Greater subchondral vBMD at the tibia is observed between 1 and 5 years of anterior cruciate ligament injury

OBJECTIVES: This study aimed to determine if differences exist in tibial subchondral bone and muscle imbalances between individuals with and without an Anterior Cruciate Ligament (ACL) repair within the past 1 to 5 years (median 3 years). METHODS: Fifteen individuals (ages 18-23 years) that had a unilateral ACL repair with no contralateral knee injuries and 15 age- and sex-matched controls (no prior knee injuries) were recruited to participate. Subchondral bone was measured using peripheral quantitative computed tomography (pQCT) distal to the tibial plateau. Muscle force, power, and force efficiency were measured using single leg jumps performed on a force platform. RESULTS: Within subject analysis showed a greater subchondral vBMD in the injured versus uninjured legs of cases (278±11 mg/cm(3) and 258±6 mg/cm(3), respectively, mean±SD, p=0.01). Subchondral vBMD was greater on the injured leg of cases than controls (267±8 mg/cm(3) and 237±8 mg/cm(3), respectively, marginal mean±SE, p=0.01). No differences were observed between cases and controls for muscle force, power, or force efficiency. CONCLUSIONS: Greater subchondral bone mineral density was observed in participants between 1- and 5-years post-op. Given the results of this study and the known long-term effects of ACL injuries, future research must continue to focus on the prevention of these injuries.