Diagnostic value of MR arthrogram in SLAP lesions of the shoulder

Background: Superior labrum anterior to posterior (SLAP) lesions are important cause of shoulder pain and instability. MR Arthrogram is key investigation for assessment of these lesions. We aimed this study to evaluate the diagnostic performance of MR Arthrogram in SLAP tears.

Materials and methods: This was a retrospective study of 124 clinically diagnosed SLAP cases who had MR Arthrogram performed. Clinical, radiological and operative records were reviewed. MR Arthrogram findings were compared with arthroscopy. Those patients who did not undergo arthroscopy were not included in the final sensitivity analysis.

Results: Out of 124 cases, 54(43.54%) had normal MR Arthrogram, 32 (25.8%) had impingement or cuff related problems, 2 (1.61%) had Bankart lesions, and in 36 (29%) cases SLAP lesions were identified. Out of 54 patients with normal MR Arthrogram, 44 were discharged to physiotherapy and 10 underwent arthroscopy, showing SLAP lesion in one patient. Out of 32 patients with impingement or cuff problems, 19 were discharged to rehabilitation and 13 underwent surgery. Out of 36 patients with SLAP lesions, 5 recovered spontaneously, 5 were awaiting outpatient review and 26 underwent arthroscopy showing SLAP lesions in 22 cases. Overall, only 51 patients underwent arthroscopy. The MR Arthrogram was falsely positive in 4 cases (15.38%) and falsely negative in one case (3.84%). The sensitivity of MR Arthrogram was 95.6% (22/23), specificity 85.7% (24/28), positive predictive value 84.6% (22/26) and the negative predictive value was 96% (24/25).

Conclusion: MR Arthrogram is a useful technique for the diagnosis and preoperative planning of suspected SLAP lesions. It may also save patients from unnecessary diagnostic arthroscopy.