Objective: To investigate intra- and inter-observer reliability among physical medicine and rehabilitation specialists and a radiologist in interpretation of plain lumbar spine X-ray films in patients with low back pain.
Methods: Three assessors (A: a resident of PM&R, B: an experienced PM&R specialist, C: an experienced radiologist) read the standard lumbosacral plain radiographs of 79 patients with 2-3 month time interval. Each assessor recorded the presence or absence of abnormalities on the radiograph according to a standardized assessment form.
Results: For assessors B and C, all kappa values were > 0.40. Transitional vertebrae abnormalities reached to the highest agreement ratio. The intrarater agreement showed higher kappas than the interrater agreement. The radiologists had the highest intrarater agreement, closely followed by the experienced PM&R specialist. Agreement among three assessors was substantial in sacralisation, lumbarisation and facet joint pathologies.
Conclusion: We usually obtained a good intrarater agreement, especially for the experienced PM&R specialist and the radiologist indicating that experience increases diagnostic consistency. Besides the systematic differences in radiographic interpretation between the assessors, institutional specific conditions (esp. patient profile and regularities) may cause the phycians to pay more attention to a specific group of pathologies.