Your anterior cruciate ligament, or ACL, helps stabilize your knee during physical activities like running. A partial tear or complete rupture of your ACL can lead to knee instability, pain and swelling. Running with a torn ACL may be possible after conservative rehabilitation but depends on the severity of the tear and your symptoms. Consult your physician about your treatment options.
Anterior Cruciate Ligament
Your ACL is located in your knee and connects your thighbone and shinbone. It stabilizes your knee by preventing your shinbone from moving or translating forward during activities like running. A fall, twisting motion or direct hit to your knee can cause damage to your ACL. When you sprain your ACL, you can have a partial tear, or grade-two sprain, or a complete rupture, or grade-three sprain. In severe cases, you may sprain your ACL along with other knee ligaments and tear your meniscus or cartilage.
Immediately following an ACL tear, you may experience pain, swelling, impaired knee function and joint instability. The severity of these symptoms vary based on the damage caused by the injury and your body’s reaction. For example, some individuals may have no knee instability following a partial ACL tear, whereas others may experience knee instability that inhibits normal walking and running. Even without knee instability, running shortly after tearing your ACL is unlikely due to pain and swelling.
The goals of conservative rehabilitation for your torn ACL include managing pain and swelling and regaining normal knee movement, strength and stability. When these goals are met, you may progress back into your normal running routine. On the other hand, you may continue to experience impaired knee function like instability or decreased range of motion even after completing rehabilitation, according to a 2009 Ullevaal University Hospital study. However, wearing a knee brace while running may help eliminate persistent knee instability and pain following rehabilitation.
According to the American Academy of Orthopaedic Surgeons, 90 percent of people with knee instability who do not undergo surgical repair develop meniscus or cartilage damage over time. Secondary injuries like meniscus tears and arthritis may lead to additional pain and swelling, impairing your ability to run long-term. Chronic knee instability and secondary injuries may also lead to muscle loss or atrophy, adhesions or scar tissue build-up and a decrease in your knee's range of motion. Therefore, receiving the appropriate treatment and returning to normal activities only after your knee is healed is imperative to preventing future knee injuries while running.
If symptoms persist after rehabilitation or you run competitively and you have a complete rupture to your ACL, your physician may recommend undergoing surgery before you return to running. After rehabilitation, you may be required to reduce your running pace and distance temporarily. Any alterations or inefficiencies such as a slight limp in your running gait can decrease your athletic performance and increase your risk for future injuries.