Prevalence of rotator cuff tear concomitant with neuropathy: analysis of 659 cases using needle electromyography

Rotator cuff tears (RCTs) are highly prevalent and increase with age. Although suprascapular neuropathy associated with RCTs has been increasingly reported, the prevalence of other neuropathies, including cervical radiculopathy and brachial plexopathy, remains unclear. Furthermore, the relationship among neuropathy, tear size, and shoulder pseudoparalysis remains incompletely understood. This study aimed to determine the prevalence of neuropathies associated with RCTs using needle electromyography (EMG) and examine their relationship with tear size and pseudoparalysis.

A total of 659 patients with surgically treated magnetic resonance imaging-confirmed RCTs between 2012 and 2014 were included in the study. All patients underwent pre-operative needle EMG. Neuropathy was classified as suprascapular neuropathy, axillary nerve palsy, or proximal neuropathy (cervical radiculopathy or brachial plexopathy). Tear size was categorized as subscapularis, partial thickness, small, medium, large, or massive. Pseudoparalysis was defined as active shoulder elevation ≤90°. Statistical analyses included one-way analysis of variance and chi-square tests with post-hoc residual analyses. Statistical significance was set at P < .05.

Of the 659 patients, 105 (15.9%) had abnormal EMG findings, including 48 (7.3%) with suprascapular neuropathy, 3 (0.5%) with axillary nerve palsy, and 54 (8.2%) with proximal neuropathy. The prevalence of neuropathy increased with tear size and was the highest in the massive tear group, where proximal neuropathy was present in 40.4% of cases. Nerve status was significantly associated with tear size (P < .001), with suprascapular and proximal neuropathy being significantly over-represented in massive tears. Patients with proximal neuropathy were significantly older than those without proximal neuropathy (P = .0001). Shoulder pseudoparalysis occurred in 91 patients (13.8%). Among these, proximal neuropathy was the most common abnormality, identified in 42.9%. The prevalence of pseudoparalysis increased with tear size and was the highest in the massive tear group. A significant association was observed between neuropathy and pseudoparalysis (P < .05).

Neuropathy, particularly proximal neuropathy, was strongly associated with larger RCTs and shoulder pseudoparalysis. These findings suggest that neurological involvement is not incidental but may contribute to disease severity, functional impairment, and the progression of fatty infiltration through the combined effects of disuse and neuropathy. Needle EMG is a valuable tool for detecting neuropathies and may improve diagnostic accuracy and treatment planning. Therefore, EMG should be considered selectively, particularly in patients with large-to-massive tears, severe muscle atrophy, or pseudoparalysis rather than being routinely performed in all cases.