The purpose of this study was to evaluate the different behaviors of the femoral bone in patients after anterior cruciate ligament reconstruction. Twenty-two patients undergoing ACL reconstruction either by double semitendinosus and gracilis tendon graft (DTSG), or ligament advanced reinforcement system (LARS) fixed at the femur with two biodegrad-able pins (RIGID FIX), were evaluated.
In all patients a physical examination was performed and functional outcome scores were obtained at follow up. Instrumental evaluation was performed by multislice CT. The CT scan, which mainly focused on the area of the femoral tunnel, showed an increase in spongy bone out of the socket in the surgery performed with LARS, while in patients treated with DTSG, the bone retained the normal structural characteristics of density of the femoral meta-epiphysis. The CT scan also documented a higher rate of pin biodegra-dation in reconstruction with LARS. The results analysis showed different patterns of re-sponse based on the type of ligament. A bone reaction for mainly mechanical purposes, evidenced by a circumferential fibrous ring, was observed in all patients. Additionally, a bone reaction for biological purposes, characterized by an increase in the spongy tissue associated with a reduction in bone density and a faster reabsorption of pins, was found in patients treated with LARS.
