Functional outcome of total knee arthroplasty after high tibial osteotomy.

OBJECTIVE: To evaluate the functional outcome for patients who undergo total knee arthroplasty (TKA) after high tibial osteotomy (HTO). DESIGN: Retrospective matched cohort study. SETTING: University of Toronto affiliated hospital. PATIENTS: Twenty patients who underwent TKA after HTO and 20 matched patients who received a primary TKA. INTERVENTION: TKA. OUTCOME MEASURES: The Medical Outcomes Study Short Form (SF-36) health survey score and the Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index. Univariate analyses were used to compare the case and control groups with respect to baseline variables using the t-test, chi2 test or Fisher's exact test. Functional outcomes were assessed by multivariate analyses. RESULTS: Operative problems were more frequently encountered in the study group, which had longer operative times (p < 0.0001), more difficulties with patellar eversion (p = 0.021) and an increased number of lateral releases performed (p = 0.0089). There were trends toward a significant difference in the pain (p = 0.07), function (p = 0.18) and stiffness (p = 0.14) categories of the WOMAC Osteoarthritis Index between the 2 groups, suggesting poorer functional outcomes of TKA after HTO, but the results did not reach statistical significance. A previous HTO does not affect the general health of patients after TKA, as there was no difference between the 2 groups in SF-36 scores. CONCLUSIONS: TKA after HTO is a technically more challenging procedure than primary TKA. The functional outcomes at a mean follow-up of 5 years after TKA in patients with a previous HTO tended to be inferior but the differences were not significant (p > or = 0.05).