The anterior cruciate ligament, or ACL, is one of the major ligaments of the knee that is in the middle of the knee and runs from the femur (thigh bone) to the tibia (shin bone). It prevents the tibia from sliding out in front of the femur. Together with posterior cruciate ligament (PCL) it provides rotational stability to the knee.
How do you injure an ACL?
An ACL injury is a sports related injury that occur when the knee is forcefully twisted or hyperextended. An ACL tear usually occurs with an abrupt directional change with the foot fixed on the ground or when the deceleration force crosses the knee. Changing direction rapidly, stopping suddenly, slowing down while running, landing from a jump incorrectly, and direct contact or collision, such as a football tackle can also cause injury to the ACL. When you injure your ACL, you might hear a "popping" sound and you may feel as though the knee has given out. Within the first two hours after injury, your knee will swell and you may have a buckling sensation in the knee during twisting movements.
How can it be diagnosed?
A relevant history is important for diagnosing ACL injuries and concomitant pathology and should include at a minimum the mechanism of injury, history of hearing/feeling a popping sensation, ability to bear weight, ability to return to play, history of mechanical symptoms of locking or catching, localization of pain if possible, and any history of prior knee injuries.
Diagnosis of an ACL tear is made by knowing your symptoms, medical history, performing a physical examination of the knee, and performing other diagnostic tests such as X-rays and an MRI scan. The MRI can provide confirmation of ACL injury and assist in identifying concomitant knee pathology such as other ligament, meniscal, or articular cartilage injury.
How do you treat an ACL tear?
Treatment options include both non-surgical and surgical methods. If the overall stability of the knee is intact, your doctor may recommend nonsurgical methods. Non-surgical treatment consists of rest, ice, compression, and elevation (RICE protocol); all assist in controlling pain and swelling. Physical therapy may be recommended to improve knee motion and strength. A knee brace may be needed to help immobilize your knee.
The need to proceed with surgery if based on the likelihood of suffering recurrent instability and this is dependent on many factors including age, lifestyle and activity, expectations and the success of non-operative rehabilitation.
Young adults athletes involved in pivoting sports will most likely require surgery to safely return to sports. The goal of surgery is to eliminate or reduce episodes of instability and the incidence of subsequent injuries including meniscal tears.
The usual surgery for an ACL tear is an ACL reconstruction which tightens your knee and restores its stability. Surgery to reconstruct an ACL is done with an arthroscope using small incisions. Your doctor will replace the torn ligament with a hamstring tendon graft. Following ACL reconstruction, a rehabilitation program is started to help you to recover and resume a wider range of activities.
What if I also have a meniscal tear?
Not all meniscal tears are reparable. However if you have a reparable tear or a locked knee due to a displaced tear, it is recommended to repair these menisci when combined with ACL reconstruction because it improves a patient outcome.
When is the best timing to proceed with surgery?
Once you have been assessed, diagnosed and informed of your options, you may decide to proceed with surgery. There is moderate evidence to support reconstruction within five months of injury to help protect the articular cartilage and menisci from further injury due to instability.
Will I need a brace following surgery?
Bracing is usually not necessary, unless a meniscal repair is performed in conjunction with the ACL reconstruction.
Do I need physiotherapy after surgery?
Physiotherapy is essential in recovering and rehabilitating your knee maximally after surgery. The benefit of early accelerated rehabilitation is that patients may be able to return to full, unrestricted activity sooner.
When may I return to sport?
As individuals heal and recover at different rates and each injury has its own unique circumstances, it is difficult to assign a specific endpoint that would favor return to sport. Each patient should be treated individually and functionally advanced to the level of their ability. Premature return to full activity may cause injury to a reconstructed ligament, surrounding structures, or the contralateral knee. Early return in those individuals who elect non-operative management may lead to further injury of surrounding tissues and further decline. After surgery for the non-professional athlete, a period of 9 to 12 months recovering is not unusual.
Can ACL tears be prevented?
Employment of neuromuscular training programmes can reduce non-contact ACL injuries. The PEP Programme (Prevent injury and Enhance Performance) consists of a warm-up, stretching, strengthening, plyometrics, and sport specific agilities to address potential deficits in the strength and coordination of the stabilizing muscles around the knee joint.