Fracture of bilok interference screws on insertion during anterior cruciate ligament reconstruction

Abstract New femoral and tibial interference screws for use during anterior cruciate ligament (ACL) reconstruction have been developed using a composite of poly-L-lactic acid (PLLA) and tricalcium phosphate (TCP). The combination is described as having better incorporation than standard bioabsorbable screws with no loss of mass during incorporation and without the brittle nature associated with conventional TCP implants. However, the screw can fracture during insertion, leaving the distal third inside the femoral or tibial tunnel, making extraction and revision difficult. This is a report of 2 cases of PLLA-TCP screw breakage, 1 occurring in the femoral tunnel and 1 occurring in the tibial tunnel.