Doctors at Columbia University in New York City report a rare case of avulsion fracture of the lesser tuberosity in a 15-year-old baseball pitcher. An avulsion fracture occurs when the tendon tears away from the bone with a small piece of bone attached to it.
The lesser tuberosity is a bump on the front of the upper arm bone. The tendon of the
subscapularis muscle attaches to this bump. The subscapularis is the muscle that helps rotate the shoulder inward while pitching the ball forward. The injury occurs when the arm is rotated back to an extreme position for the pitch.
Rare injuries of this type are becoming more common in children’s sports. Repeated throwing in extreme shoulder positions is the most likely cause. In this case the boy reported sudden shoulder pain during a pitch. He was unable to keep pitching. Ten weeks later he still couldn’t pitch.
Exam and X-ray pointed to an avulsion injury. Treatment was rest and then physical therapy (PT). PT was used to restore motion, reduce inflammation, and increase strength. This pitcher returned to full sports participation 19 weeks later. He was still pitching pain free a year later.
The authors of this report compare Little Leaguer’s shoulder to an avulsion injury of this type. They discuss the mechanism of both injuries. Risk factors in young athletes are also reviewed. Surgery may be needed for either injury if healing doesn’t occur in six to 10 weeks.