INITIAL FIXATION STRENGTH OF POLYLACTIC ACID INTERFERENCE SCREWS IN ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION

The initial fixation properties of bioresorbable polylactic acid (PLA) interference screws designed for anterior cruciate ligament reconstru ction were evaluated using an in vitro bovine model. The surgical tech nique of interference screw fixation of the bone-patellar tendon-bone autograft complex performed clinically was reproduced in an adult bovi ne model. The reconstructed knee was tested oriented in 30 degrees of flexion to allow examination of the femoral and tibial fixation proper ties simultaneously. This model examined the initial fixation strength between PLA and metal interference screws as well as a partially degr aded PLA implant. Data from this in vitro model indicate that PLA inte rference screws can provide similar initial fixation at both time 0 an d after degradation for up to 28 days compared with metal interference screws for bone-tendon-bane ACL reconstructions.