Lachman Test
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Purpose
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The Lachman's test is a passive accessory movement test of the knee which is performed to identify the integrity of the anterior cruciate ligament or ACL. The test is designed to assess single sagittal plane instability.
Technique
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Lay the patient supine on a bed. Put the patient's knee in about 20-30 degrees flexion, also according to Bates' Guide to Physical Examination the leg should be externally rotated. The examiner should place one hand behind the tibia and the other on the patient's thigh. It is important that the examiner's thumb be on the tibial tuberosity. On pulling anteriorly on the tibia, an intact ACL should prevent forward translational movement of the tibia on the femur ("firm endpoint").
Anterior translation of the tibia associated with a soft or a mushy endpoint indicates a positive test. More than about 2 mm of anterior translation compared to the uninvolved knee suggests a torn ACL ("soft endpoint"), as does 10 mm of total anterior translation. An instrument called a "KT-1000" can be used to determine the magnitude of movement in mm.
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Evidence[edit | edit source]
[3] reported that the Lachman test has a diagnostic accuracy of acute ACL ruptures (within 2 weeks of examination) of: 77.7% sensitivity and >95% specificity. The study reported the diagnostic accuracy of subacute/chronic ACL ruptures (more than 2 weeks before examination) is: 84.6% sensitivity and >95% specificity. It is important to note that in this study all examinations were performed under anesthesia; thus the diagnostic accuracy in physiotherapy clinical practice may be less.
Other special tests with the purpose of diagnosing ruptures of the anterior cruciate ligament (ACL) by testing it's integrity include: the knee anterior drawer test and the pivot shift test.
Resources[edit | edit source]
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Recent Related Research (from Pubmed)[edit | edit source]
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References[edit | edit source]
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- ↑ Scott Holmes and Eric Sorenson, Lachmans Test, http://www.youtube.com/watch?v=bHytLhg-1vM, online video, last accessed 30 November 2009
- ↑ Ithaca College, Lachman Test, http://www.youtube.com/watch?v=_5WyoDY31Fc, online video, last accessed 30 November 2009
- ↑ Katz JW, Fingeroth RJ. The diagnostic accuracy of ruptures of the anterior cruciate ligament comparing the Lachman test, the anterior drawer sign, and the pivot shift test in acute and chronic knee injuries. The American Journal of Sports Medicine 1986;14:88-91. fckLRhttp://ajs.sagepub.com/content/14/1/88.short (accessed 18 July 2013)
