Does bone mineral mass affect medial elbow injuries in young baseball players?: evaluation using bioelectric impedance analysis.

BACKGROUND

Medial elbow injuries occur in approximately one-third of all young baseball players and are characterized by injuries to the bone and cartilaginous growth plates. Bone mineral mass, a representative of bone strength, may show individual differences during growth, and the bone strength can temporarily decrease depending on the stage of bone development. However, the relationship between bone mineral mass and medial elbow injuries in young baseball players has not yet been investigated.

HYPOTHESIS: The bone mineral mass would be lower in players with medial elbow injuries, causing lower bone strength and increased susceptibility to injury.

STUDY

DESIGN

Cross-sectional study.

METHODS

We recruited 215 baseball players aged 9-12 years; the players completed a questionnaire regarding their age, height, weight, practice duration and frequency, baseball experience, and number of pitches per day. The injury and control groups were determined by ultrasonographic evaluation of the medial aspect of the elbow joint, and bone mineral mass was measured by bioelectric impedance analysis. The hip and shoulder ranges of motion were measured. Each variable was compared between the injury and control groups using the Student's t-test. Simultaneous multivariate logistic regression analysis was subsequently performed to identify the factors associated with medial elbow injuries.

RESULTS

Bone mineral mass was significantly higher in the injury group than in the control group (2.02 ± 0.30 kg vs. 1.91 ± 0.26 kg, p = 0.003). However, it was not significantly associated with medial elbow injuries in multivariate logistic analysis. Baseball experience (OR, 1.03; 95% CI, 1.01-1.06; p = 0.009) were significantly associated with medial elbow injury.

CONCLUSION

Contrary to our hypothesis, bone mineral mass was higher in players with medial elbow injuries, but was not significantly associated with them. A one-time measurement of bone mineral mass is probably not specific enough to analyze the condition of the medial epicondyle. Baseball experience has been identified as a possible factor associated with medial elbow injuries in young players, and increases in experience should be used as an indicator to assess elbow joint health.