Case Manager's Corner

Mechanism of Injury:

Often results from noncontact, low-velocity, deceleration, and rotational injuries to the knee. Valgus, external rotation or hyperextension forces are the most common.

Subjective Symptoms:

Acutely, most patients hear or feel a pop at the time of injury. Patients may develop a hemarthrosis. Subacute and chronic complaints often consist of knee instability. An isolated ACL tear is rarely painful. Pain may be associated with concomitant meniscal tears, collateral ligament tears, bone bruising, or articular cartilage damage.

Objective Signs:

Ligamentous instability measured clinically with Lachman or pivot shift tests. Objectively, laxity is measured with an arthrometer. MRI is often used to confirm the diagnosis and to detect meniscal pathology present in 60-70% of ACL injuries.

Natural History:

Depends upon patient demands and concomitant injury. Higher demand patients (i.e., athletes, laborers) are often unable to compensate and complain of recurrent instability. Repeat episodes of instability may lead to further meniscal damage, articular cartilage injury and possibly arthritis.

Nonsurgical:

Activity modification and physical therapy.

Surgical:

ACL reconstruction using a bone-patellar tendon-bone autograft or allograft, and hamstrings autograft. Preoperative physical therapy to regain extension and quadriceps control, and postoperative physical therapy are usually required.

Nonsurgical:

Approximately 6-8 weeks

Light duty, avoid directional change

Surgical:

Approximately 4-6 months

Light duty, avoid directional change