Knee Orthopaedic Test: Lachman Test

The Lachman test is a clinical examination used to assess the integrity of the anterior cruciate ligament (ACL) in the knee joint. The procedure is relatively simple and involves the following steps:

1. Position the patient lying flat on their back with the affected knee bent at a 20-30 degree angle.
2. With one hand, grasp the distal end of the femur (thigh bone) just above the knee joint.
3. With the other hand, grasp the proximal end of the tibia (shin bone) just below the knee joint.
4. With the knee in a slightly flexed position, use your hands to apply a forward force on the tibia while simultaneously stabilizing the femur.
5. Assess the degree of anterior translation (forward movement) of the tibia relative to the femur.
6. Compare the degree of anterior translation with the unaffected knee or with normal values.
7. The presence of excessive anterior translation may indicate a tear or laxity of the ACL.

A normal result of the Lachman test would be minimal to no anterior translation of the tibia when compared to the contralateral knee or normal values. However, the amount of anterior translation that is considered normal may vary depending on the individual and other factors, such as age and activity level.

References:

1. Solomon, D. H., Simel, D. L., & Bates, D. W. (2001). The rational clinical examination. Does this patient have a torn meniscus or ligament of the knee? Value of the physical examination. Jama, 286(13), 1610-1620. doi: 10.1001/jama.286.13.1610
2. Daniel, D. M., Stone, M. L., Dobson, B. E., Fithian, D. C., Rossman, D. J., & Kaufman, K. R. (1994). Fate of the ACL-injured patient: A prospective outcome study. The American Journal of Sports Medicine, 22(5), 632-644. doi: 10.1177/036354659402200511
3. Lubowitz, J. H., Schwartzberg, R., Smith, P., & Appleby, D. (2015). The lachman test is the most sensitive and the pivot shift the most specific test for the diagnosis of ACL rupture. Knee surgery, sports traumatology, arthroscopy, 23(4), 998-1002. doi: 10.1007/s00167-014-3131-6
4. Kopka, M., Bradley, J. P., & Bush-Joseph, C. A. (2009). The diagnosis of an acute anterior cruciate ligament tear in skeletally immature individuals. Arthroscopy: The Journal of Arthroscopic & Related Surgery, 25(6), 634-640. doi: 10.1016/j.arthro.2009.01.026
5. Duffee, A., Magnussen, R. A., Pedroza, A. D., Flanigan, D. C., & Kaeding, C. C. (2013). The efficacy of diagnostic arthroscopy for evaluating intra-articular knee pathology in patients with normal plain radiographs and MRI scans. The Iowa Orthopaedic Journal, 33, 7-11. PMID: 23802003