Often through traumatic instances, an anterior cruciate ligament injury can occur. This is one of four major ligaments involved in providing stability around and inside the knee joint. The ‘ACL’ as its commonly called, prevents the shin bone moving forward in relation to the thigh bone. When this is ruptured, episodes of giving way may occur. Often, surgical intervention is required, when a hamstring tendon is used to graft the new ACL. The length of rehabilitation required varies, pending specialist protocol and what the patient intends to return to. Quite often a full twelve months is required to return to full sporting capacities in the non professional population. Physiotherapy plays a integral role in assisting the patient back to tasks when appropriate and retraining movement patterns to prevent reinjury.