Cross-cultural adaptation, validity and reliability of the Korean version of the Kerlan-Jobe Orthopedic Clinic shoulder and elbow score Joo Han Oh, MD, PhD a , Joon Yub Kim, MD, PhD b, *, Orr Limpisvasti, MD c , Thay Q. Lee, PhD d,e , Seong Hun Song, MD b , Ki Bum Kwon, MD b a Department of Orthopedic Surgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Gyeonggi-do, Republic of Korea b Department of Orthopedic Surgery, Myongji Hospital, Seonam University College of Medicine, Goyang, Gyeonggi-do, Republic of Korea c Kerlan-Jobe Orthopaedic Clinic, Los Angeles, CA, USA d Orthopaedic Biomechanics Laboratory, Long Beach Veterans Affairs Healthcare System, Long Beach, CA, USA e Department of Orthopaedic Surgery, University of California, Irvine, CA, USA ARTICLE INFO Keywords: Overhead Athlete Shoulder Elbow Adaptation Validity Reliability Korean Level of evidence: Basic Science Study, Development or Validation of Outcomes Instruments Background: The Kerlan-Jobe Orthopedic Clinic shoulder and elbow score (KJOC score) was developed for assessing performance and function in overhead athletes with shoulder and elbow injury and recently adapted as the standard score for overhead athletes in Major League Baseball. However, the Korean version of the KJOC score was not developed in the literature. The aim of the current study was to adapt the English version of the KJOC score to develop a Korean version (K-KJOC) and to evaluate its validity and reliability. Methods: A total of 52 professional baseball players in the Korean Baseball League completed the K-KJOC at two-week intervals during the off-season. The QuickDASH (11-point Disabilities of the Arm, Shoulder and Hand) score was also performed to evaluate the construct validity of the K-KJOC score. The internal consistency of reliability and test–retest reliability were assessed as well. Results: The K-KJOC score was correlated with the Quick DASH – disability/symptom (-0.309, ~-0.268, p < 0.05), Quick DASH – work (r =-0.721 to -0.671, p = 0.000) and QuickDASH – sports (r =-0.721 to -0.714, p = 0.000). The internal consistency of the K-KJOC score was excellent (Cronbach’s α: 0.917–0.966), and the intra-class correlation coefficients of test–retest reliability for the 10 items for the K-KJOC score were fair to excellent (ICC 0.505–0.937, p < 0.05). Conclusion: The K-KJOC score appeared to be a valid and reliable tool for assessing shoulder and elbow injuries in Korean overhead athletes. © 2017 The Authors. Published by Elsevier Inc. on behalf of American Shoulder and Elbow Surgeons. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by- nc-nd/4.0/). Sports-specific instruments for evaluation of performance as well as functional status of overhead athletes are limited and the tra- ditional evaluation for recovery from previous musculoskeletal injuries has been described with the term ‘return to play’. 1,8 The development of instruments to detect the subtle change of sports-related functions in athletes 1,8 might be more difficult than the development of functional outcome instruments in the average population due to the limited knowledge of sports and athletes. Therefore, the commonly used functional outcome instruments in specific diseases, such as the ASES (American Shoulder and Elbow Society) form, the Mayo elbow performance score, and DASH (Dis- abilities of Arm, Shoulder and Hand), have been used for the functional evaluation of overhead athletes up to date. 18 The other well-known previous functional evaluation tools for overhead ath- letes were return-to-sport rate, the Conway–Jobe score and the Timmerman–Andrews score. 3,5,18,19,24,25 The Conway–Jobe score was used to assess outcomes in throwing athletes after ulnar collater- al ligament (UCL) repair or reconstruction 3,5,24 and the Timmerman– Andrews elbow score was developed to evaluate post-traumatic The Institutional Review Board of Myongji Hospital approved this study: No. MJH-16-106. These authors, their immediate family, and any research foundation with which they are affiliated did not receive any financial payments or other benefits from any commercial entity related to the subject of this article. No benefits in any form have been received or will be received from a commercial party related directly or indi- rectly to the subject of this article. * Corresponding author. Joon Yub Kim, MD, PhD, Department of Orthopedic Surgery Myongji Hospital, Seonam University College of Medicine, 55, Hwasu-ro 14beon-gil, Deokyang-gu, Goyang, Gyeonggi-do, Republic of Korea. E-mail address: doctoryub@naver.com (J.Y. Kim). http://dx.doi.org/10.1016/j.jses.2017.03.001 2468-6026/© 2017 The Authors. Published by Elsevier Inc. on behalf of American Shoulder and Elbow Surgeons. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). JSES Open Access 1 (2017) 39–44 Contents lists available at ScienceDirect JSES Open Access journal homepage: www.elsevier.com/locate/jses