Development of the Italian version of the modified Japanese orthopaedic association score (mJOA-IT): cross-cultural adaptation, reliability, validity and responsiveness

PURPOSE: The modified Japanese orthopaedic association scale (mJOA) is considered one of the most appropriate outcome measures for the assessment of cervical spondylotic myelopathy (CSM). Moreover, mJOA has been recognised among the key predictors of surgical outcome at a global level. To apply the mJOA successfully at an international level, it should be translated and culturally adapted in the native language of the investigators using this scale. A translated version of the mJOA or any other functional scale has never been studied within an Italian population affected by CSM. The aim of this study has been to describe translation, cultural adaptation and psychometric properties of the Italian version of the mJOA (mJOA-IT).METHODS: The mJOA-IT was developed following a forward-backward translation procedure. Psychometric properties were assessed on a cohort of patients with CSM undergone anterior or posterior decompression associated with stabilisation in lordosis.RESULTS: The mJOA-IT proved to be a reliable outcome measure for CSM (internal consistency 0.60, test-retest stability 0.910, P < 0.001, inter-observer reliability 0.80, P < 0.001). The mJOA-IT was associated with the Nurick scale (r = -0.615) while it was not associated with NDI, SF-36 and SF-36 components. The mJOA-IT was also responsive (d = 0.867).CONCLUSIONS: The mJOA-IT proved to be a reliable and valid tool to assess patients affected by CSM. This form is recommended to be used for clinical and research purposes in Italy, to promote the global standardisation of assessment tools and to compare studies on CSM worldwide.