A clinical diagnosis of Myofascial Pain Syndrome (MPS) requires manual palpation for the identification of at least one clinically relevant trigger point (TP). However, few comparable, high quality studies exist regarding the robustness of TP examination. Our aim was to determine the inter-observer agreement of TP examination among four examiners and whether reproducibility is influenced by examiner clinical experience. Two experienced and two inexperienced clinicians each performed a standardized palpation of the upper Trapezius musculature. Each observer was asked to judge the presents/absence of clinically relevant TP(s) using clinician global assessment (GA). A random case mix of 81 female participants was examined, 14 being asymptomatic and the remainder suffering from neck/shoulder pain. Examiners received psychomotor training and video analysis feedback provided prior to and during the study in order to improve protocol standardization. Kappa co-efficients were calculated for all possible examiner pairings. Good agreement was noted between the experienced pairing (κ= 0.63). Moderate levels of agreement were observed among the two mixed pairings (κ=0.35 and 0.47 respectively). However, poor agreement was observed for the inexperienced pairing (κ=0.22). Inter-observer agreement was not stable with the experienced pairing in particular, exhibiting a sharp decline in agreement during the latter portion of the study. Identification of clinically relevant TPs of the upper Trapezius musculature is a reproducible procedure when performed by two experienced clinicians. However, an experienced-inexperienced observer pairing can yield acceptable levels of agreement. A protracted period of data collection may be detrimental to inter-observer agreement.
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The Society for Back Pain Research - Annual General Meeting: The life course of back pain - are we making a difference?, 2010