抄録
Correction loss is one of the most important problems after high tibial valgus osteotomy (HTO) for the treatment of osteoarthritic knees, because clinical results are said to relate closely to the femorotibial angle (FTA) . We examined the changes of FTA with at least five-years follow-up in fifty-four knees, and among them 12 bilateral cases were examined for differences of FTA between right knee and left. The average FTA deteriorated year by year, and gained 4 degrees in five years. Using Kaplan-Meier survivor-ship analysis, 87% of patients at 5 years, and 78% of patients at 10 years, did not go beyond 176 degrees of FTA. The average difference of FTA in bilateral cases was around only 2 degrees all through the time. Five out of 24 knees of bilateral HTO showed deterioration of FTA beyond 176 degrees; one case suffered simultaneous deterioration, and her FTA was 183° in her right knee and 182 degrees in her left. Two of the other 3 knees showed between 7 and 10 degrees difference between right and left knees, but those differences were quite similar to those of preoperative FTA. These facts indicate the existence of a tendency to return to the former deformity in osteoarthritic knees, and this cannot be controlled by osteotomy for long periods of time.
