and Methods: Between 1979 and 2008, 1065 adult patients were treated at the Sarcoma Centre of Aarhus University Hospital for a non- metastatic STS in the extremities or trunk. The endpoints were local recurrence and disease-specific mortality. Prognostic factors were analyzed uni- and multivariately using a competing risk proportional hazard model, with inclusion of continuous variables as cubic splines.
Findings / Results: It was proper to analyze age, duration of symptoms, and tumor size as cubic splines. The 5-year local recurrence rate was 15%. Independent favorable prognostic factors for local recurrence were small size, intracompartmental location, grade 1, wide/radical excision, duration of symptoms <13 months or >30 months (vs. 3 months), and radiotherapy. The 5-year disease- specific mortality rate was 23%. Important favorable prognostic factors for disease- specific mortality were small size, subcutaneous location, grade 1, wide/radical excision, and radiotherapy.
Conclusions: It is important to use continuous non-linear variables and competing risk analyses in prognostic studies. In this population-based, validated series of adult, non-metastatic STS; duration of symptoms, tumor size, depth, compartmentalization, grade, surgical margin, and radiotherapy were important independent prognostic factors.

133. Radiostereometric analysis (RSA) of two MoM cups, 2 year results from a randomized clinical trail (RCT)
Jeannette Penny, Ming Ding, Ole Ovesen, Jens Erik Varmarken, Søren Overgaard
Dept. of orthopeadics, OUH/Næstved

Background: Continuous migration measured by RSA is a predictor for failure. The ASR resurfacing implant was withdrawn due to excessive failure rates but showed initial femoral component stability.
Purpose / Aim of Study: We aimed to investigate the initial implant stability for the cup as an explanation for the high revision rate, and to compare it to another metal on metal cup.
Materials and Methods: 36 patients with primary OA from a RCT received either an ASR (n=19) or an M2a-Magnum Cup (n=17) without markers. RSA images were obtained within 3 days of surgery, at 8 w, 6 m, 1 and 2 years. A model based RSA system calculated migration. ANOVA analysed movement over time as well as difference between implants
Findings / Results: Initial movement was noted, especially for the M2a-Magnum cup, where the 2 year mean (sd) X translation was -0.307 (0.53)mm (p = 0.01), Y translation was 0.282 (0.36)mm (p < 0.001) and Z translation was -0.343 (0.63)mm p = (0.03). After 2 years the ASR cup displayed a mean X translation of -0.115 (0.60) mm (p = 0.82), Y translation of 0.075 (0.14) mm (p = 0.01) and Z translation of 0.438 (0.88)mm (p = 0.04) The implants had a similar pattern for X and Y with slightly more movement for M2a-Magnum in the X translations (p< 0.01) On the Z axis the implants displayed movement in opposite directions (p=<0.001). At two years 4 ASR and 5 M2aMagnum migrated above 1 mm in one axis.
Conclusions: The early migration of both cups were low - for the ASR implant particularly at the Y axis, where the mean 0.075 mm is well below the limit of 0.2mm suggested as an acceptable threshold. The M2a- Magnum cup has migration rates just above that, but longer clinical follow up is needed to establish if this cup has greater risk of revision. Continuous migration is not likely to explain failure of neither the cup nor the femoral side of the ASR hip.

134. Preoperative effects of progressive individualized explosive-type resistance training in patients with osteoarthritis scheduled for total hip arthroplasty (THA) -a prospective randomized controlled trial (RCT)
Andreas E B Hermann, Anders Holsgaard-Larsen, Bo Zerahn, Steen Mejdahl, Søren Overgaard
Department of Orthopaedic Surgery, Herlev University Hospital; Orthopedic Research Unit, Department of Orthopaedic Surgery and Traumatology , Odense University Hospital; Department of Clinical. Physiology and Nuclear Medicine, Herlev University Hospital

Background: Hip Osteoarthritis (OA) is associated with pain, functional deterioration and loss of muscle function. Progressive explosive-type resistance training (RT) is effective in improving muscle strength and functional performance in healthy elderly. In hip OA patients the effects prior to THA remain unknown.
Purpose / Aim of Study: To investigate the effect of RT in hip OA patients scheduled for THA on i) self-reported outcomes and ii) muscle function, physical function and body composition.
Materials and Methods: RCT. Eighty patients (age 70.4 ± 7.6 years, BMI 27.8±4.6, 70% females (n=52)) diagnosed with hip OA and scheduled for primary THA were randomized into two groups: 1) The intervention group (IG) received supervised RT twice a week for 10 weeks; 4 leg/hip exercises of 3 series each (~80% of 1 repetition maximum). 2) The control group (CG) received ‘care as usual’. Outcomes: Primary; Hip Osteoarthritis Outcome Score (HOOS), secondary; leg extension power, functional tests, body composition (DXA). Adjusted between group changes from baseline to follow-up (2-5 days prior to surgery) were analyzed as intention-to-treat using multilevel regression.
Findings / Results: For HOOS ADL the IG scored 9.7 points 95%CI [4.3;15.2] higher compared to CG at follow-up (p=0.001). For the remaining 4 HOOS subscales IG performed significantly better than CG (p<0.03). IG had higher leg muscle power (p<0.0001); better function (gait speed, stair-climb, sit- stand) (p<0.0001) and increased lean body mass (p=0.013) compared to CG. RT was well accepted in IG
Conclusions: For the first time it is shown that Hip OA patients scheduled for THA can comply with RT and significantly improve self-reported function and pain and muscle function, functional capacity and lean body mass. The present intervention prior to surgery holds promise for an optimized post- surgery rehabilitation

