Comparison of the Japanese Orthopaedic Association (JOA) score and modified JOA (mJOA) score for the assessment of cervical myelopathy: a multicenter observational study.

So Kato,Junichi Kunogi,Hiroyuki Oka,Rentaro Okazaki,Katsushi Takeshita,Yasushi Oshima,Michael Fehlings,Sakae Tanaka,Hirotaka Chikuda,Naohiro Kawamura,Yujiro Takeshita,Kazuhiro Masuda,Seiichi Azuma,Nobuhiro Hara,Kota Miyoshi

doi:10.1371/journal.pone.0123022

Abstract

ObjectivesThe Japanese Orthopaedic Association (JOA) score is widely used to assess the severity of clinical symptoms in patients with cervical compressive myelopathy, particularly in East Asian countries. In contrast, modified versions of the JOA score are currently accepted as the standard tool for assessment in Western countries. The objective of the present study is to compare these scales and clarify their differences and interchangeability and verify their validity by comparing them to other outcome measures.Materials and MethodsFive institutions participated in this prospective multicenter observational study. The JOA and modified JOA (mJOA) proposed by Benzel were recorded preoperatively and at three months postoperatively in patients with cervical compressive myelopathy who underwent decompression surgery. Patient reported outcome (PRO) measures, including Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire (JOACMEQ), the Short Form-12 (SF-12) and the Neck Disability Index (NDI), were also recorded. The preoperative JOA score and mJOA score were compared to each other and the PRO values. A Bland-Altman analysis was performed to investigate their limits of agreement.ResultsA total of ninety-two patients were included. The correlation coefficient (Spearman’s rho) between the JOA and mJOA was 0.87. In contrast, the correlations between JOA/mJOA and the other PRO values were moderate (|rho| = 0.03 – 0.51). The correlation coefficient of the recovery rate between the JOA and mJOA was 0.75. The Bland-Altman analyses showed that limits of agreement were 3.6 to -1.2 for the total score, and 55.1% to -68.8% for the recovery rates.ConclusionsIn the present study, the JOA score and the mJOA score showed good correlation with each other in terms of their total scores and recovery rates. Previous studies using the JOA can be interpreted based on the mJOA; however it is not ideal to use them interchangeably. The validity of both scores was demonstrated by comparing these values to the PRO values.

Highlights

Cervical compressive myelopathy is a common disorder that frequently results in impairment of a patient’s motor, sensory and bladder function
The Bland-Altman analyses showed that limits of agreement were 3.6 to -1.2 for the total score, and 55.1% to -68.8% for the recovery rates
Previous studies using the Japanese Orthopaedic Association (JOA) can be interpreted based on the modified JOA (mJOA); it is not ideal to use them interchangeably

Summary

Introduction

Cervical compressive myelopathy is a common disorder that frequently results in impairment of a patient’s motor, sensory and bladder function. Several scales that measure severity of physical disability have been developed to assess a patient’s pre- and post-treatment condition and the effectiveness of intervention. The Japanese Orthopaedic Association (JOA) score was developed by the JOA in 1975. Since it has become one of the most frequently used outcome measures to evaluate functional status in patients with cervical myelopathy. The revised version of the JOA score (1994), which includes an assessment of the shoulder and elbow function, is the most frequently used [2, 3]

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