Background: The Lachman and pivot-shift tests are 2 standard manual tests to diagnose anterior cruciate ligament (ACL) insufficiency. However, the global variation of these testing procedures is not known.
Purpose: To survey currently used testing techniques and to measure the knee movement during manual tests among various expert surgeons from across the globe.
Study design: Controlled laboratory study.
Methods: Part 1: descriptive survey. A questionnaire asking about testing procedures of Lachman and pivot-shift tests was conducted among 33 ACL surgeons. Part 2: knee kinematics comparison. Lachman and pivot-shift tests were performed on a unilateral ACL-injured patient by 5 surgeons, while knee kinematics was recorded by an electromagnetic system. Tibial translation was measured during the Lachman test, while tibial translation, rotation, and pivot-shift acceleration were calculated during the pivot-shift test.
Results: Part 1: Tibial anterior drawer by a medially placed hand was widely advocated for the Lachman test. Flexion type of the pivot-shift test maneuver was supported by two thirds, while extension type was supported by one third. However, the "feeling" of subluxation or reduction during the pivot shift was the primary evaluation method used by the vast majority of surgeons. Part 2: Increased tibial translation during the Lachman test was observed in the ACL-injured knee with significant variation between examiners (P < .01). Tibial translation and pivot-shift acceleration during the pivot-shift test increased in the ACL-injured side (P < .01), but tibial rotation was too diverse to find any trend (P = .31). Tibial translation and acceleration of the pivot shift in the ACL-injured knee showed no significant difference between examiners (P > .05).
Conclusion: The Lachman test can display a wide variation of actual movement despite maneuver similarity, while the pivot-shift test could possibly be measurable by tibial translation and/or acceleration beyond their procedural variation.
Clinical relevance: We should recognize the limitations of these manual tests and the possibilities of their objective measurement.