A whole bunch of Little League baseball players teamed up for this study. All 343 ball players had taken part in the regional and national championships in Taiwan. Most were pitchers, but catchers and fielders were also included. They ranged in age from 9.5 to 12 years. The goal was to find rates of elbow injury and see what shows up on an X-ray.
Players were asked about hand dominance, years of playing, number of throws, and hours of practice each day and week. They also reported any painful or sore symptoms during or after pitching or throwing practice. A doctor examined each player’s elbows. The angle of each elbow was measured and compared. X-rays of each elbow were taken. Thickness of the bone was recorded for both arms (throwing and nonthrowing arms).
Almost all the players had increased bone density at the elbow of the throwing arm. Pitchers had the greatest amount of change in this area compared to fielders and catchers. Catchers were more likely to have soreness and elbow deformity than pitchers or fielders. More than half of all the boys had a space greater than 1 mm between the growing bone and the main bone on the inside of the arm. Only half of these players had any pain or soreness.
The authors think changes seen on X-ray are caused by chronic traction stress on the inside of the elbow. The changes in the bone may not have anything to do with the player’s symptoms. This finding needs more study before any links are known for sure.