The application of absorbable interference screws in anterior cruciate ligament reconstruction of the knee joint

Abstract

Anterior cruciate ligament (ACL) injury is a common sports-related condition that can result in knee instability, pain, functional impairment, and subsequent osteoarthritis. ACL reconstruction relies on reliable graft fixation, for which conventional metallic and bioabsorbable interference screws have limitations in biocompatibility, degradation behavior, or mechanical performance. Here, we developed a bioabsorbable interference screw composed of 30% β-tricalcium phosphate (β-TCP) and 70% poly(lactic-co-glycolic acid) (PLGA) for ACL reconstruction. The mechanical properties, in vitro degradation, biocompatibility, and bone–implant integration of the screw were systematically evaluated and compared with those of the commercially available MILAGRO screw in an ovine ACL reconstruction model. The experimental screw exhibited adequate initial mechanical stability, gradual degradation, favorable biocompatibility, and progressive bone ingrowth at the screw–bone interface. Its overall degradation and tissue integration profiles were comparable to those of the commercial control. In addition, a clinical study involving 64 patients demonstrated favorable functional outcomes at 6 months after ACL reconstruction, with no major implant-related adverse events observed. Collectively, these findings support the potential of the β-TCP/PLGA interference screw as a bioabsorbable fixation device for ACL reconstruction, combining mechanical stability with progressive degradation and bone integration.