The clinical outcomes and the ability to sit straight in the Japanese style following high tibial osteotomy combined with osteochondral autologous transfer for osteonecrosis of the medial femoral condyle.

BACKGROUND: There have been some reports of high tibial osteotomy combined with osteochondral autograft transfer for osteonecrosis of the medial femoral condyle of the knee. However, few of them have focused on the deep knee flexion needed to sit straight in the Japanese style. PURPOSE: To evaluate the clinical outcomes and the knee flexion of HTO combined with OAT for osteonecrosis of the medial femoral condyle of the knee, especially the ability to sit straight in the Japanese style. METHODS: Between 1998 and 2012, valgus HTO combined with OAT was performed in 23 patients for stage IV osteonecrosis according to Koshino's radiological classification of the medial femoral condyle. The follow-up period was more than 2 years in all cases. The mean age at the time of the surgery was 65.8 years, and the mean follow-up period was 72.2 months. The function of the knee and the ability to sitting straight in the Japanese style were examined. Twenty-one knees were examined with second-look arthroscopy to assess the recipient and donor sites. RESULTS: The JOA scale and IKDC subjective scores were significantly improved. Twelve patients were able to sit straight in the Japanese style after the surgery, compared to 3 patients who were able to do so before surgery. On second-look arthroscopy of 21 knees, the average ICRS score was 10.5 points. No patient needed additional surgery except for removal of the implants. CONCLUSION: Valgus HTO combined with OAT is one treatment option for osteonecrosis of the medial femoral condyle with osteoarthritis. In the present study, many of the patients regained good knee function, and 50% of the patients were able to sit straight in the Japanese style after surgery, which is a higher rate than after total knee arthroplasty and unilateral knee arthroplasty.