Which special test is most likely to detect an injury of the anterior bundle of the anterior cruciate ligament?

• A. McMurray's test
• B. Anterior drawer test
• C. Lachman's test
• D. Pivot shift test

Answer: (B)

The anterior drawer test is specifically designed to assess the integrity of the anterior cruciate ligament (ACL) by evaluating the amount of anterior translation of the tibia relative to the femur. When the ACL is intact, the tibia should not move excessively forward. In the case of an injury to the anterior bundle of the ACL, there will be increased anterior translation when the test is performed, indicating a compromised ligament.

This test is particularly focused on assessing the whole ACL, and the anterior bundle is the part of the ligament that is primarily responsible for resisting anterior tibial translation. Thus, an injury or tear in this section would be most effectively detected through this specific testing mechanism.

Other tests like the Lachman's test also assess the ACL's integrity but may involve different angles of force application or stress on the knee; however, the anterior drawer test is more directly focused on the anterior translation aspect. In contrast, tests like McMurray's and the pivot shift test are more specialized for evaluating the meniscus and functional instability, respectively, rather than directly assessing the anterior bundle of the ACL.