Agreement of clinical examination for low back pain with facet joint origin.

Background: Low back pain (LBP) with facet joint origin is a common diagnosis of patients referred to physical therapy clinic. An expert consensus of diagnostic criteria has been proposed. However, the reliability of the assessment has not been proved.

Objective: To test the degrees of agreement between two physical therapists for nine physical examination items and the diagnosis of facet joint origin.

Methods: The examination according to diagnostic criteria was performed independently by two physical therapists in 45 patients with chronic LBP. The percent agreements and Kappa coefficients of each examination item and diagnostic conclusion were calculated.

Results: The percent agreements of nine examined items ranged from 73.3-91.1%. The Kappa coefficients, widely ranged from 0.250-0.690 ( $p=0.48$ to $<0.001$ ), showed statistically significant agreements for all examination items. The low level of agreements was partly due to improper distributions of test results. The agreement of conclusion was 86.7% and Kappa coefficient was 0.492 ( $p=0.001$ ) which reflected good agreement of facet diagnosis.

Conclusion: There were adequate agreements for clinical examination of LBP with facet joint origin. The low level of agreement suggested the clinicians to have operational definition and rigorous training sessions although the examinations seemed to be routinely performed.