An anterior cruciate ligament (ACL) sprain is a tear of one of the four major ligaments of the knee. The ACL is a ropelike structure in the center of the knee that helps maintain the normal relationship of the femur (thigh bone) and the tibia (leg bone). When torn, the ACL does not heal and the knee can be unstable (shifts or gives way) during sports that require pivoting, changing direction (cutting), jumping, or landing. About half the people who tear their ACL also tear their meniscus in their knee.
For those who want to return to sports that require pivoting, cutting, and jumping and landing, revision surgery is usually required. Surgery also is recommended for ACL injuries combined with other ligament, meniscus, or cartilage injuries. Outcomes for revision ACL surgery depend on the ability to address the cause of the failure, i.e., technical problems with the first surgery, infection, incomplete rehabilitation, poor pivoting, cutting, landing mechanics, etc.
For those patients who do not perform sports requiring frequent pivoting, cutting, jumping and landing, surgery is not required and rehabilitation is recommended. Individuals usually can continue to jog, cycle, lift weights and swim without ACL surgery; however, they are at a greater risk for progressive damage to their meniscus and cartilage from abnormal knee mechanics. Rehabilitation of ACL tears usually concentrates on reducing knee swelling, regaining knee range of motion, regaining muscle control and strength, functional training and education to avoid sports/ activities that require pivoting, cutting, changing direction, jumping and landing.
Following ACL reconstruction, the graft may fail due to technical errors from the initial surgery, incomplete rehabilitation, returning to sport too soon following reconstruction, graft biologic failure or rejection, failure to retrain good cutting, pivoting, landing mechanics and movement patterns and re-injury. Knowing what caused the failure is most important so that issue can be addressed and the ACL reconstruction successfully revised. Revision surgery often is more complex because it must address other issues such as limited graft options, scar tissue, old hardware, bone loss or infection.