Abstract
Aims: To compare the lateral vs medial approaches for TKRs in valgus knees. Methods: 67 knees (59 patients) with a valgus deformity of more than 10° suitable for total knee replacement were randomised to two different approaches. One group (36 knees) had their knees replaced by the standard medial para-patellar approach, whilst the other (31 knees) received a modified lateral approach (without an osteotomy of the tibial tubercle and with repositioning of the contracted vastus lateralis). Both groups were well matched with a predominance of females and mean age of 66.2 years. Average follow up was 28 months. Patients were assessed both pre and post operatively by the HSS (Hospital for Special Surgery) and Oxford knee scores, radiologically by weight bearing AP and lateral radiographs and by patient satisfaction scores on a scale of 10. Results: The mean pre operative HSS and Oxford scores for the medial group were 36.0 and 46.6 respectively and for the lateral group were 35.3 and 46.3 respectively. The mean post operative HSS and Oxford scores for the medial group were 77.4 (mean improvement of 41.4 points) and 26 respectively and for the lateral group was 81.2 (HSS score, mean improvement of 45.9 points) and 26.8 (Oxford score). 79.4% of patients in the medial group and 88% of patients in the lateral group showed good to excellent results (using the HSS scoring system)At two years none of the knees were radiologically loose, mal aligned or showed any evidence of an avascular necrosis. Average patient satisfaction on a scale of 10 was 7.9 for the medial group and 8.5 for the lateral group. One patient reported no relief of pain and an acute limitation of function at two years. She suffers from severe Parkinson’s disease and disabilities arising from multiple joint pathologies. There was no incidence of an early/ late infection. Pain relief, range of motion and deformity correction were comparable in the two groups. Conclusions: Our findings so far have shown that at an average of two and half years there seem to be better results in the group which had a lateral approach. However, this was not statistically significant. There are certain operative difficulties that can be overcome by using the lateral approach. Also, the incidence of the requirement of a stage II lateral release (release of the fibular collateral ligament and the popliteus) was found to be lower in the knees approached laterally. There was no need for any type of prosthetic constraint. Only one case of post operative valgus instability was seen in a lady suffering from severe Parkinsonism. This is a prelimnary report on a study now containing 97 patients.
Theses abstracts were prepared by Professor Dr. Frantz Langlais. Correspondence should be addressed to him at EFORT Central Office, Freihofstrasse 22, CH-8700 Küsnacht, Switzerland.
