Knee Orthopaedic Test: Lachman Test

The Lachman Test assesses anterior tibial translation with the knee in slight flexion and is commonly used when ACL injury is suspected. A positive test may include increased anterior translation or a soft end-feel compared with the other side. Recent systematic reviews suggest the Lachman Test remains useful but earlier diagnostic accuracy estimates may have been overestimated, so it should be interpreted with the mechanism, swelling, pivot shift, anterior drawer, lever sign and functional findings.

Introduction

A client may report a pivoting knee injury, a pop, rapid swelling, giving way or difficulty trusting the knee during change-of-direction tasks. The Lachman Test is commonly used to assess anterior tibial translation and possible ACL involvement.

Recent systematic reviews on ACL physical examination tests show that Lachman, anterior drawer, pivot shift and lever sign tests all have diagnostic value, but performance depends on timing after injury, guarding, partial versus complete rupture and study methods.  

Quick Summary

Test name: Lachman Test
Purpose: Assess anterior tibial translation and possible ACL involvement
Body region: Knee
Commonly associated presentation: ACL injury, anterior knee instability, giving way after pivoting injury
Positive finding: Increased anterior tibial translation, soft or absent end-feel, apprehension or familiar instability compared with the opposite side
Negative finding: No meaningful side-to-side difference and firm end-feel
Best used with: Anterior Drawer Test, Pivot Shift Test, Lever Sign Test, swelling assessment, mechanism of injury and functional testing
Key limitation: Pain, swelling, guarding and examiner technique can affect accuracy

What Is the Lachman Test?

The Lachman Test is an orthopaedic knee test used to assess anterior translation of the tibia relative to the femur with the knee in slight flexion, commonly around 20–30 degrees.

It is strongly associated with ACL assessment because this position reduces the influence of some secondary stabilisers compared with testing at deeper knee flexion.

Why It Is Used

The test is used when ACL injury is suspected based on mechanism, swelling, instability, giving way or pivoting trauma. It can help guide further assessment, referral and programming decisions.

What It Assesses

The Lachman Test assesses anterior tibial translation and end-feel.

It does not directly visualise the ACL, identify tear type, determine surgical need, rule out meniscal injury or assess all rotational instability on its own.

Who It Is Useful For

This test may be useful for clients with suspected ACL injury, acute or subacute knee trauma, giving-way episodes, pivoting injury history or anterior instability concerns.

It may not be suitable when pain, swelling or guarding prevents relaxation, or when the client cannot tolerate the testing position.

When to Use This Test

Use the test when ACL injury is suspected and the knee can be positioned safely in slight flexion.

When Not to Use or When to Be Cautious

Use caution with suspected fracture, high swelling, severe pain, locked knee, marked guarding, neurovascular symptoms or suspected multi-ligament injury requiring urgent referral.

Equipment Required

Treatment table
Pain scale
Measurz for recording
Optional comparison side notes
Optional referral notes
Optional arthrometer if available

Step-by-Step Protocol / Practice

Setup

Position the client supine with the tested knee slightly flexed.

Client position

The client should relax the thigh and hamstrings. The knee is commonly positioned around 20–30 degrees of flexion.

Examiner position

Stand beside the tested knee.

Hand placement

Stabilise the distal femur with one hand. Place the other hand around the proximal tibia.

Stabilisation

Keep the femur stable while the tibia is translated anteriorly.

Movement or force direction

Apply a controlled anterior force to the proximal tibia.

Instructions

Ask the client to relax and report pain, apprehension or familiar instability.

Positive finding

A positive finding may include increased anterior tibial translation, a soft or absent end-feel, apprehension or familiar instability compared with the other side.

Negative finding

A negative finding is no meaningful side-to-side increase in translation and a firm end-feel.

Stopping criteria

Stop if pain escalates, guarding prevents assessment or the test cannot be performed safely.

Safety notes

Use controlled force and avoid sudden jerks. Compare sides where appropriate.

