Summary

The arthroscopic rotator cuff repair with muscle advancement and suprascapular nerve release to prevent postoperative neuropathy for massive rotator cuff tears can achieve good clinical outcomes without any cuff and scapular dysfunction by analysing radiographical and electromyographic study.

Abstract

Introduction

For small- to medium-sized rotator cuff tear (RCT), many authors reported good to excellent clinical outcomes as well as high anatomical healing rates after arthroscopic rotator cuff repair (ARCR). However, high failure rates after ARCR were often reported for large to massive RCT. We therefore perform ARCR with rotator cuff muscle advancement (MARCR) for the massive RCT to decrease the tension at the repair site and to reinforce the repaired cuff. However, suprascapular nerve (SSN) injury may occur due to excessive extraction of SSN with MARCR according to a previous report. Consequently, we add arthroscopic SNN release. The purpose of this study is to evaluate the postoperative peri-scapular function clinically, radiographically and neurologically after MARCR with SSN release.

Method

Fifty-two patients had undergone MARCR under diagnosis of massive RCT and their repaired tendons were confirmed completely healed through an MRI taken one year after surgery. An electromyographic (EMG) study to the supraspinatus (SSP) and infraspinatus (ISP) muscles innervated by SSN and deltoid was conducted preoperatively and more than 6 months after the surgery for all patients. When spontaneous potential at rest such as positive sharp wave and fibrillation potential, or decrease of interference wave in voluntary contraction were found, we regarded as positive denervation. We also evaluated the muscle edematous change and fatty degeneration with postoperative MRI taken 3, 6, and 12 months after surgery. Furthermore, we evaluated clinical outcomes assessed by Constant score and quantitative muscle strength, and compared statistically between the pre- and the postoperative condition.

Results

For preoperative EMG study, we found 17 positive denervation in the either SSP and/or ISP, that is, the ratio was 32.7%. For postoperative EMG study, 10 positive denervation was found. Of these 10 denervation, although 9 were the same compared to the preoperative results, only one of denervation in isolated ISP muscles were newly occurred. The muscle edematous changes observed in 41 cases of SSP and in 38 of ISP 3 months after surgery completely disappeared within 12 months after surgery. The Constant score improved significantly from 45.9 points to 77.4 points. Isometric muscle strengths of abduction, external and internal rotation, middle and inferior trapezius, and serratus anterior improved significantly after surgery (24.7 N, 32.3 N, 82.4 N, 84.3 N, 29.2 N and 28.1 N, to 57.1 N, 57.6 N, 113.6 N, 129.4 N, 44.3 N and 44.9 N, respectively).

Conclusions

SSP and ISP muscle changes that temporarily appeared three months after the MARCR completely disappeared six months after surgery, and fatty degeneration improved significantly three months after surgery. The clinical outcomes and muscle strengths improved significantly after surgery. Only one case was diagnosed with postoperative SSN neuropathy. Our methods can achieve good clinical outcomes without any scapular dysfunction.