Medical imaging
Though clinical examination in experienced hands can be accurate, the diagnosis is usually confirmed by magnetic resonance imaging, which provides images of the soft tissues like ligaments and cartilage around the knee. It may also permit visualization of other structures which may have been coincidentally involved, such as the menisci or collateral ligaments. An x-ray may be performed in addition to evaluate whether one of the bones in the knee joint was broken during the injury.MRI is perhaps the most used technique for diagnosing the state of the ACL, but it is not always the most reliable technique as the ACL can be obscured by blood that fills the joint after an injury. Arthrometers/Laximeters
Another form of evaluation that may be used in case physical examination and MRI are inconclusive is laximetry testing (i.e. arthrometry and stress imaging), which involve applying a force to the leg and quantifying the resulting displacement of the knee. These medical devices basically replicate manual tests but offer objective assessments. The GNRB arthrometer, for example, is a knee arthrometer that is considered more effective than the Lachman test. Classification
An injury to a ligament is called a sprain. The American Academy of Orthopedic Surgeons defines ACL injury in terms of severity and classifies them as Grade 1, 2, or 3 sprains. Grade 1 sprains occur when the ligament is stretched slightly but the stability of the knee joint is not affected.
Asymmetry in the repaired knee is a possibility and has been found to have a large effect between limbs for peak vertical ground reaction force, peak knee-extension moment, and loading rate during double-limb landings, as well as mean knee-extension moment and knee energy absorption during both double- and single-limb landings. Analysis of joint symmetry along with movement patterns should be a part of return to sports criteria. Rehabilitation
The goals of rehabilitation following an ACL injury are to regain knee strength and motion. If an individual with an ACL injury undergoes surgery, the rehabilitation process will first focus on slowly increasing the range of motion of the joint, then on strengthening the surrounding muscles to protect the new ligament and stabilize the knee. Finally, functional training specific to the activities required for certain sports is begun. It may take six or more months before an athlete can return to sport after surgery, as it is vital to regain a sense of balance and control over the knee in order to prevent a second injury. Prognosis
The prognosis of ACL injury is generally good, with many people regaining function of the injured leg within months. ACL injury used to be a career-ending injury for competitive athletes; however, in recent years ACL reconstruction surgery followed by physical therapy has allowed many athletes to return to their pre-injury level of performance.Long term complications of ACL injury include early onset arthritis of the knee and/or re-tearing the ligament.