Anterior Cruciate Ligament

Background

General introduction. Located in the centre of the knee, the anterior cruciate ligament (ACL) is a strong band of tissue that prevents the shin bone (tibia) from extending excessively beyond the thigh bone (femur). The ACL provides almost 90% of the stability to the knee joint and experiences dramatic surcharges during peopleÐ'ÐŽÐ'Їs physical activity. As a result, ACL injuries appear common and usually sports-related traumas. Almost any sport that involves jumping, cutting or twisting has an inherent risk of an ACL rupture. However, in modern medicine these kinds of injuries are especially associated with such events as basketball, football, volleyball, tennis and skiing where the loading on ACL increases in dozens times. Due to the achievements of modern surgery todayÐ'ÐŽÐ'Їs athletes have greater than a 90% chance of returning to their pre-injury level of sports participation.

Anatomy. There are four primary stabilizers of the knee, i.e.: ACL, the PCL (Posterior Cruciate Ligament), the MCL (Medial Collateral Ligament) and the LCL (Lateral Collateral Ligament). These ligaments function in concert with the muscles and cartilage of the knee to help control motion. Proprioceptive (nerve) fibers in these ligaments and the capsule of the knee joint augment this control via reflex feedback. The anterior cruciate ligament and the medial collateral ligament are most often injured in sports.

A knee without an ACL may show signs of instability, with unsettling episodes of unpredictable knee motion during cutting (running with sudden changes of direction), jumping, or running up or down hills. Such episodes put the menisci ("C"-shaped cartilage rings that serve as bumpers between the thigh and leg bones) at risk for injury. Children and adolescents with anterior cruciate deficient knees will typically end up competing at a lower activity level than pre-injury. Also, despite the use of specially designed braces, additional knee injuries during play can occur.

ACL injures occurrence. According to medical statistic, ACL ruptures occur at a rate of 60 per 100.000 people per year in the United States. With society's growing interest in physical activities the scientists expect dramatic growth of ACL related traumas in an early date. As a result, there is a strong necessity to provide an all-round understanding of the ACL injury itself (its anatomy, major reasons of traumas and their prevention, etc.) as well as evaluate the methods that are beneficial in treatment of ACL injuries.

Injuries to the ACL can occur in a number of situations, including sports, and can be quite serious, requiring surgery. An ACL injury may result from a violent, twisting motion (deceleration, valgus, rotation) of the knee, which can occur when an athlete plants his or her foot and suddenly changes direction. The ACL can also tear if the knee is 'hyperextended' (bent backwards).

There are several major identified reasons of ACL injures. They are as following

Ð'Ѓ6Ð'¦1 Sudden stops and twisting motions of the knee, or a force or "blow" to the front of the knee.

Ð'Ѓ6Ð'¦1 The extent of the tear.

Ð'Ѓ6Ð'¦1 Simultaneous injures of the other structures inside the knee joint.

Symptoms of ACL injure. If injured, the ACL usually has the following symptoms:

Ð'Ѓ6Ð'¦1 Pain at the time of impact which dies away afterwards.

Ð'Ѓ6Ð'¦1 Swelling.

Ð'Ѓ6Ð'¦1 If the swelling comes on rapidly then it could be caused by bleeding within the joint.

Ð'Ѓ6Ð'¦1 In the later stages when the swelling has decreased there might be instability in the joint.

Ð'Ѓ6Ð'¦1 Pain when you bend the leg and have the tibia (lower leg bone) pulled forwards.

Classification of ligament injuries. ACL injures are usually graded in terms of their severity:

Ð'Ѓ6Ð'¦1 Grade I sprain Ð'ЁC some micro-tearing or slight stretching occurs, however the overall integrity of the ligament is preserved. The ligament hurts if stressed but is stable.

Ð'Ѓ6Ð'¦1 Grade II sprain Ð'ЁC partial disruption of the ligament. Painful to stress, there is detectable laxity but the ligament has an eventual endpoint.

Ð'Ѓ6Ð'¦1 Grade III tear Ð'ЁC complete ligament tear and laxity with no endpoint or stability to testing. As the nerves in the ligament are torn too, there is often minimal pain with stressing the joint.

Repair and reconstruction of ACL. ACL repair can be accomplished in selected tears where the ligament tissue is in good condition, the tear is close to the bone, and best if the patient is over 35 years old.

Surgical reconstruction of the ACL is indicated for patients with unstable knees who desire to remain active. We reconstruct the ligament with a graft from the patientÐ'ÐŽÐ'Їs own knee or from a donor cadaver knee using a bone-patellar tendon-bone graft. When followed with an intensive rehabilitation program that we custom design for each patient the results are that 90% of patients can return to full sports with a stable knee. ACL reconstruction is a complex process and although the success rate is generally 85-95%, there are times when the reconstruction is unsuccessful.

Rehabilitation. The post-surgery recuperative period and rehabilitation program can be even more important than the surgery itself. Activities should be arranged to promote healing, upgrade flexibility in the knee, and strengthen surrounding muscles. A passive range of motion program (stretching) following surgery aids in the healing process, promotes better nutrient flow to the cartilage caps at the ends of the femur and tibia, and prevents excess tightness from developing in the knee. A hinged knee brace which prevents hyperextension or hyperflexion should be used during the four to six weeks after surgery in order to prevent ruptures of the new ACL (stretching activities take place without the brace on, however).

Research Aims

Generally, amidst all the anatomy, symptoms and reconstruction of the ACL this project will examine major reasons of ACL rupture amidst different groups of patient with the primary focus on sportsmen. The present project is also