MR evaluation of subscapularis tears

Purpose: The purpose of this work was to describe the NR appearance of tear s of the subscapularis tendon and compare the usefulness of different imagi ng planes as well as note the association of subscapularis tears with other rotator cuff tears and biceps tendon dislocations. Method: MR studies at 1.5 T over an 8 year interval were retrospectively as sessed for the presence of a rotator cuff tear and/or tear of the subscapul aris tendon. Images that showed a subscapularis tear were reviewed for the presence of a visible tear separately on the axial, coronal, and sagittal i mages. The MR studies were also evaluated for associated tears of the supra spinatus, infraspinatus, and teres minor muscles as well as biceps tendon d islocation and the "naked humerus sign" on coronal images. Last, clinical r ecords and surgical reports were reviewed. Results: Forty-five (2%) of 2,167 rotator cuff tears involved the subscapul aris; 27% were partial and 73% were complete tears. Tears were best seen in the sagittal oblique plane. Almost all subscapularis tears were an extensi on of typical rotator cuff tears: supraspinatus in 35 patients (79%), exten ding into infraspinatus tears in 25 (56%) and into teres minor tears in 2 p atients (4%). Bicipital dislocations were seen in 22 patients (49%), and th ree complete tears of the biceps (7%) were noted as well. The naked humerus sign was demonstrated in 31 patients (69%). Surgical reports that confirme d the MR findings were available for 15 patients. Conclusion: About 2% of rotator cuff tears involve the subscapularis tendon . Most subscapularis tears are extensions of supraspinatus tears and freque ntly involve the biceps tendon.