Paper #142 Early complications after high tibial osteotomy - a comparison of two techniques (open vs. closed wedge)

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ABSTRACTS

vanced models. Articular cartilage degeneration was significant only in the MFC with advanced (Grade IV) arthritis vs early (Grade I-III) changes in the KOOS model, and for the LFC was significant in both early and advanced in the KOOS model and in sports/recreation function, quality of life and overall scores. Conclusions: The overall functional outcome after operative knee arthroscopy as assessed by validated questionnaires is most highly correlated by articular cartilage status, especially patellofemoral arthritis, as well as gender with males having statistically significant worse outcomes scores than females. Meniscal treatment did not significantly affect scores at follow-up. The results of this study may assist the counseling of patients regarding expectations of functional outcomes following knee arthroscopy. Paper #142 Early Complications After High Tibial Osteotomy – A Comparison Of Two Techniques (Open Vs. Closed Wedge). Thomas W. Patt, Presenter, Ziekenhuis Hilversum, Hilversum, Netherlands, Mirjam Y. Kleinhout, Amsterdam, Netherlands, Robert G. H. Albers, Huizen, Netherlands, Harm M. van der Vis, Hilversum, Netherlands Aim of the study: To compare two different techniques of high tibial osteotomy (HTO) (open wedge PUDDU vs. closed wedge AO-L-plate), with special interest in complications (rate of pseudoarthrosis, infections, re-operations, loss of correction angle). Material and Methods: Between March 2000 and December 2000 we treated 40 consecutive patients suffering from med. gonarthrosis with valg. high tibial osteotomy (HTO) and followed them prospectively. Out of this group in 50% the open wedge technique (PUDDU) was used, the other patients were treated with the “conventional” technique (AO-L-plate). In the open wedge group the wedge defect was filled with tricalcium phosphate. There were 21 female and 19 male patients with an average of 52 years of age (range 30-75). (P : 52.2, range 30-75, T : 51.9, range 32-63). 16 right (P: 7 / T: 9) and 24 left knees (P: 13 / T: 11) were treated. At an average of 11 months (range 3 - 24 mths) all patients were followed. A visual analog scale was noted (pain and quality of living), standard x-rays (ap and lateral) were taken preoperatively as well as at follow-up and complications were noted. Results: In total 25 complications in 15 patients were noted. In the PUDDU group 11 patients (55%) suffered from 19 complications, versus four patients (20%) from six complications in the AO-group. Eight tibial non unions (P: 35% / T: 5%), three fibular non unions

(P: 0 / T: 15%) and three infections (P: 10% / T: 5%) occurred. Furthermore three times loss of correction (P: 15% / T: 0) and six times material failure (P: 30% / T: 0) complicated the post-operative period, as well as loosening of material which was found in two cases (P: 5% / T 5%). These complications led to re-operations in 15% of the total patient group (P: 15% / T: 15%). Despite the fact, that most of the patients had improved postoperatively regarding pain and quality of living, the percentage of complications in the group of patients treated with the open wedge technique (PUDDU) was significantly higher regarding tibial non union, loss of correction and material failure. Conclusion: Even though both techniques (conventional L-plate and PUDDU open wedge) are well established, the substitution of the wedge defect with tricalcium phosphate bone in the PUDDU group seems to lead to a higher complication rate. We will adapt our surgical technique in the future and look for a different bone substitute. Further studies have to proof, whether this will lead to satisfactory results. Paper #143 CT Evaluation Of Femoral Component Rotation In TKA: Comparison Of Tibial Axis Method To Transepicondylar Line. Jens Boldt, Presenter, Schulthess Klinik, Zu¨ rich, Switzerland, Urs Munzinger, Zu¨ rich, Switzerland Purpose: Accepted landmarks for determining femoral component rotation in total knee arthroplasty (TKA) include the posterior condyles, Whiteside’s line, arbitrary three to four degrees of external rotation, and transepicondylar axis (TEA). All methods require anatomical identification, which may be variable. The purpose of this study was to radiologically evaluate femoral component rotation (CT analysis) based on a method that references to the tibial shaft axis and balanced flexion tension without identification of femoral anatomical landmarks. Methods: Out of a cohort of 3058 mobile bearing low contact stress TKA, CT scans of 38 randomly selected well functioning TKA were evaluated to determine femoral component positioning. Spiral CT scans of the femoral epicondylar region with four mm cuts were performed to accurately identify medial and lateral femoral epicondyles. Rotational alignment was measured in relation to the transepicondylar axis using CT-implemented software by two independent radiologists. Results: Mean femoral rotational alignment was parallel to the TEA (average 0.3 degrees internal rotation) ranging from six degrees internal to four degrees external