A positive Lachman test indicates ACL pathology?

• A. Rule In
• B. Rule Out
• C. Both
• D. Neither

Answer: (A)

A positive Lachman test means the ACL is not functioning properly, so it strongly supports that ACL pathology is present. This test specifically looks at anterior translation of the tibia relative to the femur with the knee flexed about 20–30 degrees; if there’s excessive forward movement or a soft/measured end feel, it indicates ACL disruption.

In diagnostic reasoning, a positive result is used to rule in the condition because this test is highly specific for ACL injury. A negative result would be more useful for ruling out the injury, but since the result here is positive, the finding best represents confirming ACL pathology. The other options don’t fit: a positive result doesn’t indicate ruling out, nor does it indicate both or neither.