Long-term evaluation of high tibial osteotomy for medial osteoarthritis of the knee.

Fifty-five medial osteoarthritic knees in 50 patients who had undergone high tibial osteotomies (HTO) were followed up twice: once, six years after surgery, and again, 10-15 years postoperatively. The results were satisfactory in 85% of the knees at the six-year follow-up and in 62% of the knees at the 10-year follow-up. The results post 10 or more years had deteriorated significantly compared to those seen six years postoperatively. In patients maintaining excellent improvement of knee function post 10 or more years, the mean femorotibial angle (FTA) one year after surgery had been 165 degrees; this value remained constant for 10 years postoperatively. The authors believe that an FTA of 164 degrees - 168 degrees should be set as a goal when performing a high tibial osteotomy to ensure favorable long-term results in HTO.