Daily Bolus of LR: McMurray Test for Meninscus Injury

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April 14, 2011 by dailybolusoflr

McMurray test

This test is performed to determine if there is a meniscus injury.

Simple tenderness along the joint line is not very sensitive, but experts agree that the McMurray test can assist you in better diagnosing this injury.

1.     Flex the hip and knee maximally

Medial Meninscus:

·         Place your finger along the joint line on the medial side

·         Apply a valgus force to the knee while externally rotating the foot and passively extending the knee.

·         An audible or palpable snap during extension suggests a tear of the medial meniscus.

Lateral meniscus:

·         Place your finger along the joint line on the lateral side

·         Apply a varus force to the knee while internally rotating the foot and passively extending the knee.

·         An audible or palpable snap during extension suggests a tear of the lateral meniscus.

You can watch a representation here
http://www.youtube.com/watch?v=fkt1TOn1UfI

 

COMPARING MANEUVERS

The following table compares the accuracy of specific physical examination maneuvers for the diagnosis of knee injuries. (Remember. .I am only providing you with one article…which is very supportive.  Not all LR are this high in other studies)

Probability of specific injury if:*


Physical exam maneuver

Positive Likelihood ratio+

Negative likelihood ratio

Exam maneuver is positive

Exam maneuver is negative

To diagnose meniscal injury:

Joint line tenderness

1.1

0.8

11%

8%

McMurray test

17.3

0.5

66%

5%


* Predictive values for each maneuver are based on a pretest probability of injury of 10 percent. If your clinical suspicion is higher or lower than this, then the probability would be correspondingly higher or lower.

+ The likelihood ratio indicates how well a positive test rules in disease or a negative test rules out disease. Positive likelihood ratios should be higher, while negative likelihood ratios should be lower.

 

Jackson  JL, O’Malley  PG, Kroenke  K.  Evaluation of acute knee pain in primary care.  Ann Intern Med. 2003;139:575–588

 

Linda Regan, MD FACEP

Program Director, Emergency Medicine Residency

Johns Hopkins Medical Institutions

 

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