Shoulder pain phenotyping: A guide for clinicians to determine predominant nociceptive, neuropathic, or nociplastic shoulder pain.

Background Persistent shoulder pain is common, and it is associated with substantial morbidity and healthcare costs. Approximately 21 to 50 % of people with shoulder pain treated in primary healthcare recover within six months. It is not known why at least half do not recover. One possibility is the manner underlying mechanisms related to persistent shoulder pain are managed. Being able to determine the predominant pain phenotype in people with persistent shoulder pain (i.e., nociceptive, neuropathic, or nociplastic pain) together with their underlying mechanism and tailoring management accordingly may improve outcomes for people seeking care for persistent shoulder pain. The International Association for the Study of Pain (IASP) recently developed clinical criteria and a grading system for the identification of nociplastic pain. Objective In this paper, we aim to provide suggestions to clinicians to assist in the evaluation of pain phenotypes, underlying mechanisms, and their causal relationships. Discussion Based on the IASP clinical criteria and grading system for nociplastic pain, we outline pain phenotype evaluation and provide a clinical reasoning framework. To facilitate this, three case studies involving people living with persistent shoulder pain are presented.