Progression of osteoarthritis of the knee after unilateral total hip arthroplasty: minimum 10-year follow-up study.

摘要

INTRODUCTION: Patients undergoing total hip arthroplasty (THA) exhibit changes in the alignment of lower extremities following the procedure, and these changes may exert effects on other joints over the long-term. Therefore, we investigated the course of knee osteoarthritis in patients undergoing long-term follow up after THA, in addition to the relationship between the course of knee osteoarthritis and alignment of lower extremities. MATERIALS AND METHODS: We retrospectively performed radiographic evaluation of the course of knee osteoarthritis (OA) after THA. Thirty patients undergoing successful unilateral THA were followed for a minimum of 10 years. RESULTS: Eleven (33%) subjects showed progression of medial tibiofemoral OA on the non-THA side, while only three (10%) showed progression on the THA side, and this difference was significant (P = 0.033). In addition, the mechanical axes on the THA side passed through more lateral regions of the tibial plateau than those on the non-THA side (P = 0.044).CONCLUSION: Medial tibiofemoral OA on the THA side was less likely to deteriorate than on the non-THA side. The reduced vulnerability to OA progression on the THA side may be due to the lower offset and resultant lateral shift in mechanical axes.