Treatment of Chronic Anterior Knee Instabilities with Combined Intra- and Extra-articular Transfer Augmented with Carbon-PLA Fibers

Abstract

In the treatment of old chronic anterior knee instabilities by anterior cruciate ligament (ACL) insufficiency, isolated reconstruction of the ACL is insufficient because of an associated stretching of the lateral capsule and lateral collateral ligament. A combined intra- and extra-articular transfer (consisting of the central one-third of the patellar tendon, the prepatellar tissue, and the central one-third of the quadriceps tendon) is necessary to repair ACL instability. Augmentation of the autogenous transfer with polylactic acid-coated carbon fibers has several advantages. It improves the transfer's strength by reinforcing its weak zones; gives initial strength during graft remodeling and vascularization, thus avoiding cast immobilization; and allows early active rehabilitation and possibly return to sports activity. The surgical technique is based on biomechanical and biologic principles. The transfer remains attached to the tibial tubercle, passing through a tibial tunnel, through the intercondylar notch, behind the lateral femoral condyle in a bony groove, then on the lateral aspect of the condyle, beneath the lateral collateral ligament, and ending close to Gerdy's tubercle. The preliminary results in 30 patients are encouraging. The subjective and objective results are similar to those previously obtained with nonreinforced methods of repair, except that there is an early return to normal activities.