The Association Between The Improvement Of Muscle Atrophy And Fatty Infiltration And Postoperative Functional Outcomes After Arthroscopic Rotator Cuff Repair(ARCR)

Objective:To evaluate the improvement of rotator cuff muscle atrophy and fat infiltration by successful shoulder arthroscopy rotator cuff repair in patients with rotator cuff muscle atrophy and fat infiltration,the association between the improvement of muscle atrophy and fatty infiltration and postoperative functional outcomes after arthroscopic rotator cuff repair(ARCR)needs to be investigated.Methods:A retrospective analysis of 44 patients who underwent arthroscopic surgery to repair rotator cuff tears from September 2016 to September 2017 was performed.According to the patient’s rotator cuff tear size,it was divided into partial tear,small tear group(6 cases),moderate tear group(23 cases),large tear and huge tear group(15 cases).MRI imaging of 1 year and 2 weeks after operation was performed to observe the improvement of muscle atrophy and fat infiltration in the 3 groups after operation.The statistical results showed 31 cases of rotator cuff muscle atrophy improvement group,13 cases of unimproved group,and 28 cases of rotator cuff fat infiltration improvement group,16 cases were not improved.Comparison of rotator cuff muscle atrophy and fat infiltration improvement group and unimproved group were maked respectively at postoperative 1 year about visual analogue scale(VAS),shoulder range of motion(Range of Motion,ROM),supraspinatus muscle abduction and external Spinning muscle strength,Constant-Murley score,and the University of California at Los Angeles(UCLA).Results:(1)All patients were followed up for 1 year.(2)The ratio of supraspinatus at postoperative 1 year in the partial small tear and moderate tear groups was significantly increased,while the large and huge tear group showed no significant changes.(3)The degree of fat infiltration in the rotator cuff was significantly improved in all(4)patients.All patients had a lower visual analog score for shoulder pain after 1 year of operation.The shoulder-score scores of Constant-Murley and UCLA increased,and the shoulder joint activity and supraspinatus muscle strength recovered significantly.The difference was significant(P(5)< 0.01).Compared with the group with no improvement in rotator cuff muscle atrophy,the muscle atrophy improvement group has better range of abduction,stronger abduction intensity,higher Constant-Murley score and UCLA shoulder score.(P(6)< 0.05).Compared with the group without improvement of the rotator cuff fat infiltration,the postoperative fat infiltration improvement group had a better range of flexion and a larger range of abduction and lifting motion.Conclusion:Muscle atrophy in the partial small tear and moderate tear groups undergoing arthroscopic surgery is significantly improved,but the large tear and huge tear groups are difficult to improve.Patients with improved supraspinatus muscle atrophy increase the upper extremity abduction activity,improve the superior abductor muscle strength and shoulder function score.No matter the size of the rotator cuff tear,fat infiltration will improve after successful shoulder arthroscopy rotator cuff repair.The improvement of fat infiltration can increase the flexion and abduction activity,but it can not improve the abductor muscle strength and shoulder function score.