The Overlapping Roles of Neuropathic and Nociplastic Pain in Non-Traumatic Shoulder Disorders: Implications for Pain Mechanisms and Disability

Background
Non-traumatic shoulder pain is a prevalent musculoskeletal condition that impacts daily activities, work productivity, and quality of life. While traditionally considered nociceptive, recent evidence suggests neuropathic and nociplastic mechanisms may also play a role. However, their interaction and impact on functional impairment remain unclear.
Aims
This study aimed to assess the prevalence of neuropathic pain, its association with nociplastic pain, and their effects on functional disability.
Methods
This multicenter, cross-sectional study included 73 patients with non-traumatic shoulder pain persisting for over three months. Participants were classified based on rotator cuff disorders, subacromial impingement, adhesive capsulitis, osteoarthritis, or calcific tendinitis. Pain intensity (VAS), neuropathic pain (S-LANSS), central sensitization (CSI), and functional impairment (SPADI) were assessed, and correlations were analyzed.
Results
Neuropathic pain was present in 26% of patients, while 28.8% exhibited central sensitization, indicating nociplastic pain. Patients with both neuropathic and nociplastic pain had significantly higher SPADI scores (p < 0.05), reflecting greater functional impairment. However, nociplastic pain alone was not significantly associated with disability. Patients with central sensitization had higher VAS scores and longer symptom duration (p < 0.05), suggesting its role in pain chronicity.
Conclusion
Neuropathic and nociplastic pain mechanisms overlap in non-traumatic shoulder disorders but have distinct clinical implications. Nociplastic pain contributes to pain perception, whereas neuropathic pain is more strongly linked to functional impairment. These findings underscore the need for multidisciplinary treatment strategies addressing both pain components rather than focusing solely on central sensitization.