Prevalence of concomitant neuropathy in large to massive rotator cuff tear using needle electromyography

There have been few studies to evaluate the prevalence of other neuropathy, such as cervical spondylitic amyotrophy (CSAM), with rotator cuff tear (RCT). The purpose of this study was to define the prevalence of neuropathy combined with large to massive RCT using needle electromyogram. Three hundred forty-one patients who had symptomatic RCT were enrolled in this study, (large size tear; 224 cases and massive tear; 144 cases.) All cases were examined by needle electromyogram before surgery. Prevalence of neuropathy was as follows; Large tear; 30 cases of suprascapular neuropathy (13.4%), 1 case of axillary nerve palsy (0.4%) and 20 cases of cervical spondylitic amyotrophy (8.9%), Massive tear; 36 cases of suprascapular neuropathy (25.0%), 1 case of axillary nerve palsy (0.7%) and 55 cases of CSAM (38.2%). Furthermore, there were 82 cases of pseudo-paralyzed shoulders in the massive RCT group. Among those 82 shoulders, 40 shoulders (48.8%) had CSAM, 16 shoulders (19.5%) had suprascapular neuropathy and 1 shoulder (1.2%) had axillary nerve palsy. Prevalence of neuropathy combined with massive RCT in pseudo-paralyzed shoulders was considered to be very high. The prevalence of massive RCT concomitant with CSAM was very high. Our results showed that the fatty infiltration of rotator cuff muscle became worse in large to massive RCT because of the combination of disuse due to the RCT and paralysis due to neuropathy. Careful neurogenic screening is recommended in patients with large to massive RCT, especially in patients who cannot actively elevate shoulders less than 90°.