One of the most common knee injuries is an anterior cruciate ligament sprain or tear (“ACL tear”). The ACL is a ligament that connects the femur (thighbone) to the tibia (shinbone) at the knee and provides stability when rotating the knee. Most ACL tears occur as an injury where the knee falls inward when rotating, and they are especially common in certain sports such as soccer, football, basketball, skiing, and tennis. ACL reconstruction surgery can stabilize the knee and prevent irreversible damage while allowing you to return to all (or at least most) normal physical activities.
In most cases, an ACL tear or sprain is the result of a direct injury. Symptoms will usually present immediately or shortly after the injury occurs. Symptoms can include:
- A “popping” feeling or sound in the knee area at the instant of the injury
- Knee instability or buckling feeling that the knee will give way
- Knee pain
- Knee swelling
- Knee stiffness
- Decreased range of knee motion
ACL injuries can cause recurrent instability, which may irreversibly damage the cartilage and meniscus of the knee. Treatment with ACL reconstruction surgery will usually be necessary to stabilize the knee, prevent further damage, and make it possible for the patient to return to sports and other physical activities that require full knee rotation and pivoting movements.
- Physical Therapy: PT is usually recommended to regain some knee motion and strength before surgery for an ACL tear. Called “prehab”, this helps with range of motion and recovery after ACL surgery.
- Anti-Inflammatory Medication: Non-steroidal anti-inflammatory medications can decrease inflammation and pain due to an ACL tear. Patients undergoing physical therapy may benefit from taking anti-inflammatory medications (over-the-counter or prescription strength) to reduce pain while they work to regain strength and mobility.
- Knee Bracing: A knee brace is often worn after an ACL tear to prevent instability events that could further damage the knee structures. The brace should be worn during the time before the surgery and during recovery after surgery. As a recovery tool after surgery, the knee brace provides stability and supports the knee as it heals and regains strength.
- ACL Reconstruction Surgery: For most patients, especially those who want to resume an active lifestyle, ACL reconstruction surgery is necessary to restore a sprained or torn ACL. By transferring tendons or ligaments from another part of the knee, this surgery can restore stability to the knee. This arthroscopic procedure typically takes under 2 hours, and patients can usually go home the same day.
Frequently Asked Questions
ACL reconstruction surgery is a minimally invasive procedure that begins with two small incisions around the knee joint. Through these incisions, a small camera may be inserted to allow visualization, and tools may be inserted to provide repairs. Grafts (usually a part of the patellar tendon attached to bone on each end) will be taken from another part of the knee to restore ACL functionality. Bone tunnels will be made in the femur and tibia to make room for the graft, and metal screws will be used to secure the graft and allow for bone-to-bone healing. Usually, the procedure is performed under general anesthesia with a nerve block, and dressings and a knee brace will be placed before the patient wakes up after the surgery. Patients can usually return home the same day to begin their recovery.
A knee brace is a necessary part of recovery from ACL surgery and helps the tissues remain stable as they mend and strengthen. When patients have regained enough strength to do a straight leg raise while lying down (keeping the knee completely straight while lifting the leg), the brace is usually discontinued. Until this point, the knee brace should be worn and locked in full extension when walking, and it should only be unlocked and removed according to postoperative instructions (usually three times per day and for hygiene purposes).
An ACL tear usually occurs from a non-impact injury, such as pivoting the leg. It is usually accompanied by severe pain, swelling, and a feeling of instability. The symptoms themselves are a strong indicator that the ACL has been damaged, and a diagnosis can be confirmed with a detailed history and exam, including x-rays and MRIs. These additional tests also determine whether there are any accompanying fractures and whether any other parts of the knee have also been damaged.
The vast majority of patients with an ACL tear are recommended for surgery. Patients who are generally sedentary or who are older with arthritis may choose nonoperative treatments; however, surgery is strongly recommended for younger and more active patients because the recurrent instability from an ACL tear can lead to irreversible damage that may further inhibit mobility.
For those with an ACL sprain or tear, ACL reconstruction surgery restabilizes the knee and reduces the chance of recurrent instability events that could cause irreversible damage. This surgery also makes it possible for patients to return to all (or at least most) normal physical activities. It is important to understand that patients who have had an ACL tear have a higher likelihood of developing arthritis, even after a successful ACL reconstruction surgery. This makes it even more important to restore the knee as best as possible after an ACL injury to maintain long-term mobility.
The most common risk of postponing or avoiding surgery for an ACL tear is recurrent instability, in which the knee buckles because it cannot rotate, pivot, or properly support the body. This can cause irreversible damage to the knee cartilage and meniscus tears. Another risk is that an ACL tear may prevent you from being able to return to sports and physical activity. Because these risks can severely impact your quality of life, it is recommended that you carefully consider surgery for treating your torn ACL.