Early postoperative magnetic resonance imaging findings after arthroscopic rotator cuff repair: T2 hyperintensity of the capsule can predict reduced shoulder motion.

Abstract

The purpose of this study was to investigate whether postoperative shoulder magnetic resonance imaging (MRI) findings correlate with postoperative shoulder range of motion (ROM) at about 4 months after arthroscopic rotator cuff repair (ARCR). Signal-intensity changes of the capsule, pericapsular soft tissue at the axillary recess, and subcoracoid fat triangle, as well as the thickness of the capsule at the axillary recess and coracohumeral ligament were assessed on preoperative and postoperative MR images of 232 patients. The ROM was evaluated preoperatively and at about 4 months after ARCR. T2 hyperintensity of the capsule, pericapsular soft tissue at the axillary recess, and signal change of the subcoracoid fat triangle were detected in 155, 107, and 89 cases, respectively, on postoperative MRI. Among these cases, 129, 98, and 69 cases, respectively, showed newly developed signal changes. The mean thicknesses of the capsule and coracohumeral ligament were 1.89 ± 0.69 and 1.64 ± 0.51mm, respectively, on preoperative MRI and 3.74 ± 1.12 and 2.42 ± 0.56mm, respectively, on postoperative MRI. At the 4-month follow-up, the mean external rotation (ER), internal rotation (IR), abduction, forward flexion, and extension were 77, 73, 76, 83, and 82%, respectively, of the contralateral side. Newly developed T2 hyperintensity of the capsule and pericapsular soft tissue at the axillary recess on postoperative MRI significantly correlated with the postoperative limitation of ER (p = 0.039) and IR (p = 0.020). Newly developed signal changes of the capsule, pericapsular soft tissue at the axillary recess, and subcoracoid fat triangle were often detected on postoperative MRI at 4 months after ARCR. Furthermore, newly developed T2 hyperintensity of the capsule and pericapsular soft tissue at the axillary recess correlated with limited ROM in ER and IR at 4 months after ARCR.