Poster 187: The Effect of Elbow Varus Torque on Medial Epicondyle in Little League Pitchers

OBJECTIVES: In baseball players, elbow varus torque is associated with the risk of medial elbow injuries. However, the effect of elbow varus torque on medial epicondyle deformity among youth baseball players has not yet been clarified. To clarify the relationship between elbow varus torque and medial epicondyle abnormality in little league pitchers. METHODS: The participants consisted of 173 little league pitchers (mean age, 10.6±0.6 years; range, 10-12 years). The pitchers were instructed to throw a ball into a netting target at maximum effort three times. A sensor placed at the medial elbow reported elbow torque, arm speed, arm slot, and shoulder rotation for each pitch, while a radar gun measured peak ball velocity. The medial epicondyle of each player was evaluated using ultrasound imaging (Figure 1). A questionnaire was used to investigate the background (age, height, weight) and the past or present elbow pain. The average of elbow varus torque was calculated. Players were divided into high-torque group and low-torque group depending on whether the torque is higher or lower than average elbow varus torque. The relationship between elbow varus torque and the presence of ultrasound abnormality and elbow symptom was statistically analyzed among two groups. RESULTS: A medial epicondyle deformity was observed in 85 players (49%). The results of this study showed that height (146.8±6.6 cm vs. 138.9±5.9 cm), weight (39.5±7.1 kg vs. 32.4±4.8 kg), and ball velocity (72.7±7.5 km/h vs. 67.6±6.8 km/h) were significantly higher in the high torque group than in the lower torque group (P<.001), while arm slot (48.6±12.4 degrees vs. 54.9±14.4 degrees) was significantly lower in the high torque group (P<.05) (Table 1). The rate of players who experienced past elbow pain was significantly higher in the high-velocity group (P<.05), while there were no significant differences in the rate of present pain among the two groups (Table 2). The rate of medial epicondyle abnormality was significantly higher in the high-torque group than in the low-torque group (chi-square test; P<.05) (Figure 2). CONCLUSIONS: In this study, a medial epicondyle deformity and past elbow pain were significantly higher in the high torque group. High elbow varus torque would increase the risk of medial elbow disorder.