What Is an ACL Tear?
The anterior cruciate ligament (ACL) is one of the main stabilizing ligaments in the knee. It connects the thigh bone to the leg bone and controls abnormal motion during cutting, turning, and pivoting actions required during athletic activity.
Causes
ACL injury typically occurs during athletics, where jumping, pivoting, and rapid change of direction occur. Football, basketball, lacrosse, soccer, and skiing are some sports known to have high ACL injury rates. Contrary to popular belief, the ACL can tear without contact. In this case, the ligament, which is made of dense fibrous tissue, fails with a twisting mechanism. This non-contact injury occurs more commonly in female athletes.
Symptoms
Typical symptoms include:
- Pain
- Immediate difficulty with walking
- Sensation of knee instability
- Immediate swelling
- Popping sound at the time of injury
Treatment
The treatment of ACL tears is highly individualized. After the ACL tears, there is a very poor blood supply, and the ability of the ligament to heal is limited. A well-trained orthopedic sports medicine physician can make an accurate diagnosis by doing an exam that tests the competency of this ligament. The physician usually obtains X-rays to check for small fractures, but an MRI is also often obtained. The MRI will confirm the tear of the ACL but, more importantly, will check for the presence of other soft tissue injuries to the knee known to occur with an ACL tear.
Some patients will require surgery, while others can be treated with non-surgical methods, including bracing and knee rehabilitation. The decision for treatment should be a discussion between you and your surgeon, examining all the injuries that have occurred, the demands of the patient, and athletic and work requirements. Generally, patients who wish to remain highly athletic, have torn cartilage, or are unwilling to change their active lifestyle will be candidates for surgery.
Considering that the ACL has limited ability to heal, simply sewing the torn ends will not be successful. Modern ACL surgery requires using another tendon called a “graft” to substitute for the torn ACL. These grafts are inserted into the knee with an arthroscope, which is a very small lens placed into the knee joint and connected to a camera and monitor so the surgeon can examine and operate on the knee with less invasive techniques.
When patients choose non-operative treatment, the most common complication is recurrent knee instability. This means that the knee is unreliable, may give out with turning sports, and has a small risk of causing increasing damage to the joint surface and cartilage.
Rehabilitation after surgery will focus on restoring the range of motion, protecting the surgery, and minimizing muscle atrophy. Typically, a brace and protected weight-bearing crutches are utilized for several weeks. You will then progress to strengthening exercises and more sport-specific training. Most patients are allowed to return to sports between 7 to 9 months. However, the use of a brace when returning to sports is individualized. There is no scientific evidence that braces prevent ACL injury.