ACL Pain, Diagnosis, and Treatment - Should I See and Orthopedic Surgeon?

The Anterior Cruciate Ligament or ACL, lies deep within the knee joint, connecting the thigh bone with the shin bone. Its function is to prevent excessive forward movement of the shin in relation to the thigh and also to prevent excessive rotation at the knee joint.

The ACL can be injured in several different ways, most notably by landing from a jump onto a bent knee then twisting, or landing on a knee that is over-extended. In collision sports, direct contact of the knee from opponents can cause damage to the ACL. Because of the amount of force that is required to damage the ACL it is not uncommon for other structures within the knee such as the meniscus or medial ligament to also be damaged and could require a professional diagnosis.

A moderate impact against the inner side of the knee joint causes the Lateral Collateral Ligament to rupture. A more violent impact causes the Anterior Cruciate Ligament to also rupture. In severe cases the Posterior Cruciate Ligament ruptures.

ACL injuries have been reported to occur more often now than ever before, which may be due to the increased intensity of sporting activity. In soccer, it is reported that for every 1000 hours of soccer played (training and matches) there are between 4 and 7 ACL injuries. Many high profile professional players have suffered this injury including Paul Gascoigne, Alan Shearer, Gustavo Poyet, Roy Keane and Ruud Van Nistelroy.

Signs & Symptoms
At the moment of injury the person may experience a snapping sensation deep within the knee. There will be pain, proportional to the force and degree of damage to other structures within the knee joint. In some cases the person may feel able to continue playing, but as soon as the ligament is put under strain during sports activity, the knee joint will become unstable. A classic example of this was Paul Gascoigne during the 1991 FA Cup Final, who attempted to continue playing before being stretchered off.

The reason the person is unable to carry on is that the restraining function of the ACL is absent and there is excessive rotation and forward movement of the shin in relation to the thigh. After a couple of hours the knee joint will become painfully swollen due to what is called a haemarthrosis - bleeding within the joint. This swelling provides a protective function by not allowing the person to use their knee.

Treatment
During the acute stage of the injury (the first 48-72 hours) exact diagnosis is very difficult due to the gross swelling around the joint. Once the initial treatment to decrease the swelling has taken affect the clinical diagnosis may be possible. This may be achieved by the medical personnel performing stress tests on the knee ligaments - the degree of laxity within the joint will allow the clinician to estimate the degree of damage. If there is any doubt, or to confirm the clinical tests, the patient is sent for further investigations. Most commonly an MRI scan is used to ascertain the level of knee injury. In some cases the MRI scan may not give a clear picture of the damage and it may be necessary to survey the joint with an arthroscope. The combination of these findings allows the orthopaedic consultant to build a picture of the extent of the damage.

The treatment of the ACL injury is dependent upon the amount of damage and the subsequent functional impairment, the age of the patient and the level of sporting activity. If the diagnostic investigations reveal only a partial tear of some of the fibres of the ACL, and there is minimal instability, then a conservative approach with a physiotherapist is usually indicated. This option is also more likely for adolescents and more sedentary individuals. In the case of individuals who are involved in a high level of sport where a degree of instability is functionally unacceptable, surgical reconstruction of the ligament is the surest way to restore normal function.

Surgery to reconstruct the ACL has evolved beyond recognition since the first ACL repair in 1963. By 1980, Cambridge surgeon David Dandy had begun using an arthroscopic technique. Development has continued since then and the latest surgical technique is an arthroscopic procedure where a strip of the patella tendon from the patient's knee is removed and used as a graft to replace the ACL.

In addition to advances in the surgical procedure, there have been advances in post-operative rehabilitation that have seen a return to full activity in most cases in less than six months.