Positive and Negative Test Interpretation

A positive Lachman Test may increase suspicion of ACL involvement when it matches the mechanism, swelling pattern, instability report and other ACL tests.

A negative Lachman Test reduces suspicion but does not fully exclude ACL injury, especially if pain, swelling, partial tear or guarding limits the test.

Interpretation is strongest when combined with pivot shift, anterior drawer, lever sign, effusion history, mechanism and functional findings.

Sensitivity, Specificity and Diagnostic Accuracy

A 2022 systematic review and meta-analysis reported that the diagnostic accuracy of ACL clinical tests may be lower than previously estimated and that the Lachman Test has been previously overestimated in some literature.  

Another 2022 systematic review focusing on acute ACL injury found evidence for Lachman, anterior drawer, pivot shift and lever sign tests remains limited and context-dependent.  

Because reported sensitivity and specificity values vary across acute and chronic settings, complete and partial tears, examiner experience and reference standards, use exact values only when the population and protocol match.

Reliability and Validity

Reliability depends on client relaxation, knee angle, hand size, examiner experience, force direction and side comparison.

Validity is strongest when the Lachman Test is interpreted within an ACL test cluster and matched to the injury history. It should not be used as the sole basis for diagnosis or clearance.

Common Errors and Limitations

Common errors include testing with hamstring guarding, poor femur stabilisation, pulling too distally, using too much knee flexion, not comparing sides, interpreting pain alone as laxity and failing to record end-feel.

Limitations include acute swelling, pain inhibition, partial tears, associated injuries and examiner-dependent technique.

Practical Applications

Use the Lachman Test to support ACL assessment, document anterior translation and guide decisions about referral, further testing and functional progression.

It is most useful with anterior drawer, pivot shift, lever sign, swelling assessment, knee ROM and functional testing.

How to Record This in Measurz

Record test name, side tested, result as positive, negative, unclear or unable to test, knee angle, pain score, symptom location, translation amount, end-feel, apprehension, guarding, swelling, comparison side, confidence in result and reason for stopping.

Related Tests / Internal Links

Anterior Drawer Test of the Knee
Lever Sign Test
Pivot Shift Test
Slocum Test
Posterior Drawer Test
Sweep Test
Single-Leg Hop Tests

FAQs

What does a positive Lachman Test mean?

It may suggest increased anterior tibial translation and possible ACL involvement when consistent with the broader assessment.

Does the Lachman Test diagnose an ACL tear?

No. It supports clinical reasoning but does not confirm ACL rupture on its own.

Why is end-feel important?

A soft or absent end-feel may be more meaningful than pain alone.

Is the Lachman Test better than the anterior drawer test?

It is commonly considered useful for ACL assessment, but recent evidence suggests diagnostic accuracy varies and should not be overestimated.

What should be recorded?

Record translation, end-feel, pain, guarding, knee angle and side comparison.

Key Takeaways

The Lachman Test assesses anterior tibial translation.
A positive result may increase suspicion of ACL involvement.
Recent reviews suggest accuracy may be lower than older estimates.
End-feel and side comparison are important.
Record findings and confidence in Measurz.

References

Huang, W., et al. (2022). The diagnostic accuracy of clinical tests for anterior cruciate ligament injury: A systematic review and meta-analysis. Knee Surgery, Sports Traumatology, Arthroscopy, 30, 3285–3295.

Tanaka, S., Inoue, Y., et al. (2022). Diagnostic accuracy of physical examination tests for suspected acute anterior cruciate ligament injury: A systematic review and meta-analysis. International Journal of Sports Physical Therapy, 17(5), 742–752.

Benjaminse, A., Gokeler, A., & van der Schans, C. P. (2006). Clinical diagnosis of an anterior cruciate ligament rupture: A meta-analysis. Journal of Orthopaedic & Sports Physical Therapy, 36(5), 267–288.