[High tibial osteotomy for varus deformity of more than 20 degrees]

This study was undertaken to evaluate the results of high tibial osteotomies on varus gonarthrosis, on which a mechanical angular correction of more than 20 degrees was performed.

This retrospective study concerned 46 knees in 38 patients. The average patients age at operation was 60 (min. 51, max. 71). All the patients were evaluated clinically according to the Knee Society Scoring System and radiologically (standing AP, lateral views and monopodal whole leg weight bearing X-Rays) both pre and post operatively. 3 knees have been excluded because of various reasons. The average follow up of the remaining 43 knees was 50.3 months (min. 24, max. 109 months). The preoperative mechanical axis deviation was 22.8 degrees (min. 16, max. 36 degrees).

Postoperatively an optimum valgus alignment was obtained in 31 knees. In 12 knees, the peroperative correction decreased and the mechanical axis was again in varus but with less deformity. According to The Knee Society Scoring System at the last follow-up, the Knee Score was 83, and the Knee Functional Score was 81 (54 and 55 respectively preoperatively). Three cases were reoperated. One internal fixation and bone grafting for nonunion, one reosteotomy for recurrence of the deformity and one total knee replacement for persisting pain were performed. The most frequent complication was the loss of correction which was encountered in 12 knees. Age, follow-up period and alignment were not found to influence significantly the results. Only the arthritis stage, according to Ahlback's radiographic evaluation, was found to be an important factor influencing the results.

Dome shaped osteotomy's results were surprisingly good in these patients. This technique, performed with a cheap fixator, allowed an operatively exact correction of the deformity, an early active mobilization and progressive weight bearing. The dome shaped osteotomy displaces the tibial tuberosity medially and if needed anteriorly, treating effectively the patello-femoral arthrosis which is frequently present in these highly deformed knees.

Chosen because of necessity by the authors, the dome shaped osteotomy stabilized by a Charnley fixator, performed on knees needing an important angular correction, has given surprisingly good mid term results. Furthermore the good results obtained support our belief of not enlarging the arthroplasty indications against those of the osteotomies, even in severe gonarthrosis.