Accuracy of preoperative MRI in the diagnosis of subscapularis tears.

Introduction: The subscapularis has received little attention in the orthopedic literature, although such lesions are evident in up to 40 % of arthroscopies. An accurate diagnosis is important in clinical practice, as it affects both patient prognosis and surgical planning. The aim of this study was to evaluate the accuracy of preoperative MRI for the identification of subscapularis tears. Our secondary aim involved the identification of factors that may be predictive for the presence of subscapularis tears.

Materials And Methods: This retrospective case series included patients undergoing shoulder arthroscopy due to rotator cuff injury. MRI was performed using a 1.5 T unit, and the results were assessed by a musculoskeletal radiologist. The findings were compared to those of arthroscopic inspection.

Results: A total of 93 shoulders were analyzed. The overall accuracy was 82 %, with values of 79 % for partial tears and 89 % for full-thickness tears. Tears requiring repair demonstrated an accuracy of 88 %. Infraspinatus tears, fatty degeneration of the subscapularis, biceps instability and age were identified as predictive factors for the presence of injury.

Conclusions: MRI of the shoulder demonstrated an accuracy of 82 % for the diagnosis of subscapularis tears. The accuracy values for partial and full-thickness tears were 79 and 89 %, respectively.

Level De Evidence: III, development of diagnostic criteria with universally applied reference-nonconsecutive patients.