HIGH TIBIAL OSTEOTOMY FOR VARUS DEFORMITY SUPERIOR TO 20 DEGREES

Introduction This study was undertaken to evaluate the results of high tibial osteotomies on varus gonarthrosis, on which a mechanical angul ar correction of more than 20 degrees was performed. Material and meth ods This retrospective study concerned 46 knees in 38 patients. The av erage patients age at operation was 60 (min. 51, max. 71). All the pat ients were evaluated clinically according to the Knee Society Scoring System and radiologically (standing AP, lateral views and monopodal wh ole leg weight bearing X-Rays) both pre and post operatively. 3 knees have been excluded because of various reasons. The average follow up o f the remaining 43 knees was 50.3 months (min. 24, max. 109 months). T he preoperative mechanical axis deviation was 22.8 degrees (min. 16, m ax. 36 degrees). Results Postoperatively an optimum valgus alignment w as obtained in 31 knees. In 12 knees, the peroperative correction decr eased and the mechanical axis was again in varus but with less deformi ty. 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 inte rnal fixation and bone grafting for nonunion, one reosteotomy for recu rrence of the deformity and one total knee replacement for persisting pain were performed. The most frequent complication was the loss of co rrection 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, w as found to be an important factor influencing the results. Discussion Dome shaped osteotomy's results were surprisingly goad in these patie nts. This technique, performed with a cheap fixator, allowed an operat ively exact correction of the deformity, an early active mobilization and progressive weight bearing. The dome shaped osteotomy displaces th e tibial tuberosity medially and if needed anteriorly, treating effect ively the patello-femoral arthrosis which is frequently present in the se highly deformed knees. Conclusion Chosen because of necessity by th e 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 obta ined support our belief of not enlarging the arthroplasty indications against those of the osteotomies, even in severe gonarthrosis.