[Results of surgically treated chronic anterior laxities. Apropos of 251 cases reviewed with a minimum follow-up of 3 years].

Two hundred and fifty one chronic anterior laxities operated by intra-articular plasty using a free knee-cap tendon and by the Lemaire extra-articular procedure were reviewed with a minimum 3 year follow-up. Eighty-three per cent of the patients obtained a global functional result excellent or good, eight per cent fair and nine per cent poor. Clinical examination disclosed 24% equivocal pivot shifts and 4% true jerks in internal rotation. Most of the patients, at the check-up clinic, underwent a radiographic and dynamic examination, thereby allowing evaluation of postoperative arthrosis and residual anterior laxity in extension. Frontal radiographs of the knee on unilateral weight-bearing showed 29% joint remodelling, 16% "prearthrosis" and 8% arthrosis. These radiological modifications were most often medial femoro-tibial, they were highly correlated with the patient's age at the time of operation, with the state of the medial meniscus and with the residual laxity in extension. The residual anterior laxity in extension measured on the dynamic radiographs was, on average, 9 mm, i.e. an average difference of 5 mm in relation to the healthy knee; it was highly influenced by the pre- or peroperative treatment of the medial meniscus. Indications of precautions to be taken are defined and suggestions are drawn up whereby residual laxity in extension may be limited.