Physical Exam and Magnetic Resonance Imaging (MRI) in the Diagnosis of Superior Labrum Anterior-Posterior (SLAP) Lesions of the Shoulder (SS-50)

Abstract

There is limited data comparing the sensitivity of physical examination and MR imaging in the diagnosis of arthroscopically confirmed glenoid labral lesions. A review of 50 consecutive patients with arthroscopically confirmed superior labrum anterior-posterior (SLAP) lesions and no history of shoulder dislocation was performed. The study was prospectively designed with IRB approval. All patients underwent a standardized physical examination that was compared to the official radiologist’s report of MR and/or MR arthrogram imaging. Sensitivity analysis was performed. To determine a difference in sensitivity of 8% between testing modalities, a pre-study power analysis determined that the minimal sample size was 25 patients (for a study with a power of 0.80 and an alpha of 0.05). The sensitivity of O’Brien’s active compression test was 90%, whereas the Mayo (dynamic) shear was 80% and Jobe’s relocation test was 76%. The sensitivity of a physical exam with any one of these three tests being positive was 100%; the sensitivity of requiring at least two positive tests ranged from 64% - 72%, and the sensitivity decreased to 58% if all three of these maneuvers was deemed necessary for the diagnosis. Neer (42%) and Hawkin’s impingement tests (32%) each had low sensitivity for SLAP lesions. The sensitivity of MRI for SLAP lesions was 68% when interpreted by the performing surgeon, 54% when read by a radiologist. When the gadolinium enhanced MRI’s were analyzed as a subset (performed in 17 patients), the sensitivity was 76% (surgeon) and 52% (radiologist), respectively. O’Brien’s test was highly sensitive while the Mayo shear and Jobe’s relocation tests had good sensitivity in the diagnosis of SLAP lesions. MR and MR arthrogram imaging had a lower sensitivity than these examination tests in diagnosing SLAP lesions. Patient history and physical examination remain central to the diagnosis of glenoid labral lesions. While MRI is not as sensitive, it remains an adjunct for the clinician in treating these patients.