Does change in occupancy ratio and fatty infiltration of the supraspinatus influence functional outcome after single-row rotator cuff repair? A magnetic resonance imaging–based study

The purpose of this study was to analyze the correlation of occupancy ratio (OR) and fatty infiltration (FI) to functional outcome and retear rate following rotator cuff repair by single-row technique. Retrospectively, all the patients (n = 100) with rotator cuff tear were evaluated preoperatively and postoperatively with functional scores (American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form [ASES], University of California–Los Angeles [UCLA] shoulder score, Constant score) and magnetic resonance imaging (MRI) for OR and FI. Two observers studied the MRI data separately. Statistical analysis was done using SPSS (version 16), paired t test, Pearson correlation, and intraclass correlation coefficients. The mean (± standard deviation) follow-up was 16.24 ± 6.39 months, and the mean age was 56.18 ± 7.5 years. There was a significant increase in muscle atrophy (decreased OR) and FI (P < .01). The mean preoperative and postoperative ORs were 0.57 and 0.51, respectively. However, the mean functional scores improved significantly for ASES (55.78 to 82.09), UCLA (19.44 to 28.47), and Constant score (49.73 to 75.07) (P < .001). There was no significant difference in functional outcome among the different stages of FI (ASES P = .341, UCLA P = .839, Constant P = .376). Seven patients had asymptomatic retear during follow-up, of which 2 patients had grade 3, 4 patients had grade 2, and 1 patient had grade 1 FI, preoperatively. Muscle atrophy and FI are irreversible phenomena and continue even after successful repair; however, they do not have a significant influence on the functional outcome at short-term follow-up after cuff repair. Repairing cuff with higher grades of FI can be performed as they achieve significantly improved functional outcomes.