Predictive Factors of Retear in Patients With Repaired Rotator Cuff Tear on Shoulder MRI

OBJECTIVE. This study aimed to find independent prognostic factors related to retear of the rotator cuff tendon in patients with repaired full-thickness supraspinatus tendon tear by evaluation of pre- and postoperative MR images. MATERIALS AND METHODS. Shoulder MR images were retrospectively analyzed for 83 patients who had undergone arthroscopic or open rotator cuff repair with acromioplasty for full-thickness supraspinatus tendon tear from April 2014 to March 2015. On preoperative MR images, the type of rotator cuff tear, extent of retraction of torn tendon, anteroposterior (AP) dimension of torn tendon, signal intensity of tear edge, degree of fat infiltration in supraspinatus and infraspinatus muscles, and acromiohumeral interval (AHI) were assessed. Postoperative cuff integrity seen on MR images was classified into five categories according to the Sugaya classification system, and patients were categorized into retear or intact groups. Factors assessed on preoperative MR images were compared between the two groups. RESULTS. The overall retear rate was 57.8%. Significant differences were observed between the retear and intact groups in terms of the mean values of the extent of tendon retraction (20.4 vs 11.7 mm), AP dimension of the tear (16.1 vs 11.4 mm), AHI (6.8 vs 8.7 mm), and degree of fat infiltration of the supraspinatus and infraspinatus muscles (for the supraspinatus muscle, 3, 30, and 15 patients in the retear group vs 5, 27, and three patients in the intact group had Goutallier grade 1, grade 2, and grades 3 and 4 infiltration, respectively; for the infraspinatus muscle, 27, 12, and 9 patients in the retear group vs 29, 5, and one patient in the intact group had Goutallier grade 1, grade 2, and grades 3 and 4 infiltration, respectively). Multivariable analysis revealed that AHI and degree of tendon retraction were independent predictive factors affecting retear of rotator cuff after repair. CONCLUSION. The retear rate of repaired rotator cuff tendon was about 57.8%. Independent prognostic factors of retear were degree of tendon retraction and AHI on preoperative MR images.