Written and Peer Reviewed by OCC Physicians
About ACL Tears
Typically, patients experience acute pain and subsequent swelling to their knee following an ACL tear. During the injury, patients can often feel a pop. The knee will often feel unstable and can sometimes give way after the injury. There can be a loss of motion due to the swelling as well. Patients may have other symptoms if there are additional injuries such as meniscus tear or other ligament injuries. In an isolated ACL tear, the initial pain may resolve, and patients can experience continued instability.
Cause and Anatomy of an ACL Tear
The ACL is one of two cruciate ligaments of the knee (the other is the posterior cruciate ligament). The ligament spans the knee joint and functions to add stability to the knee. Without it, the knee is unstable, especially with cutting, pivoting, and shifting movements. An ACL tear usually occurs due to twisting of the knee. Injuries are common in athletics but can happen with falls and other injuries. Female athletes are at higher risk for ACL tears. Common sports for ACL tears are soccer, basketball, football, and skiing.
Diagnosis of an ACL Tear
Early diagnosis can be made at the time of injury before the knee becomes too swollen and painful. The examiner typically performs a Lachman test and checks for a pivot shift of the knee. Typically, by the time a patient sees an orthopedic surgeon, the knee has become more swollen and painful making the exam more difficult to interpret. Initially, an X-ray will be obtained to look for fractures or avulsions as the mechanism of injury can cause a fracture. Ligaments won’t be seen on an X-ray; therefore, your doctor will order an MRI to further evaluate the injury. This will also evaluate for other injuries such as a meniscus tear or other ligament damage.
What Are My Options?
Non-surgical treatment of ACL tears is not common, especially in younger patients. For patients who are older, less active, have osteoarthritis, or are poor surgical candidates, a trial of non-operative management can be attempted with RICE (rest, ice, compression, and elevation) therapy followed by physical therapy. A brace may also be suggested if there are feelings of instability.
The ACL does not heal itself therefore when patients wish to return to higher-level activities, ACL reconstruction will be recommended. A graft from the patient or a cadaver will be used to “create” a new ACL for the patient. In younger patients, typically the surgeon will recommend an autograft (tissue from the patient) to avoid a higher risk of retear. In older athletes, an allograft (tissue from a cadaver) may be recommended as retear rates are not as high. There are several autograft options including patellar tendon, hamstrings tendon, and quadriceps tendon. Each has its pros and cons and should be discussed with your surgeon.
The surgery is usually an outpatient surgery where you go home the same day. The surgery may be delayed until the patient has minimal swelling and near full range of motion. Sometimes the doctor will recommend physical therapy even before the surgery to work on swelling and motion. The surgery uses arthroscopy for a majority of the case to visualize the knee joint. There will be a few extra incisions to position the new ACL into the knee.
After surgery, rehabilitation protocols can vary by surgeon, but most allow weight-bearing and early physical therapy. Crutches will be used initially until the patient can weight bear effectively. Early goals are to reduce swelling and work on motion. Exercises will be started to engage your quadriceps muscle which is usually weak after surgery. Strengthening will be pivotal to a successful outcome.
Common risks of surgery include swelling after the surgery. This will cause stiffness early on. That’s why it is paramount to work on elevating and icing following surgery. The risk of retear can range from 1-25%. There are a multitude of risk factors for retear including age, activity level, allograft in young patients, etc. Talk to your doctor about certain risk factors. There is a small chance the knee is stiff long-term. If you are having difficulty getting back to the full range of motion, your surgeon may recommend a procedure to help break up scar tissue.
Return to sporting activities is typically between six to twelve months post-op depending on how the patient rehabilitates. This varies from patient to patient and should be determined on a case-by-case basis. Some surgeons will recommend a sports-specific ACL brace when returning to sport.
Frequently Asked Questions
What graft is best for me?
This is best addressed by the surgeon on a case-by-case basis.
I tore my ACL. Will I ever be able to get back to sports?
Yes, the majority of patients return to their sport following ACL reconstruction. It is imperative to rehabilitate appropriately for the best chance to get back to sports.