A systematic approach for diagnosing subscapularis tendon tears with preoperative magnetic resonance imaging scans.

PURPOSE: To determine and propose a systematic approach to evaluating magnetic resonance imaging (MRI) scans for subscapularis tears and compares preoperative MRI interpretations with findings of the same shoulders at arthroscopy.

METHODS

The study was composed of 202 patients who underwent shoulder arthroscopy by 1 of 5 orthopaedic surgeons during a 3-month period. All patients had MRI scans performed within 6 months before arthroscopy.

RESULTS

Of the 202 patients, 82 had subscapularis tendon tears confirmed at the time of arthroscopy. The orthopaedic surgeons correctly diagnosed 60 of 82 patients (73%) with subscapularis tendon tears on preoperative MRI that were subsequently identified by arthroscopy. The orthopaedic surgeons correctly diagnosed 113 of 120 patients (94%) as not having subscapularis tendon tears. This resulted in an overall sensitivity of 73%, specificity of 94%, positive predictive value of 90%, negative predictive value of 84%, and accuracy of 86%. The frequency of subscapularis tears was highest when the long head of the biceps was displaced from the groove (88%), a combined supraspinatus/infraspinatus tear existed (71%), or the long head of the biceps tendon was torn (69%).

CONCLUSIONS

Preoperative MRI scans of the shoulder interpreted by orthopaedic surgeons with the described systematic approach resulted in improved accuracy in diagnosing subscapularis tendon tears compared with previous studies. A consistent finding is that larger subscapularis tendon tears are more easily detected using MRI scans whereas smaller tears are more frequently missed.

LEVEL OF EVIDENCE: Level III, development of diagnostic criteria with universally applied reference (nonconsecutive patients).