135. Is 8 weeks supervised early progressive resistance training after unicompartmental knee arthroplasty more effective than home based exercise?
Peter Bo Jørgensen, Søren Bie Bogh, Kjeld Søballe, Henrik Sørensen, Anders Odgaard, Inger Mechlenburg
Orthopaedic Research Unit, Aarhus University Hospital; Department of Sports Science, Aarhus University; Orthopaedic Department, Aarhus University Hospital

Background: 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.
Purpose / Aim of Study: Purpose: To investigate the effect of early progressive resistance training (PRT) after UKA
Materials and Methods: Materials and Methods: 53 patients (26 male), 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). The PRT was initiated within the first week after UKA and performed 2/week for 8 weeks in training machines (relative load from 15-8 Repetition Maximum). Before and 2 months after UKA leg muscle power, spatio-temporal parameters, functional capacity and Knee injury and Osteoarthritis Outcome Score (KOOS) were measured.
Findings / Results: Results: 8 patients dropped out (6 PRT). Patients in the PRT group participated in mean 11 out of 16 training sessions. Max leg power improved 0.24 [0.05;0.43] W/kg in the PRT group and was unchanged -0.01 [-0.23;0.26] W/kg in the HE group. Self-selected walking speed increased for PRT 0.6 [0.42;0.67] km/h and for HE 0.5 [0.17;0,79]km/h. 6 min walking speed increased for PRT 0.35 [0.09;0.61] km/h and for HE 0.27 [-0.20;0.75] km/h. Asymmetry of walking pattern was equal to preoperative values for both groups. Pelvic rotations in step test increased significantly for both groups. KOOS increased in all sub- scores for both groups (p=0.53-0.92). For all the mentioned tests there was no differences between the groups (p= 0.13-0.97) .
Conclusions: Conclusion: We found no additional effect of early PRT compared to HE in this patient group when tested 8 weeks after surgery. However, adherence to PRT was fairly low and 20% dropped out.

136. 3 Year Multicenter RSA evaluation of vitamin E diffused highly cross-linked polyethylene liners and acetabular cup stability
Nanna H. Sillesen, Audrey Nebergall, Poul T. Nielsen, Mogens B. Laursen, Anders Troelsen, Henrik Malchau
Harris Orthopaedic Laboratory, MGH + Department of Orthopedics, Hvidovre Hospital. , Massachusetts General Hospital, Boston, MA, USA. + Copenhagen University Hospital, Hvidovre, Denmark; Harris Orthopaedic Laboratory, MGH, Boston, Massachusetts General Hospital, Boston, MA,; Department of Orthopaedics, Aalborg University Hospital, Aalborg University Hospital, Aalborg, Denmark; Department of Orthopedics, CORH, Hvidovre Hospital, Copenhagen., Copenhagen Univeristy Hospital, Hvidovre, Denmark; Harris Orthopaedic Laboratory, Massachusetts General Hospital, Boston, MA,

Background: Vitamin E diffusion into highly cross-linked polyethylene (VEPE) is a method for enhancing long-term oxidative stability of hip arthroplasty liners. Early clinical outcome is important to document that there are no detrimental effects of new developments.
Purpose / Aim of Study: The purpose of this study was to evaluate in vivo wear properties of VEPE and the stability of a porous-titanium coated acetabular cup using Radiostereometric Analysis (RSA).
Materials and Methods: 144 patients were recruited into a prospective 5 years RSA study at 2 centers. All patients received porous-titanium coated cups and either VEPE or non-vitamin E medium cross-linked liners (XLPE). Cobalt- chrome or ceramic femoral heads were used, 32mm or 36mm. At Center1 the acetabulum was under reamed by 1 mm and at Center2 it was reamed size-to-size.
Findings / Results: There was no statistically significant difference (p=0.203) in femoral head penetration into the VEPE liners at 3 years comparing the 32mm metal heads (-0.002±0.02mm) with the 32mm ceramic heads (-0.04±0.06mm). There was no difference (p=0.087) in head penetration into VEPE liners at Center1 compared with XLPE liners at Center2 (0.02±0.05mm); however there was significantly less wear in VEPE than XLPE liners at 3 years at Center2 (p=0.017). One year median proximal cup migration at Center1 (0.14±0.03mm) was significantly lower than at Center2 (0.38±0.06mm) (p=0.001). Median cup migration at Center1 remained stable at 3 years (0.15±0.05mm); however Center 2 showed significant continual migration at 3 years (0.45±0.09mm) (p≤0.002).
Conclusions: This study provides the first multicenter in vivo wear measurement of VEPE liners using RSA. The 3year follow-up shows VEPE results indicating low liner penetration regardless of head material or size and low amount of early cup-movement.

