Translation and Cross-cultural Adaptation of the Kerlan-Jobe Orthopaedic Clinic Shoulder and Elbow Score Into Japanese and Comparison of Visual Analog Scale and 10-Point Scale Formats.

Abstract

Background: The Kerlan-Jobe Orthopaedic Clinic shoulder and elbow score (KJOC) is sensitive enough to detect subtle changes in the functional level of the shoulder or elbow in overhead athletes. However, a Japanese version of the KJOC is not yet available. Moreover, the original KJOC uses a visual analog scale (VAS) assessment format that requires a print version so that users can add a check mark along a horizontal line. The KJOC can be completed using online tools such as Google Forms if a 10-point scale format can be used with comparable results.

Purposes: To (1) translate and cross-culturally adapt the KJOC into Japanese (KJOC-J) and assess its validity and (2) evaluate the correlation between a standard VAS format and a 10-point scale format (KJOC-J10).

Study design: Cohort study (Diagnosis); Level of evidence, 3.

Methods: In total, 318 athletes participated in the validation study, 255 in the test-retest reliability study for the KJOC-J, and 273 in the validation study for the KJOC-J10. Internal consistency was evaluated using the Cronbach alpha. Validity was evaluated by calculating the correlation between the KJOC-J and the Disability of the Arm, Shoulder and Hand (DASH). Test-retest reliability was assessed using the intraclass correlation coefficient (ICC). The validity of the KJOC-J10 was evaluated by calculating the correlation between the KJOC-J10 and KJOC-J.

Results: The Cronbach alpha was 0.914, indicating good internal consistency. The KJOC-J was moderately correlated with the DASH (r = -0.581; P < .001) and had good test-retest reliability (ICC, 0.874). A strong correlation was found between the KJOC-J and KJOC-J10 (r = 0.846; P < .001).

Conclusion: The study results demonstrated good internal consistency, validity, and reliability for the KJOC-J, indicating that it is a valid assessment tool for shoulder and elbow functions in Japanese overhead athletes. Moreover, a strong correlation was found between the VAS and 10-point formats of the KJOC-J.