Anterior Cruciate Ligament Injuries – Causes, Symptoms and Treatment

The anterior cruciate ligament (or ACL) is one of the four major ligaments of the knee. It connects from a posterio-lateral part of the femur to an anterio-medial part of the tibia. These attachments allow it to resist anterior translation of the tibia, in relation to the femur. More specifically, it is attached to the depression in front of the intercondyloid eminence of the tibia, being blended with the anterior extremity of the lateral meniscus.

Causes Of ACL Injuries

Anterior cruciate ligament (ACL) injuries are caused when the knee is straightened beyond its normal limits (hyperextended), twisted, or bent side to side.

The chance of injury is higher if more than one of these movements occurs at the same time. Contact (being hit by another person or object) also can cause an ACL injury.

A sprain on the outside of the knee, the lateral collateral ligament, is caused by a blow to the inside of the knee, which forces the knee to the outside. This is much less common than an MCL sprain because it is hard to get hit on the inside of the knee. Usually, your leg gets in the way and takes the blow.

Hyperextension of the knee, that is, if the knee is straightened more than 10 degrees beyond its normal fully straightened position, is a very common cause of an ACL tear. This position of the knee forces the lower leg excessively forward in relation to the upper leg

Symptoms of ACL Injuries

Symptoms of a severe and sudden (acute) anterior cruciate ligament (ACL) injury include:

Feeling or hearing a "pop" in the knee at the time of injury.

Sudden instability in the knee (the knee feels wobbly, buckles or gives out) after a jump or change in direction or after a direct blow to the side of the knee.

Treatment of ACL Injuries

The ACL is located inside the knee joint and stabilizes the joint by preventing the shinbone (tibia) from sliding forward beneath the thighbone (femur). A hard twist or excessive pressure on the ACL can tear it, so that the knee gives out and can no longer support the body. Unless an injured ACL is accurately diagnosed and treated, the cushioning cartilage (the menisci) in the knee could be seriously damaged. Without this cushion, the thighbone and the shinbone would rub against each other, leading to further damage.

Others opt for surgical reconstruction. Whether surgery is right for you depends on many factors, including:

When swelling in your knee has gone down and you are able to stand with equal weight on both legs, you may do the remaining exercises.

Sit on a firm surface with your legs straight in front of you. Slowly slide the heel of your injured leg toward your buttock by pulling your knee to your chest as you slide. Return to the starting position. Do 3 sets of 10.

Use crutches if it hurts to put weight on your knee, until you can see your health professional. Crutches can be rented from most pharmacies. When you call for an appointment, tell your health professional that you are using crutches. Crutches should not be used for long because a lack of activity can cause muscle tissue to waste away and result in restricted movement of the knee.