137. Collagen conduit vs. microsurgical neurorrhaphy Two year follow up of a prospective blinded clinical and electrophysiological multicenter RCT
Michel E.H. Boeckstyns, Allan Ibsen Sørensen, Joaquin Fores Vineta, Birgitta Rosén, Xavier Navarro, Christian Krarup
Clinic for Hand Surgery , Gentofte Hospital; Clinic for Hand Surgery, Rigshospitalet; Orthopedic Surgery, Hospital Clínic, University of Barcelona; Hand Surgery, Skåne University Hospital, Malmö; , Institute of Neurosciences of the Independent University of Barcelona; Neurophysiology, Rigshospitalet

Background: Currently there are no randomized studies or studies reporting on motor recovery after nerve repair with collagen conduits in humans
Purpose / Aim of Study: Hypothesis: Collagen Nerve Conduits, for repair of traumatic nerve lesions in humans, is associated with reinnervation and recovery of sensory and motor functions that are at least equivalent to conventional repair (direct suture or nerve grafting).
Materials and Methods: In a prospective randomized trial, acute section of the ulnar or median nerves were repaired with a collagen nerve conduit or with conventional microsurgical techniques. Electrophysiological tests and hand function using a standardized clinical evaluation instrument were compared after 12 and 24 months using a one-way and a two-way ANOVA with repair type and nerve type as factors.
Findings / Results: 44 total nerve lacerations were included. There were no infections, extrusions or other local adverse reaction. 32 patients with 33 nerve lesions attended the 24- month follow-up. There were no differences in electrophysiological tests.When compared at 12 and 24 months there was a general further recovery of both motor conduction parameters (P<0.01) and sensory conduction parameters (P<0.05). At one-way ANOVA there was no difference between sensory, discomfort or total hand function scores. The two-way ANOVA test showed significant differences in clinical motor recovery according to nerve (median doing better than ulnar).The type of repair in itself had no influence on sensory or motor function after 24 months.
Conclusions: The Collagen Nerve Guide Conduit, for repair of traumatic nerve lesions in humans is associated with reinnervation of the denervated organs and recovery of sensory and motor functions that are equivalent to conventional repair, but it was not superior.The procedure is safe in the distal forearm.

138. Cup design is an important factor in survival of trapeziometacarpal total joint trapezium components.
Haider Ghalib Majeed, Torben Bæk Hansen
Department of Orthopedic Surgery, Regional Hospital Holstebro

Background: Cup failure is a recognized problem in total trapeziometacarpal (TM) joint prosthesis, probably due to several individual factors. The cup design may have an important effect on the primary pressfit fixation and secondary bony fixation of non-cemented cups influencing on cup migration and overall prosthesis survival.
Purpose / Aim of Study: The purpose of this study is to compare two different designs in non-cemented cups and the possible effect on prosthesis survival, revision rates and overall patient’s satisfaction.
Materials and Methods: In a prospective study, two consecutive groups of patients were included. The two groups were operated with two completely different cup types and designs (cup with collar versus cup without collar). The DASH score, hands grip strength, and radiological control was measured in predefined time points (preoperative, 3, 12, and 24 months postoperative). Twenty-two patients were included in each group. First group (8 males/14 females) were operated with MOTEC prosthesis (cup with collar). The mean age was 61 (45-73). The second group (5 males/17 females) were operated with Elektra prosthesis (cup without collar). The mean age was 59 (46-74).
Findings / Results: After 24 months the revision rate in the MOTEC group was 41% (9/22), versus 0% (0/22) in the Elektra group (p-value= 0.02). Adding radiological loosening after 24 months, 13 cups in the MOTEC group were revised or radiologically loose versus 1 cup in the Elektra group (p<0.01). There were no significant differences in clinical results between the two groups in the patients without radiological loosening.
Conclusions: Cup design has a significant role in the overall prosthesis survival and overall revision rate after 24 months. The MOTEC cup design seems to be a failure compared to the Elektra cup.