Common Knee Injuries Part 1 – ACL Injuries

What is it?

ACL is an acronym for anterior cruciate ligament. The ACL is one of 4 main ligaments at the knee. Its primary action is to prevent anterior (forward) shearing of the tibia (lower leg) relative to the femur (thigh bone). It also helps restrict tibial medial rotation (twisting at the knee).

How is it injured?

Most ACL tears are the result of landing or planting the leg in cutting or pivoting sports. ACL tears are usually non-contact injuries.

What is the treatment?

Surgical: the ACL can be surgically reconstructed using an autograft (tissue from ones own body eg. hamstring tendon, patella tendon), an allograft (donated cadaver tissue), or a synthetic graft. These days, hamstring tendon autografts are the most common first choice. It will usually take 9-12months before an athlete can return to sport after reconstruction surgery.

Non-Surgical: ACL injuries can be managed non-surgically with rehab, however the ACL itself will not repair. People that choose this option can live normal lives without a functioning ACL, however their ability to participate in any sports requiring jumping/twisting/pivoting is usually prohibited, as the knee joint will not be stable enough.

Facts about ACL injuries:

1) injury occurs with a four to six fold greater incidence in female athletes compared to males playing the same landing and cutting sports

2) ACL rupture is costly, with estimates of surgery and rehabilitation at $22,000-$32,000 per injury

3) Risk factors include: previous (hip, knee or ankle) injury, ligament dominance, quadriceps dominance, leg preference asymmetries, poor core control

Reference:

Hewett, T. E., Ford, K. R., Hoogenboom, B. J., & Myer, G. D. (2010). UNDERSTANDING AND PREVENTING ACL INJURIES: CURRENT BIOMECHANICAL AND EPIDEMIOLOGIC CONSIDERATIONS - UPDATE 2010. North American Journal of Sports Physical Therapy : NAJSPT, 5(4), 234–251.