Torn ACL (cont.)
Benjamin Wedro, MD, FACEP, FAAEM
Dr. Ben Wedro practices emergency medicine at Gundersen Clinic, a regional trauma center in La Crosse, Wisconsin. His background includes undergraduate and medical studies at the University of Alberta, a Family Practice internship at Queen's University in Kingston, Ontario and residency training in Emergency Medicine at the University of Oklahoma Health Sciences Center.
William C. Shiel Jr., MD, FACP, FACR
Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.
In this Article
- Torn anterior cruciate ligament (ACL) facts
- What is the function of the knee joint?
- What is a torn anterior cruciate ligament (ACL)?
- What causes a torn ACL?
- What are symptoms and signs of a torn ACL?
- How is a torn ACL diagnosed?
- What is the treatment for a torn ACL?
- How long does it take to recover from a torn ACL?
- What is the prognosis of a torn ACL?
- Can ACL tears be prevented?
- Find a local Doctor in your town
How is a torn ACL diagnosed?
Televised sporting events have allowed the general public to watch how knee injuries occur, often repeatedly in slow-motion replay.
The diagnosis of an ACL injury begins with the care provider taking a history of how the injury occurred. Often the patient can describe in detail their body and leg position and the sequence of events just before, during, and after the injury as well as the angle of any impact.
Physical examination of the knee usually follows a relatively standard pattern.
- The knee is examined for obvious swelling, bruising, and deformity.
- Areas of tenderness and subtle evidence of knee joint fluid (effusion) are noted.
- Most importantly, with knee injury ligamentous, stability is assessed. Since there are four ligaments at risk for injury, the examiner may try to test each to determine which one(s) is (are) potentially damaged. It is important to remember that a knee ligament injury might be an isolated structure damaged or there may be more than one ligament and other structures in the knee that are hurt.
- In the acute situation, with a painful, swollen joint, the initial examination may be difficult because both the pain and the fluid limit the patient's ability to cooperate and relax the leg. Spasm of the quadriceps and hamstring muscles often can make it difficult to assess ACL stability.
- A variety of maneuvers can be used to test the stability and strength of the ACL. These include the Lachman test, the pivot-shift test, and the anterior drawer test.
- The unaffected knee may be examined to be used as comparison.
It may be difficult to examine some patients when muscle strength or spasm can hide an injured ACL because of the knee stabilization that they can provide.
Plain X-rays of the knee may be done looking for broken bones. Other injuries that may mimic a torn ACL include fractures of the tibial plateau or tibial spines, where the ACL attaches. This second situation is often seen in children with knee injuries, where the ligament fibers are stronger than the bones to which they are attached. In patients with an ACL tear, the X-rays are often normal.
Magnetic resonance imaging (MRI) has become the test of choice to image the knee looking for ligament injury. In addition to defining the injury, it can help the orthopedic surgeon help decide the best treatment options. However, MRI does not replace physical examination and many knee injuries do not require an MRI to confirm the diagnosis.
What is the treatment for a torn ACL?
The major decision in treating a torn ACL is whether the patient would benefit from surgery to repair the injury. The surgeon and the patient need to discuss the level of activity that was present before the injury, what the patient expects to do after the injury has healed, the general health of the patient, and whether the patient is willing to undertake the significant physical therapy and rehabilitation required after an operation.
Nonsurgical treatment may be appropriate for patients who are less active, do not participate in activities that require running, jumping, or pivoting, and who would be interested in physical therapy to return range of motion and strength to match the uninjured leg.
The International Knee Documentation Committee, a collaboration of American and European orthopedic surgeons, developed a questionnaire to standardize the activity level assessment of patients before and after surgery to help guide surgeons and patients to decide whether surgery would be helpful. The activity levels were as follows:
- Level I: jumping, pivoting, and hard cutting
- Level II: heavy manual work or side-to-side sports
- Level III: light manual work and noncutting sports like running and bicycling
- Level IV: sedentary lifestyle without sports
All young athletes should have surgical repair of the ACL because of the potential for lifelong knee instability. A nonsurgical approach might be considered for patients who have level III and level IV lifestyles.
Those patients who are candidates for nonoperative treatment benefit from physical therapy and exercise rehabilitation to return strength to the leg and range of motion to the injured knee. Even then, some patients might benefit from arthroscopic surgery to address associated cartilage damage and to debride or trim arthritic bony changes within the knee. Recovery from this type of arthroscopic surgery is measured in weeks, not months.
The anterior cruciate ligament can be reconstructed by an orthopedic surgeon using arthroscopic surgery. There are a variety of techniques, depending on the type of tear and what other injuries may be associated. The decision as to what surgical option is appropriate is individualized and tailored to a patient's specific situation. Because of its blood supply and other technical factors, the torn ACL ends are not usually sewn together and instead, a graft is used to replace the ACL. Often an autograft, tissue taken from the patient's own body, is a piece of hamstring or patellar tendon that is used to reconstruct the ACL.
Rehabilitation physical therapy and exercise program is often suggested to strengthen the quadriceps and hamstrings before surgery. It may take six to nine months to return to full activity after surgery to reconstruct an ACL injury.
The first three weeks concentrate on gradually increasing knee range of motion in a controlled way. The new ligament needs time to heal and care is taken not to rip the graft. The goal is to have the knee capable of being fully extended and flexing to 90 degrees.
By week six, the knee should have full range of motion and a stationary bicycle or stair-climber can be used to maintain range of motion and begin strengthening exercises of the surrounding muscles.
The next four to six months is used to restore knee function to what it was before the injury. Strength, agility, and the ability to recognize the position of the knee are increased under the guidance of the physical therapist and surgeon. There is a balance between exercising too hard and not doing enough to rehabilitate the knee and the team approach of patient and therapist is useful.
Anti-inflammatory medications, such as ibuprofen (Motrin, Advil), naproxen (Aleve), or ketorolac (Toradol), may be suggested to decrease swelling and pain. Narcotic medications for pain, such as codeine, hydrocodone, or oxycodone (Oxycontin), may be prescribed for a short period of time after the acute injury and shortly after surgery.
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