Standardized manual palpation of myofascial trigger points in relation to neck/shoulder pain; the influence of clinical experience on inter-examiner reproducibility

A diagnosis of Myofascial Pain Syndrome (MPS) requires palpation for the identification of at least one clinically relevant trigger point (TP). However, few comparable, high quality studies currently exist from which to draw firm conclusions regarding the robustness of TP examination. An inter-observer agreement study was conducted using two experienced and two inexperienced clinicians. All performed standardized palpation of the upper Trapezius musculature, judging the clinical relevance of TP(s) using clinician global assessment (GA). A random case mix of 81 female participants was examined, 14 asymptomatic and the remainder suffering from neck/shoulder pain. Examiners received psychomotor skills training and video feedback analysis to improve protocol standardization. Kappa co-efficient calculations indicated good agreement between the experienced pairing (κ = 0.63), moderate agreement between the mixed pairings (κ = 0.35 and 0.47) and poor agreement between the inexperienced pairing (κ = 0.22). Inter-observer agreement was not stable with the experienced pairing exhibiting a sharp decline in agreement during the latter portion of the study. Identification of clinically relevant TPs of the upper Trapezius musculature is reproducible when performed by two experienced clinicians, however, a mixed observer pairing can yield acceptable agreement. A protracted period of data collection may be detrimental to inter-observer agreement; more investigation is needed in this regard.