肩腱板断裂の術後 1 ヵ月の MRI で再断裂は予想できるか

抄録

To determine postoperative early MR findings of the repaired rotator cuffs, which predict future re-tear, we evaluated MRI taken 1 month after arthroscopic rotator cuff repair (ARCR). From February 2005 to February 2008, 29 patients with 29 cuff tears underwent ARCR using dual-row fixation. There were 21 men and 8 women with the average age of 62 years old. The tear size was medium in 7 patients, large in 19, and massive in 3. Postoperatively MRI was taken twice, first at 1 month and second at 3 months or later (average 5.1 months). None of the 29 patients showed re-tear of the cuff in the first postoperative MRI, whereas 7 patients exhibited re-tear in the second postoperative MRI. These 7 patients were referred to as the re-tear group. The remaining 22 patients were referred to as the repair group. Between 2 groups, MR findings at 1 month postoperatively were compared with respect to cuff integrity, cuff thickness at the top of the humeral head and the greater tuberosity, difference of the cuff thickness between at the top of the humeral head and the greater tuberosity, fatty degeneration of rotator muscles, atrophy of the supraspinatus muscle, and effusion of the gleno-humeral joint, the subacromial bursa, and the bicepital groove. Based on the Mann-Whitney's U test and the Fisher's exact probability test, data with p-values of less than 0.5 were regarded as statistically significant differences. Among several parameters examined in 2 groups, significant differences were found in the cuff thickness at the greater tuberosity, and the difference of the cuff thickness between at the top of humeral head and greater tuberosity. These 2 parameters likely reflect retraction of the repaired cuff medially. Such medial retraction of the repaired cuff at 1 month postoperatively may serve as a predictive MR feature for future re-tear.