More severe injuries with instability of the knee may require surgical repair or reconstruction. Repair may be performed for injuries within a few weeks if the tear of the ligament is from the upper or lower attachment. If the ligament is torn in the middle or the injury is older than three weeks, then a reconstruction is performed to stabilize the knee. The reconstruction can be performed using a tendon graft (either from the patient or a cadaver tendon) through bone tunnels.




