Good functional results of distal femoral opening-wedge osteotomy of knees with lateral osteoarthritis.

Purpose: To evaluate the time-dependent functional outcome of patients with lateral knee osteoarthritis with increased valgus treated with lateral opening-wedge osteotomy to shift the load from the lateral to the medial compartment of the knee.

Methods: Twenty-four consecutive patients with lateral knee osteoarthritis were treated with distal femoral opening-wedge varus osteotomy stabilized with the Puddu plate and bone transplantation. The mean age of the patients was 48 years (CI 40.3-55.7, range 31-62). The patients were evaluated by the Knee Injury and Osteoarthritis Outcome Score (KOOS) preoperatively and at 3 and 6 months, 1, 2, 5 and 10 years post-operatively. The knee osteoarthritis was graded according to the Kellgren-Lawrence radiological scoring system. The mean follow-up time was 7.9 years (CI 6.8-9.0, range 4.0-10.2).

Results: The mean angular correction measured on pre- and post-operative radiographs was 9.6° (CI 7.7°-11.5°, range 4°-20°). All osteotomies healed. KOOS increased significantly during the first year by 28-122 % beyond the preoperative values for all the five subscores. This improvement remained at 10-year follow-up for those with surviving osteotomy. Six knees were converted to total knee arthroplasty (TKA) mean 6.4 years (CI 3.3-9.6, range 4.0-11.8) post-operatively. The osteotomy survival rate at 5 years was 88 % and at 10 years 74 %. The preoperative osteoarthritic grade did not increase significantly during the follow-up period, but was significantly correlated (r = -0.49), P = 0.019 to the KOOS subscore symptoms at the 2-year follow-up.

Conclusion: Distal femoral opening-wedge osteotomy for lateral knee osteoarthritis resulted in good functional recovery after 1 year and favourable midterm results. It may be a good treatment option for middle-aged patients with valgus knees and lateral osteoarthritis in order to prevent or postpone TKA.

Level Of Evidence: IV.