What is the Lachman Test used for?

Assessing the integrity of the Anterior Cruciate Ligament (ACL), specifically the posterolateral bundle.Considered the “Gold Standard” for acute ACL injury.

How do you perform the Lachman Test?

Position: Patient lies supine. Knee flexed to 20-30°. Action: Stabilize the distal femur with one hand. Grasp the proximal tibia with the other.Force: Apply a quick anterior translation force to the tibia.

What is a positive result for the Lachman Test?

Positive Test: Excessive anterior translation (>3mm) compared to the uninjured side, or a “soft/mushy” end-feel (lack of a sudden stop).

What is the diagnostic accuracy of the Lachman Test?

Sensitivity: 85%Specificity: 94%

Lachman Test – Knee Special Test

What is it used for?

Assessing the integrity of the Anterior Cruciate Ligament (ACL), specifically the posterolateral bundle.
Considered the “Gold Standard” for acute ACL injury.

How to Perform

Position: Patient lies supine. Knee flexed to 20-30°.
Action: Stabilize the distal femur with one hand. Grasp the proximal tibia with the other.
Force: Apply a quick anterior translation force to the tibia.

Interpretation of Results

Positive Test: Excessive anterior translation (>3mm) compared to the uninjured side, or a “soft/mushy” end-feel (lack of a sudden stop).

Diagnostic Accuracy

Sensitivity: 85%
Specificity: 94%

Clinical Context & Limitations

The 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 Lachman Test with complementary examination tests significantly improves overall diagnostic confidence.