Postoperative results for the rotator cuff tear are good, but some cases with pain remain. A prior report described about clinical factors of persistent postoperative pain in rotator cuff tears, but we did not refer to the relationship of the postoperative pain and restoration of the rotator cuff in itself. This study determines whether postoperative pain in rotator cuff tear cases influences postoperative results and recovery of the rotator cuff. Among 151 rotator cuff tear patients, aside from those with massive tear, we extracted two groups according to the degree of pain at a one year postoperatively. The Painful group included 30 shoulders causing pain during activities of daily living (UCLA score of Pain < 6 points). The Painless group included 121 shoulders without pain (UCLA score of Pain = 10 points). For clinical evaluation, we examined the preoperative UCLA score and that at 1 year postoperatively. For the configuration evaluation, we estimated the muscle belly thicknesses of SSP, ISP, and deltoid muscles, and the fatty degeneration of SSP muscle on MRI. We compared each item at 6 months and 1 year postoperatively. In the improvement rate of the UCLA score, painless group was significantly higher than painful group. The thickness of ISP and deltoid muscle belly were more significantly improved at 1 year postoperative than at 6 months in the Painless group, but were not significantly improved in the Painful group. The SSP muscle belly was not significantly improved in either group. Fatty degeneration in each group was significantly more improved at 1 year postoperative than at 6 months. In the Painful group, both the improvement rate of postoperative results and the rotator cuff recovery were poor. Results show that pain during postoperative 1 year is inversely related with the index of improvement.
