A common knee injury amongst the active population is the damage to or rupture of the anterior cruciate ligament (ACL). The role of this ligament is to stabilize the knee joint by stopping the bottom of the leg from collapsing forward under the knee joint, particularly during deceleration, landing, or turning and cutting actions. It is unusual for the ACL to be injured in isolation; often other ligaments and/or the meniscus are also injured. Those at greater risk of tearing the ACL are, therefore, those involved in jumping and pivoting sports, as well as contact sports, such as soccer and rugby. A muscle strength imbalance between the hamstrings and the quadriceps muscles (back and front of the thigh respectively) can also increase the risk of this injury occurring.
Signs and Symptoms
As the injury occurs, a popping, tearing, or snapping sensation may be heard or felt, followed by swelling around the knee joint. Pain may be felt immediately or occur later and may range from mild to severe. The pain may be felt deep in the knee joint or, more commonly, on the front side of the knee. Generally, one is able to walk on the affected leg; however, this is often associated with a feeling of the knee wanting to collapse or a general feeling of discomfort. Because of the high likelihood of other surrounding tissues being damaged as well, it is important to consult a specialist for further investigation.
Depending on the severity of the damage to the ACL and the involvement of the surrounding structures, an ACL injury is either treated conservatively or surgically.
Conservative management involves rest, ice, compression, elevation and immobilization of the knee joint to reduce swelling. Crutches can be used if walking is too painful. Pain-free range of motion exercises are performed to maintain mobility in the joint. Gentle and appropriate strengthening exercise are done to maintain muscle strength. Physiotherapy is very important in these initial stages of recovery. Upper body exercises can be continued throughout the recovery period. Strengthening, range of motion and proprioception and balance exercises can be progressed appropriately by a biokineticist until the individual is back to full function. This can take anywhere between 6 weeks to 3 months, depending on the severity of the injury and the compliance of the individual with the rehabilitation programme.
If there is a complete rupture of the ACL or multiple surrounding tissues are also affected, surgery is usually recommended so that an individual can return to contact or pivoting-type sports. Depending on the other structures damaged, the repair and recovery will be slightly different. A graft is taken from the hamstring muscle to repair the ACL, which means that the hamstring muscle also needs to be carefully rehabilitated and strengthened to avoid a later hamstring injury. After surgery, the affected leg is immobilized in a full-leg brace, which can be locked at various degrees of flexion and extension. One will more than likely be non-weight-bearing for between 2 and 6 weeks, again depending on damage to other structures, such as the meniscus. Physiotherapy is crucial to maintain range of movement in the joint and reduce swelling. Again, gentle strengthening exercises are done to maintain muscular strength around the knee. Once the brace is removed, the rehabilitation will follow in a similar fashion to the conservative treatment plan, progressing appropriately with the guidance of a biokineticist, with an additional focus on the rehabilitation of the affected hamstring muscle. If properly rehabilitated, one should be able to return to sport if they have not lost the nerve to do so.
Foundations of Athletic Training: Prevention, Assessment and Management