Reliability of Trigger Point Evaluation in the Lower Leg Muscles

Background: Myofascial trigger point diagnosis is a clinical palpatory skill dependent on the patient's subjective response. The inter- and intra-rater reliability of trigger point physical evaluation in the lower leg muscles has rarely been reported. Previous reliability studies suffered from the Kappa paradox. Objective: To evaluate the inter- and intra-rater reliability of trigger point recognition in the lower leg muscles implying a specific method to overcome the first Kappa paradox. Design: A reliability study with pre-second examiner exclusion to correct prevalence index. Setting: Physical therapy outpatient clinic, Beer-Sheva, Israel. Subjects: In sum, 86 soldiers aged 18-30 referred for physical therapy with a diagnosis of musculoskeletal pain consented to take part in this study; 26 were excluded for lacking trigger points, leaving 60 subjects for analysis (31 women, 29 men). Methods: Both legs were evaluated, and the results were analyzed separately for symptomatic (N = 87) and asymptomatic legs (N = 31). Each subject was evaluated three times, twice by one examiner, and once by a second examiner. Dichotomous findings including palpable taut-band, tenderness, referred pain, and relevance of referred pain were recorded. Results: Inter-rater reliability for active trigger points ranged from 0.49 to 0.75 (median: 0.52) and intra-rater reliability ranged from 0.41 to 0.84 (median: 0.65) and. For total trigger points intra-rater reliability ranged from 0.52 to 0.79 (median: 0.67), and inter-rater reliability ranged from 0.44 to 0.77 (median: 0.66). Conclusions: Physical examination is a reliable method of trigger point evaluation in lower leg muscles, and it can be used as a diagnostic method for trigger point evaluation.