Anterior Cruciate Ligament Tear: Likelihood Ratios

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The likelihood ratios of findings for Anterior Cruciate Ligament Tear are listed below. See the left navigation bar to change the display.

Good Positive and Negative Likelihood Ratios

Finding	+LR	-LR	Comments, Study
Lachman Test	12.4	0.1	pull anteriorly when knee is flexed at 30 degrees Study: Ann Intern Med. 2003 Oct 7;139(7):575-88. PMID: 14530229
MRI	9.7	0.1	Study: Ann Intern Med. 2003 Oct 7;139(7):575-88. PMID: 14530229 Systematic review. Radiology 2003 PMID: 12601211
Anterior drawer test as measured by the KT-1000 arthrometer	7.7	0.3	The sensitivity and specificity will vary based on the amount of force applied and the threshold chosen for anterior tibial motion. These numbers above are for a 30 lbs test with >3mm as diagnostic threshold for ACL tear. Study: PMID 19398799
Pivot Test	20.3	0.4	Fully extend the knee, rotate the foot internally. Apply a valgus stress while progressively flexing the knee, watching and feeling for translation of the tibia on the femur. Study: Ann Intern Med. 2003 Oct 7;139(7):575-88. PMID: 14530229

Good Positive Likelihood Ratio

Anterior Drawer Test

3.7

0.6

pull anteriorly when the knee is flexed at 90 degrees

Note that when the anterior drawer test has been studied using the KT-1000 arthrometer. This provides an objective measure to the anterior drawer test. When performed with the KT-1000 arthrometer, the sensitivity and specificity will vary based on the amount of force applied and the threshold chosen for anterior tibial motion. For a 30 lbs test with >3mm as diagnostic threshold for ACL tear the sensitivity and specificity have been reported as 77% and 90%.

The anterior drawer test has been studied with objective measurements using ultrasonography. The sensitivity and specificity were reported as 96% and 98% though the cut off displacement distance appears to have been decided upon after the data was examied. See PMID 10401653

Study: Anterior drawer test: Ann Intern Med. 2003 Oct 7;139(7):575-88. PMID: 14530229

KT-1000 Arthrometer: PMID 19398799

Ultrasound: PMID 10401653