The purpose of this study is identify risk factors for signs and symptoms of osteoarthritis two year post ACL reconstruction from information available at the time of surgery; including patient characteristics (age, gender, body mass index (BMI), activity level, clinical knee alignment), their injuries ("pop" heard at the time of injury, concurrent meniscus, articular cartilage, and collateral ligament injuries), and treatment decisions made during the initial surgery (e.g. meniscus and articular cartilage treatments.)

Primary outcome measures will be the WOMAC pain and stiffness subscales and joint space width measured on weight-bearing radiographs.

Secondary outcome measures will include the knee related quality of life subscale of the Knee Injury and Osteoarthritis Score (KOOS) and Kellgren-Lawrence grading from weight-bearing radiographs.