Interrater reliability of clinical examination measures for identification of lumbar segmental instability

Objective: To determine the interrater reliability of common clinical examination procedures proposed to identify patients with lumbar segmental instability. Design: Single group repeated-measures interrater reliability study. Setting: Outpatient physical therapy (PT) clinic and university PT department. Participants: A consecutive sample of 63 subjects (38 women, 25 men; 81% with previous episodes of low back pain [LBP]) with current LBP was examined by 3 pairs of raters. Interventions: Not applicable. Main Outcome Measures: Repeat measurements of clinical signs and tests proposed to identify lumbar segmental instability. Results: Kappa values for the trunk range of motion (ROM) findings varied (range,.00-.69). The prone instability test (kappa=.87) showed greater reliability than the posterior shear test (kappa=.22). The Beighton Ligamentous Laxity Scale (LLS) for generalized ligamentous laxity showed high reliability (intraclass correlation coefficient =.79). Judgments of pain provocation (K range,.25-55) were generally more reliable than judgments of segmental mobility (K range, -.02 to.26) during passive intervertebral motion testing. Conclusions: The results agree with previous studies suggesting that segmental mobility testing is not reliable. The prone instability test, generalized LLS, and aberrant motion with trunk ROM demonstrated higher levels of reliability.