The fate of the poly-L-lactic acid interference screw after anterior cruciate ligament reconstruction

We report the persistence of a poly-L-lactic acid (PLLA) interference screw 2.5 years after anterior cruciate ligament (ACL) reconstruction with Achilles tendon allograft. The arthroscopy was performed because the patient sustained a reinjury of the ACL graft, making ACL revision surgery necessary. At the time of arthroscopy, both PLLA screws were macroscopically still intact but could not be removed in 1 piece. No inflammation could be observed either macroscopically or in the histologic analysis. The biopsy specimen from the femoral insertion of the graft showed parts of the PLLA material surrounded by scar tissue. This case shows that biodegradation of PLLA material in the knee joint, causes no irritation and can take several years, even if the material is in contact with the synovial fluid.