RESULTS OF TIBIAL OSTEOTOMY FOR MEDIAL GO NARTHROSIS WITH 20-YEAR FOLLOW-UP - ONE OSTEOTOMY VERSUS REPEATED OSTEOTOMY

Purpose of the study The study definles the conditions in which valgus osteotomy can produce satisfactory 20-year results in cases of medial unicompartmental gonarthrosis. Material and methods Among a series of 93 osteotomies, 35 knees were followed up for 20 years. Changes to th e medial and lateral femorotibial compartments were identified on forc ed varus and valgus radiographs and on foot standing Xray. The conditi on of the patellofemoral articulation was defined on patellofemoral as pect at 30 degrees flexion. Frontal axial deviation was monitored by p reoperative and postoperative standing film (first year, 10 years and 20 years).Results Only 25 knees still had a satisfactory functional re sult (no mechanical pain). However, among these 25 knees, 13 good func tional results were obtained after a new osteotomy performed between t he 7th and 15th year after initial surgery. There were therefore only 12 knees which managed to reach 20 years with their original tibial os teotomy. Radiologically, in absence of adverse hypercorrection (greate r than 6 degrees valgus), there was no deterioration or only small det erioration of the lateral femorotibial compartment at 20 years even am ong the knees which had undergone two tibial osteotomies. Discussion O steotomy rarely avoids the problem of recurrent deformity which appear s fairly rapidly (before 10 years) when initial correction is poor (be low 3 degrees valgus). However, even correction of between 3 and 6 deg rees valgus was not immune to recurrent varus deformity at long term ( 20 years) : among knees with goniometry between 3 degrees and 6 degree s at the one-year postoperative review, 20 were still within this grou p by the 10th year; but only 9 knees were still in this range at 20 ye ars. Conclusion Whilst longevity of a tibial osteotomy seems limited, a second valgus tibial osteotomy can reproduce the same effects as the first (no pain and preservation of the medial femorotibial compartmen t) 13 repeated tibial osteotomies produced a good result at 20 years f ollow-up which suggests that medial femorotibial gonarthroses in young er patients can be treated conservatively.