Objective: The objective of this study was to investigate the diagnostic performance of MR arthrography after rotator cuff repair.
Materials and methods: MR arthrographic examinations of the shoulder performed after rotator cuff repair and before revision surgery were retrospectively analyzed in 48 patients (31 males, 17 females; mean age, 50.3 years; age range, 17-69 years). Full-thickness and partial-thickness defects of the supraspinatus, infraspinatus, and subscapularis tendons were diagnosed independently by two radiologists. Revision surgery served as the standard of reference.
Results: Observer 1 correctly recognized five of eight intact supraspinatus tendons, 10 of 19 partial-thickness defects, and 19 of 21 full-thickness defects. For observer 2, the numbers were three of eight, eight of 19, and 18 of 21. The corresponding numbers for the infraspinatus tendon for observer 1 were 28 of 31, 0 of three, and 14 of 14 tendons. For observer 2, they were 28 of 31, two of three, and 11 of 14. For the subscapularis tendon, observer 1 made the correct diagnosis in 18 of 31, five of six, and nine of 11 tendons. The results for observer 2 were 26 of 31, one of six, and 10 of 11 tendons. Interobserver agreement (weighted kappa) was 0.47 for the supraspinatus, 0.64 for the infraspinatus, and 0.20 for the subscapularis tendons, respectively.
Conclusion: Postoperative full-thickness defects of the rotator cuff are reliably diagnosed with MR arthrography. The diagnostic performance for partial-thickness defects is only moderate.