Knee
ACL & PCL
Evidence: confirmed
Prone Lachman Test Special Test
Orthopedic Physical Examination & Clinical Assessment Guide
What is it used for?
- Diagnosing ACL Rupture.
- Useful for examiners with small hands or patients with large legs.
How to Perform
- Position: Patient lies prone. The examiner places a hand under the distal thigh (just above the knee) to support it.
- Action: Examiner pushes the tibia anteriorly (downward towards the floor) while stabilizing the femur.
Interpretation of Results
- Positive Test: Excessive anterior displacement or soft end-feel.
Diagnostic Accuracy
- High sensitivity, similar to standard Lachman.
Clinical Context & Limitations
The Prone Lachman Test should be considered as one component of a comprehensive musculoskeletal assessment. No single special test has perfect diagnostic accuracy; thus, clinical decision-making should integrate test results with patient-reported symptoms, mechanism of injury, functional impairment, and relevant imaging.
Clinicians should be aware of potential false-positive results in patients with pain sensitisation, muscle guarding, or poor relaxation. For the Knee region, combining the Prone Lachman Test with complementary examination tests significantly improves overall diagnostic confidence.
References
- Magee, D. J. (2021). Orthopedic Physical Assessment.
