High tibial osteotomy that does not cause recurrence of varus deformity for medial gonarthrosis.

It is widely accepted that high tibial osteotomy (HTO) is an effective surgical treatment for medial gonarthrosis. However, long-term follow-up studies have revealed that the clinical results deteriorate over time and varus deformity often recurs. We performed barrel-vault osteotomy in HTO with a correction angle that did not cause arthritic progression in the medial compartment of the knee or recurrence of varus deformity. Thirty patients (44 knees) were followed clinically and radiographically for a minimum of 10 years (average, 11.4 years). We aimed for an average postoperative femorotibial angle (FTA) of 165.3 degrees (range, 162-169 degrees ) according to our method using a correction angle chosen on the basis of the so-called Mikulicz's mechanical axis. The clinical results were good in 30 (68.2%) knees, fair in 7 (15.9%) and poor in 7 (15.9%). Arthritic progression in the medial compartment was only found in 1 (2.3%) knee, while in the lateral compartment it was found in 17 (38.6%) knees. Of the knees with arthritic progression in the lateral compartment, six (35.3%) were classified as poor. The average postoperative FTAs were 164.3 degrees at 1 year, 164.0 degrees at 5 years and 163.5 degrees at 10 years after the operation, indicating that the knees tended to become slightly valgus over time. The clinical results were not poor after slightly overcorrected osteotomy was performed. Since overcorrection tended to occur, when the preoperative lateral tibial thrust was severe, HTO is not a good indication for such cases.