Research shows that injury or trauma to a joint puts it at increased risk of
osteoarthritis later on. The risk may be less when surgery is done to repair the damage. Restoring the normal joint alignment and muscle balance helps the joint function
Problems are more likely to occur when the damage is left unrepaired. Uneven load and force through the joint create changes in the cartilage leading to osteoarthritis.
Long-term results of anterior cruciate ligament (ACL) repair aren't known yet. Studies show that gait patterns don't return to normal for at least a year after ACL repair. Reduced knee flexion can occur with the patellar tendon graft method of ACL repair. Without full knee flexion, normal shock absorption is altered. This could put the joint at risk for early arthritic joint changes.
Right now the emphasis is on rehab after surgery to restore normal motion and strength. Until more is known, retraining the muscles and receptors in the joint is your best bet for a good long-term result.