Meniscus Tear: Likelihood Ratios

Introduction: A tear of the lateral or medial menisci of the knee joint, usually traumatic.

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

Pre-Test Probability (Prevalence): %.	Post-Test Probability (Predictive Value): %.	Switch to display mode.
Note that calculating probabilities from more than one** finding is inherently inaccurate because findings are not independent. (For example, using two positive findings that share a common pathogenesis is likely to overestimate the true probability.)

Good Positive and Negative Likelihood Ratios
Finding	Result	+LR	-LR
[ + ] MRI	+ 0 -	5.6	0.2
sensitivity lower for LM, specificity lower for MM Study: Ann Intern Med. 2003 Oct 7;139(7):575-88. PMID: 14530229 Systematic review. Radiology 2003 PMID: 12601211
[ + ] McMurray Test	+ 0 -	17.3	0.5
Flex the hip and knee maximally. Apply a valgus (abduction) 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. For the lateral meniscus, apply a varus (adduction) stress during internal rotation of the foot and passive extension of the knee. Study: Ann Intern Med. 2003 Oct 7;139(7):575-88. PMID: 14530229