An outcome measure of functionality and pain in patients with lumbar disc herniation: a validation study of the Japanese Orthopedic Association (JOA) score

Lumbar disc hernia (LDH) is a common cause of low back pain and radicular leg pain. The Japanese Orthopedic Association (JOA) score is a very short instrument for measuring functionality and pain in these patients. This study aimed to translate and validate the JOA score for use in Iran. This was a prospective clinical validation study. Translation of the English version of the questionnaire was performed in accordance with published guidelines. A sample of patients with LDH was asked to respond to the questionnaire at two points in time-at preoperative and postoperative (6 months follow-up) assessments. To test reliability, the internal consistency was assessed by use of Cronbach's alpha coefficient. Validity was evaluated by use of known-groups comparison. A total of 117 patients with LDH were entered into the study. The mean age of patients was 45 (SD = 11) and Cronbach's alpha coefficients for the JOA score at the preoperative and postoperative assessments were 0.67 and 0.81, respectively. Validity as performed by known-groups analysis also showed the result was satisfactory. The instrument discriminated well between sub-groups of patients who differed in age and in a standard predictive measure of lumbar disc surgery (the Finneson-Cooper score). In general, the Iranian version of the JOA score performed well and the findings suggest that it is a reliable and valid measure of functionality and pain among LDH patients.