Photogrammetric Variables Used by Physical Therapists to Detect Neck Pain and to Refer for Physiotherapeutic Intervention: A Cross-Sectional Study

OBJECTIVE: The purpose of this study were as follows (1): to investigate photogrammetry variables that physiotherapists may detect by visually inspecting the static body posture that distinguishes young adults with or without neck pain, which may lead to referral to a physiotherapy intervention, and (2) to assess the reliability of postural assessment and clinical decision-making. METHODS: We conducted a cross-sectional, observational, balanced, controlled, single-blinded study. Fourteen physiotherapists aged 33 (6) years were recruited as raters for postural assessment of adults aged 28 (7) years with (n = 30) or without neck pain (n = 30). Photogrammetry was performed to quantify the static body posture alignments and angles. Visual inspection was performed to indicate the presence of postural misalignment and neck pain and to refer to physiotherapy intervention. RESULTS: Symptomatic participants showed low- to moderate-intensity neck pain, a high frequency of chronic neck pain, and low disability scores. Photogrammetry analysis revealed no statistically significant difference between groups. Classification of the participants according to the raters' visual inspection yielded sets of photogrammetry variables with significant differences, with a large variability among those sets. Intrarater and interrater reliability of photogrammetry varied from moderate to excellent (intraclass correlation coefficient_2,1 = [0.502; 0.995]; intraclass correlation coefficient_2,2 = [0.564; 0.996). Interrater reliability for visual inspection was no better than chance (κ_Light = -0.013 to 0.011; ι = -0.002). CONCLUSION: Neither photogrammetry nor visual inspection distinguished the presence of neck pain in young adults. Using visual inspection, physiotherapists had unreliable clinical decision-making owing to high variability of photogrammetry variables used to distinguish postural misalignments, the presence of neck pain, and whether to refer young adults for physiotherapy intervention.