MRI in the diagnosis of cartilage injury in the wrist

OBJECTIVE. Our purpose was to evaluate the accuracy of MRI in identifying articular cartilage abnormalities in the distal radius, scaphoid, lunate, and triquetrum of patients with wrist pain. MATERIALS AND METHODS. Eighty-six MRI examinations of the wrist in 85 patients (41 indirect MR arthrograms and 45 unenhanced [nonarthrographic] MR images) were evaluated. The study population consisted of 47 male (54.7%) and 38 female (45.3%) patients with an average age of 37.5 years (range, 7-62 years). Three experienced musculoskeletal radiologists who were unaware of surgical findings retrospectively evaluated the MRI examinations for cartilage abnormalities in the distal radius, scaphoid, lunate, and triquetrum. All patients underwent arthroscopy of the radiocarpal joint with inspection of the articular surfaces of the distal radius, scaphoid, lunate, and triquetrum. The articular cartilage was evaluated on the basis of the 5-point scale of the Outerbridge classification system. RESULTS. When at least two of the three radiologists had concordant interpretations, sensitivity for abnormalities in the distal radius was 27%; the scaphoid, 31%; the lunate, 41%; and the triquetrum, 18%. Specificity for the distal radius was 91%; the scaphoid, 90%; the lunate, 75%; and the triquetrum, 93%. Weighted kappa values among the three observers showed only fair agreement (0.279-0.360). High-grade more extensive cartilage lesions were no more accurately identified than low-grade lesions. Indirect MR arthrograms were not statistically more sensitive, specific, or accurate than unenhanced studies. No bone was more frequently or less frequently graded correctly or incorrectly with statistical significance. The variables of sex, age, and the presence of multiple bones with lesions did not affect accuracy. CONCLUSION. Our findings suggest that MRI of the wrist with the techniques described is not adequately sensitive or accurate for diagnosing cartilage defects in the distal radius, scaphoid, lunate, or triquetrum.