Anterior Cruciate Ligament Injury
ACL injury - one of the most common knee injuries
"With over 200,000 incidents per year in the United States, anterior cruciate ligament (ACL) tears is one of the most common knee injuries, particularly among active teens and young adults."
Anatomy of the ACL
- Grade 1 Sprains: The ligament is mildly damaged. It has been slightly stretched, but is still able to keep the knee joint stable.
- Grade 2 Sprains: The ligament is stretched to the point where it becomes loose. This is referred to as a partial tear of the ligament.
- Grade 3 Sprains: This is a complete tear of the ligament; the ligament has been split into two pieces, and the knee joint is unstable.
Most ACL injuries are complete or near complete tears.
Athletes participating in high demand sports like soccer, gymnastics, football, and basketball are more likely to injure their ACL.
- Loss of full range motion
- Discomfort while walking
- Tenderness along the joint line
- Pain with swelling
Most ligament injuries can be diagnosed through physical examination of the knee. A doctor compares the structures of an injured knee with the non-injured knee.
"Young women are two to eight times more likely than young men to injure the ACL."
Female athletes have a higher incidence of ACL injury than male athletes due to differences in physical conditioning, muscular strength, and neuromuscular control. Other suggested causes include differences in pelvis and lower extremity alignment, increased looseness in ligaments, and the effects of estrogen on ligament properties.
A torn ACL will not heal without surgery. Nonsurgical treatment may be effective for elderly patients with a low activity level. If the knee is overall stable, nonsurgical options might be recommended.
- Bracing - a brace may be worn to protect the knee from instability. Also, crutches may be used to further protect the knee.
- Physical therapy - a rehabilitation program can be started to restore function to the knee and strengthen the leg muscles that support it.
- Rebuilding the ligament - To surgically repair the ACL and restore knee stability, the ligament must be reconstructed. A torn ACL will be replaced with a tissue graft; this graft acts as a scaffolding for a new ligament to grow on. Grafts can be obtained from several sources (the patellar tendon, which runs between the kneecap and the shinbone, hamstring tendons at the back of the thigh, sometimes a quadriceps tendon, which runs from the kneecap into the thigh, or a cadaver graft). The regrowth takes time, and it may be six months or more before an athlete can return to sports after surgery.
- Procedure - Surgery to rebuild the ACL is done with an arthroscope using small incisions. The surgery is less invasive, and its benefits include less pain from surgery, less time spent in the hospital, and a quicker recovery time.