Clinical Utility of the Japanese Version of the Kerlan-Jobe Orthopaedic Clinic Shoulder and Elbow Score for Detecting...

Upper extremity injuries are prevalent among high school baseball players, many of whom continue playing despite mild or early symptoms. Although the Kerlan-Jobe Orthopaedic Clinic Shoulder and Elbow Score (KJOC) is a validated patient-reported outcome (PRO) for overhead athletes, its sensitivity in identifying early dysfunction in field-active adolescent athletes remains unclear.

This study aimed to determine the clinical utility of the Japanese version of the KJOC (J-KJOC) for identifying symptomatic high school baseball players and to establish a cutoff score for the early detection of upper extremity dysfunction.

Cross-sectional study.

A total of 86 high school male baseball players were categorized into three groups based on their self-reported J-KJOC: asymptomatic, symptomatic but active, and inactive symptomatic. All participants underwent physical assessments, including shoulder range of motion, isometric shoulder strength, grip strength, and pinch strength measurements. Between-group comparisons, receiver operating characteristic (ROC) analysis, and logistic regression were conducted to determine the discriminative performance of the J-KJOC and its association with physical assessments.

The mean age of the participants was 16.3 ± 0.8 years. The J-KJOC scores differed significantly among the three groups (p < 0.01), whereas no significant differences were found in the physical assessments. The ROC analysis revealed a J-KJOC cutoff score of 87.6 with an area under the curve (AUC) of 0.815, yielding 81.5% sensitivity and 72.8% specificity for distinguishing symptomatic players. Logistic regression analysis revealed that only the J-KJOC score, and not conventional physical parameters, was significantly associated with symptoms while playing, across all models.

The J-KJOC demonstrated superior sensitivity to conventional physical assessments in detecting upper extremity dysfunction in high school baseball players. A cutoff score of 87.6 may serve as a valuable screening threshold for early intervention and injury prevention in high school baseball athletes.

Level 3.