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 one-half of the people who tear their ACL also tear their meniscus in their knee. The diagnosis of an ACL tear usually is made on physical examination but an MRI can be helpful, especially when the patient is too swollen or guarded to allow a thorough examination. The MRI also is needed to diagnose any associated meniscal or cartilage damage.
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.
After a failed ACL surgery, it is most important to determine the cause for the failure so that issue can be addressed, and the ACL reconstruction successfully revised. Revision surgery often is more complex as it has to address other issues such as limited graft options, scar tissue, old hardware, bone loss or infection.
For those patients who do not perform sports that require 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.
For those who perform sports that require frequent pivoting, cutting, jumping and landing, surgery to reconstruct the ACL is usually recommended to allow return to these sports. Surgery also is appropriate for ACL injuries in young active children and in people who have combined injuries to other ligaments, the meniscus, or the articular cartilage. Most patients elect to undergo revision ACL reconstruction to obtain a stable knee, return activities without restriction and protect the remaining cartilage and meniscus from injury.
Initial treatment is focused on returning the knee back to its pre-injury status by reducing the pain and swelling and restoring the range of motion, strength, and gait. Walking with crutches until you walk without a limp is often recommended. Range-of-motion, stretching, and strengthening exercises may be carried out at home, although a referral to a physical therapist or athletic trainer is often recommended. If other ligaments are injured along with the ACL, Dr. Steven Chudik may recommend a brace to help hold the knee stable.