Reversibility of Supraspinatus Muscle Atrophy in Tendon-Bone Healing After Arthroscopic Rotator Cuff Repair

Abstract

Background: To date, there are few reports of the definite reversibility of rotator cuff muscle atrophy after repair. Purpose: To evaluate the reversibility of rotator cuff muscle atrophy after successful arthroscopic repair. Study Design: Case series; Level of evidence, 4. Methods: Included in this study were 47 patients (mean age, 61.2 7.3 years; range, 49-73 years) who underwent arthroscopic rotator cuff repair as well as magnetic resonance imaging (MRI) preoperatively and at 6-month and last follow-up. Patients who had confirmed rotator cuff healing (grades 1-3 according to the Sugaya classification) on both series of postoperative MRI were enrolled in the study. The mean time from the onset of symptoms to surgery was 24.7 25.6 months (range, 3-120 months). The minimum follow-up was 2 years, and the mean follow-up duration was 41.8 +/- 14.4 months. Serial changes in the supraspinatus muscle area on the most matching MRI scans (sagittal-oblique view) were evaluated. The area was measured by 2 independent observers. Results: Both independent observers reported no significant difference in the area of the supraspinatus muscle between the preoperative time point and 6-month follow-up (observer 1: P = .135; observer 2: P = .189). However, there was a significant difference between the 6-month and last follow-up (mean, 41.8 months; observers 1 and 2: P < .001). The serial changes in the area preoperatively and at 6-month and last follow-up were 419.41 +/- 122.97 mm(2), 431.76 +/- 104.27 mm(2), and 466.73 +/- 121.42 mm(2), respectively (observer 1), and 421.01 +/- 116.61 mm(2), 432.56 +/- 100.78 mm(2), and 469.84 +/- 113.80 mm(2), respectively (observer 2). The intraclass correlation coefficient between the 2 observers was 0.988. At final follow-up, the area increase on the medial and lateral aspects of the sagittal-oblique view compared with preoperatively was 13.9% (P < .001) and 11.3% (P < .001), respectively. Fatty infiltration did not change from preoperatively to 6-month follow-up (P > .999) or from 6-month to final follow-up (P = .077). Conclusion: After successful arthroscopic rotator cuff repair, there was a slight (11.3%-13.9%) increase in muscle volume from preoperatively to final follow-up, as seen on serial MRI. Fatty infiltration according to the Goutallier grade was not reversed (P = .077). Some reversibility of supraspinatus muscle atrophy may exist in tendon-bone healing after arthroscopic rotator cuff repair; further follow-up is needed to better elucidate this result.