Reliability and Validity of the Thai Version of the Modified Japanese Orthopaedic Association Score (mJOA score)

Objective: To evaluate the reliability and validity of the Thai version of the modified Japanese Orthopaedic Association scale. Methods: The modified Japanese Orthopaedic Association scale was translated into Thai language to create the Thai version of the Modified Japanese Orthopaedic Association (Thai-mJOA) scale. Translation was performed according to international standards using a forward-backward translation protocol. Translation was performed by 2 expert translators and 1 physician, and the final version was approved by an expert committee. Thai patients with cervical spondylosis with myelopathy were enrolled and evaluated using the Thai-mJOA scale, Nurick Grading, the Thai version of the Neck Disability Index (Thai-NDI), and the Thai version of the Short Form-36 (Thai-SF-36). Reliability and validity of the Thai-mJOA were assessed via comparison with the Nurick Grading and the Thai-NDI. Results: Ninety-two patients were included. The most common compression level was C5-C6 vertebral disc. Cronbach’s alpha of the total Thai-mJOA showed excellent internal consistency (0.991). The intraclass correlation coefficient (ICC) for test-retest reliability was 0.981 (95% confidence interval [CI]: 0.972-0.988). Regarding concurrent validity, the motor dysfunction score of the lower extremities and the total score of the Thai-mJOA were strongly correlated with Nurick Grading (r=0.825, r=0.712, respectively). The total score of the Thai-mJOA was moderately correlated with the Thai-NDI (r=0.670). Conclusion: The Thai-mJOA was found to be a valid and reliable tool for evaluating symptom severity in Thai patients with cervical spondylosis with myelopathy