Lachman Test

Published July 2, 2026 Read time 1 min read Readers 1
Lachman Test

What is the "Lachman Test" used for?

  • Assess the integrity of the anterior cruciate ligament (ACL)

How to perform the "Lachman Test"?

  • The patient is positioned supine with the injured knee flexed to 20 to 30 degrees while also slightly externally rotating the injured leg to relax the iliotibial band.
  • The examiner then uses one hand to stabilize the distal femur while using the other hand to grasp the proximal tibia.
  • Next, an anterior force is applied to the proximal tibia in an attempt to sublux the tibia forward while keeping the femur stabilized

What is the positive result?

  • The test is considered positive if there is excessive anterior translation of the proximal tibia greater than the uninjured side and also a lack of a firm endpoint.
  • Endpoints are graded from “hard” to “soft,” and have been nominally classified as :
    • A (firm, hard endpoint)
    • B (absent, soft endpoint).

Test Accuracy

  • Sensitivity: 87 %
  • Specificity: 93 %

References

  • Dutton’s Orthopaedic Examination, Evaluation, And Intervention 3rd Edition.
  • NCBI – Skills in Rheumatology