A tear in the anterior cruciate ligament is one of the most common knee injuries in both young and old athletes. The ACL helps stabilise the knee joint and when torn creates issues with most sporting activities, causing instability, pain and potentially further damage to the knee. The ACL cannot heal on its own and can’t be repaired without a graft – either from additional tendons from around the knee such as the mid third of the patella tendon a single hamstring tendon or a quadriceps tendon. Occasionally an allograft or a synthetic  graft is used. Organic tendon grafts usually involve nine to twelve months of rehabilitation.