High tibial valgus osteotomy in unicompartmental medial osteoarthritis of the knee: a retrospective follow-up study over 13-21 years.

PURPOSE: High tibial osteotomy is a well-established method for the treatment of medial unicompartmental osteoarthritis of the knee.
METHODS: We analysed retrospectively the long-term outcome of open and closing wedge valgisation high tibial osteotomies. Out of 71 patients, 54 (76%) were available for the study. Survival rates and the influence of the osteotomy type were investigated. Secondary outcome measures were the course of radiological leg axis and osteoarthritis as well as score outcomes.
RESULTS: During a median follow-up of 16.5 years (IQR 14.5-17.9; range 13-21), 13 patients (24%) underwent conversion to total knee arthroplasty; the other 41 patients (76%, survivor group) were studied by score follow-up as well as clinical and radiological examinations. Osteotomy survival was of 98% after 5 years, 92% after 10 years and 71% after 15 years. Comparison between open and closing wedge high tibial osteotomy showed no significant difference in survival and score outcome. The median Visual Analogue Score (VAS) was 0 (IQR 0-1; range 0-4), the Satisfaction Index was 80% (IQR 63-89; range 30-100), the median Knee Injury and Osteoarthritis Outcome Score was 71 (IQR 49-82; range 9-100) and the median Western Ontario and McMaster Universities Osteoarthritis index was 84 (IQR 66-96; range 9-100). Radiological evaluation showed only a slight progression of the degree of osteoarthritis following the Kellgren and Lawrence classification. In each case, the axis passed through the healthy compartment or at least through the centre of the knee.
CONCLUSION: Open and closing wedge high tibial osteotomies are a successful choice of treatment for unicompartmental degenerative diseases with associated varus in active patients. Survival of both techniques is comparable in our series and is associated with low pain scores, high satisfaction and high activity levels of the survivors.