Paradoxical phenomena of the McMurray test. An arthroscopic investigation.

We evaluated 200 patients who had a positive McMurray test and found atypical McMurray test results in 24 patients (12%). These patients revealed pain or clicking or both either in the medial compartment of the knee when the leg was internally rotated or in the lateral compartment of the knee when the leg was externally rotated. The authors analyzed these paradoxical findings at arthroscopic examination to identify the relationship between the type of meniscal tear and the direction of leg rotation that elicited the catching and displacement of the torn meniscal portion during the McMurray test. Contrary to conventional McMurray test findings, three different types of meniscal tears were found on the side of the knee where pain or a clicking sound occurred. The three types were 1) anteriorly based posterior oblique tears with anterior displacement of the meniscus, 2) bucket-handle tears in the posterior half of the menisci, and 3) peripheral detachment of discoid menisci in the posterior half of the torn portions.