Cruciate Ligaments of the Knee

Anterior Cruciate Ligament

The anterior cruciate ligament (ACL) in the knee prevents the tibia from sliding upon the femur by acting like a tether or rein. Injury to the ACL usually results from a twisting injury. Swelling, pain and instability in the knee generally point to an ACL tear. A physician will assess the knee for the severity of the sprain. X-rays are taken to rule out small associated fractures, and sometimes an MRI (magnetic resonance imaging) is necessary to confirm ligamentous tears and evaluate possible meniscal injury as well.

Treatment of partial ligament tears include a brief period of rest (24-72 hours), the use of anti-inflammatory medication, compression bandages, elevation and ice in an effort to reduce swelling. A gradual program of quadriceps and hamstring strengthening is emphasized as well. A dedicated physical rehabilitation program can be helpful for a return to full activity. Patients with complete tears are evaluated for potential recovery after nonsurgical treatment. Consideration is given to age, weight, activity level and severity of the injury.

If surgery is selected by both the physician and the patient, a ligament is reconstructed usually from the patient's own bone and tendon. Surgical intervention is generally quite successful if undertaken in conjunction with a dedicated physical therapy program. The reconstructed ligament itself takes up to a year to fully heal, but a patient can gradually return to weight bearing and athletic activity as he or she progresses through the rehabilitation program.

Posterior Cruciate Ligament

The posterior cruciate ligament also extends from the tibia to the femur, but in the back of the leg. It prevents the tibia from sliding backwards. Sprains of this area tend to occur in tandem with other major injuries to the knee. Posterior cruciate ligament (PCL) tears can be managed conservatively with a program of physical therapy emphasizing the hamstring and quadriceps muscle groups. With this injury, patients report a vague feeling of instability and this injury is generally confirmed with an MRI (magnetic resonance image).

If surgical management of this injury becomes an option, a lengthy and dedicated period of physical rehabilitation ensues, especially when other knee injuries are involved. Most patients respond well to treatment, however, and can return to an active life.