Summary

Payr’s sign is a highly predictive examination maneuver for suspected posterior root tears of medial meniscus, in patients with early to moderate knee osteoarthritis,

Abstract

Introduction

Posterior root tears of medial meniscus (PRTMMs) are not uncommon in middle-aged and older Asian population. Over the years several clinical tests have been described to diagnose meniscal disorders. Yet, till date no test has been evaluated to specifically diagnose PRTMMs. We want to describe the use of a classic clinical test - Payr’s sign to detect posterior root tears of medial meniscus. The purpose of this prospective study was to determine the accuracy, sensitivity, specificity, and predictive values of Payr’s sign and to compare it’s diagnostic value with medial joint line tenderness (MJLT) and McMurray’s test in patients with early to moderate knee osteoarthritis.

Methods

In a prospective study, 530 patients with symptoms related to the knee joint were seen at our clinic between March and September 2015. Adults over 40 years of age, with acute onset or aggravation of mechanical medial-sided knee pain (less than 8 weeks prior to clinic review), with early clinical and radiographic signs of osteoarthritis were included. Exclusion criteria were patients with history of significant trauma or prior knee surgery, and/or severe degenerative changes on standing radiographs (Kellgren-Lawrence grade III or IV). A knee surgery fellow recorded results of three tests: MJLT, McMurray’s test, and Payr’s sign. All patients underwent 3.0 Tesla Magnetic Resonance Imaging (MRI) scans. Root tear was defined as a radial tear that occurs within 1 cm of the posterior horn insertion. MRI findings were reported by a single experienced musculoskeletal radiologist, accepted as final diagnosis and correlated with results of the meniscus tests.

Results

63 knees of 61 patients (57 female and 4 male) with a mean age of 52 years (range; 41-68 years) and mean BMI of 31.0 (range; 21.4-44.9) met the inclusion criteria. All patients had mechanical knee pain on an average formulaes (range, 2 to 54 days) with grade I or II changes on standing AP radiographs. On MRI, 22 knees were diagnosed with PRTMMs. 14 out of these 22 knees underwent arthroscopy, where findings were in agreement with those of MRI, confirming root tears in all patients. Payr’s sign showed the highest values for sensitivity- 86.36%, specificity- 90.24% and diagnostic accuracy- 88.88% in the diagnosis of PRTMMs. It had a positive predictive value of 82.61% [95% CI: 61.2-95.1%] and a negative predictive value of 92.5% [95% CI: 79.6-98.4%]. MJLT and McMurray’s test showed inferior diagnostic accuracy values of 26.98% and 60.32% respectively and a higher number of false-negative and false-positive recordings. In fact, combining results of the three examination maneuvers performed worse (diagnostic accuracy-69.84%) than using Payr’s sign alone.

Conclusion

The results of our study highlight the importance of Payr’s sign in the diagnosis of PRTMMs. Other tests, when used alone or in combination, are of little clinical value to detect PRTMMs. In patients with early to moderate knee osteoarthritis, Payr’s sign is a highly predictive examination maneuver for suspected posterior root tears of medial meniscus.