Ten-year magnetic resonance imaging follow-up of bioabsorbable poly-L-lactic acid interference screws after anterior cruciate ligament reconstruction

In a previous study bioabsorbable screws composed of poly-L-lactic acid were used for graft fixation and examined prospectively with serial magnetic resonance imaging (MRI) scans 8, 16, and 24 months after anterior cruciate ligament reconstruction. Autogenous patellar tendon graft was used in all 10 patients. Although the manufacturer's estimated time to absorption was 2 years, only 1 of 20 screws had been absorbed at 24 months' follow-up. After 10 years, 6 patients were available for follow-up. None of the patients had instability, persistent effusions, or clinically detectable adverse reactions to the screws. MRI showed that all of the screws had been absorbed. However, all of the patients who underwent MRI had evidence of intraosseous fluid collections at the tibial BioScrew site (Linvatec, Largo, FL), and 4 of 6 had fluid collections at the femoral screw site. The persistence of intraosseous fluid collections 10 years after implantation underscores the importance of long-term follow-up of bioabsorbable implants, particularly given the rapid evolution of bioabsorbable materials used for interference screws.