Lachman maneuver

Lachman Maneuver is a clinical test used primarily to evaluate for anterior cruciate ligament (ACL) injury in the knee. It was first described by Dr. John Lachman in 1976 and has since become a standard in orthopedic examinations.

Procedure

The Lachman test is performed with the patient lying supine on the examination table. The examiner stabilizes the patient's thigh with one hand, while the other hand grasps the tibia just below the knee. The tibia is then pulled forward to assess the amount of anterior motion of the tibia in comparison to the femur. An intact ACL should prevent excessive forward movement of the tibia. If the tibia moves forward excessively, this is a positive Lachman test and suggests a torn ACL.

Accuracy

The Lachman test is considered to be the most reliable clinical test for detecting an ACL tear. It has a sensitivity of 85-98% and a specificity of 94-100%, making it more accurate than the anterior drawer test and the pivot-shift test, other common tests for ACL injury.

Limitations

While the Lachman test is highly accurate, it does have some limitations. It requires a cooperative patient and may be difficult to perform in patients with severe pain or muscle guarding. Additionally, it may give false positive results in patients with lax ligaments or false negative results in patients with partial ACL tears.

See also

• Anterior cruciate ligament injury
• Knee examination
• Orthopedic surgery