An ACL injury is a stretching or tearing of the anterior cruciate ligament that runs diagonally from the front of the tibia (shin bone) to the back of the femur (thigh bone) and prevents the tibia from sliding forward in relation to the femur as well as provides rotational stability.
Symptoms
- Immediate pain- pain is often lateral or on the outside of the knee
- May feel or hear a “pop” if the ligament tears
- Instability or a feeling of “giving out”
- Swelling and associated stiffness
- Difficulty walking
- Tender joint line
- Loss of range of motion of the knee
Causes
*The majority of ACL injuries are non-contact injuries and the majority involve injury to other structures of the knee as well
- Direct blow to the knee causing excessive angulation of the knee (contact injury)
- A collision (such as a football tackle) as the foot gets stuck in the ground
- Planting and pivoting with a bent knee/changing directions rapidly
- Stopping suddenly such as quick deceleration while running
- Landing incorrectly from a jump
Risk factors
- Sports or activities that require pivoting such as soccer, football, and basketball
- Females statistically are more prone to ACL injury due to genetic gender factors such as pelvic/lower extremity alignment, looseness of ligaments, hormonal influence, as well as less muscular strength and neuromuscular control)
Prevention
- Avoid sports and activities that involve a lot of quick changes of direction.
- Strengthen the muscles surrounding the knee
Diagnosis
- A physician will examine the knee the test the stability in multiple directions. The anterior drawer test and Lachman’s tests are specific for ACL testing as the physician will pull anterior (forward) on the tibia to see if there is excessive looseness in relation to the femur.
- An X-ray will be taken to rule out any bone injury
- An MRI will be ordered to confirm the physician’s suspicion of an ACL injury
Treatment
Non-surgical treatment:
- Non-surgical treatment can be considered with grade 1 and grade 2 ACL sprains as well as in grade 3 sprains (full tears) in individuals that are typically older, have sedentary occupations, and are not involved in recreational activities
- May be prone to chronic instability or secondary injury if a complete tear is not fixed
- Ice, rest, compression, and elevation
- Initially immobilize in a brace for 1-2 weeks and give athlete crutches.
- Physical therapy after initial 2 weeks to restore strength and range of motion to the knee.
Surgical treatment:
- ACL surgical repair –arthroscopic repair where a graft is either taken from another part of the individual’s body (autograft) or from a donor body (allograft)
