The ACL is responsible for controlling both rotation and anterior shifting of the knee during dynamic movement. Most commonly, the ACL tears or ruptures during a weight bearing impact or significant torsion of the upper body whereas the weight of the body acts as a driving force behind the fulcruming effect that tears the tissue. It is quite common in sports that require quick changes in lateral movement like football, basketball, tennis, soccer, and wrestling.
After ACL reconstruction, the patient will be fitted with a brace to stabilize the knee for a short time. Therapy usually starts within a week or two, sometimes even 2-3 days to be sure full ROM is achieved and to minimize muscle loss by starting the retraining process of the quadriceps before more atrophy can occur. The goals of treatment initially are to achieve full extension and retrain the quad to actively contract through full functional ROM. Flexion past 125 degrees is usually avoided for the first stage to prevent compression disruption of the healing bone at the graft ends. Stage two emphasizes full ROM, progressive weight bearing exercise for balance and strength for daily activities. Stage three includes coordination and balance exercise, agility exercise, and full ROM in all planes in all joints of the LE to facilitate return to work, sports, and recreation.