Abstract
We previously reported that MRI low signal intensity changes at the rotator cuff insertion six months and one year postoperatively indicate restoration of the rotator cuff after repair. We now investigate possible associations between certain preoperative factors and MRI low signal intensity changes at the rotator cuff insertion within the first two postoperative years. The study group comprised 270 shoulders that had undergone rotator cuff repair. We divided the shoulders into two groups: 231 shoulders with simultaneous rotator cuff low signal intensity changes within the first two years after repair and 39 shoulders with no signal intensity changes within the first two years after repair. We analyzed the following preoperative factors: JOA score, UCLA score, range of motion (ROM) of the shoulder, manual muscle test (MMT) of the shoulder, and rotator cuff tear size at the time of operation. Preoperative tear size and preoperative muscular strength of lateral rotation showed significant correlation with MRI signal intensity changes within the first two postoperative years:r=0.534, p<0.0001 and r=0.477, p<0.0001, respectively. No significant correlations were observed between UCLA score, JOA score, or shoulder ROM and MRI signal intensity changes within the first two postoperative years. We conclude from our comparison of the two study groups that cases with tear size ≤3.0cm or cases with external rotation muscular strength more than MMT4 very likely will subsequently exhibit low intensity changes at the rotator cuff insertion within the first two postoperative years.
