Development and validation of the Korean version of the Modified Japanese Orthopedic Association Score: a prospective questionnaire study.

Abstract

A prospective questionnaire-based study. This study aimed to translate, adapt, and validate the Korean version of the modified Japanese Orthopedic Association (mJOA) score. The mJOA score is considered one of the most commonly used instruments for assessing the functional status of patients with cervical myelopathy. However, a Korean version of the mJOA score has not yet been developed, limiting its standardized assessment in Korean-speaking populations. This prospective, questionnaire-based study adhered to established cross-cultural adaptation guidelines to translate the mJOA score into Korean. One hundred and twenty-two native Korean-speaking patients with cervical myelopathy recruited from a spine outpatient clinic were administered the final version. Test-retest reliability and internal consistency were assessed using the intraclass correlation coefficient (ICC) and Cronbach's alpha. Item-level analyses included the mean, standard deviation, and floor and ceiling effects. Construct validity was assessed by analyzing the correlations between the Korean mJOA scores and other patient-reported outcome measures, including the Visual Analog Scale (VAS) and the adapted Korean version of the Neck Disability Index (AK-NDI). This study investigated a total of 122 patients with cervical myelopathy (74 men and 48 women; mean age, 62.5±11.5 years) who completed the Korean mJOA. Internal consistency was acceptable (Cronbach's α=0.666), and test-retest reliability was moderate to excellent across most domains (ICC=0.478-0.896). The total mJOA score also showed a moderate negative correlation with the AK-NDI (r =-0.497, p <0.001) and a weak negative correlation with the arm pain VAS (r =-0.339, p =0.003). This study successfully developed and validated the Korean version of the mJOA score, making it a reliable tool for assessing functional impairment in Korean-speaking patients with cervical myelopathy. Its clinical and research use could standardize patient assessments and improve the management of cervical myelopathy in Korea.