Now, researchers hope high-resolution ultrasound will help detect abnormalities in pitchers' elbow ligaments before pain starts -- or possible career-ending injuries occur.
Ultrasound -- based on the technology that lets doctors see a baby in the womb -- provides a clear view of the wear and tear on a pitcher's elbow before it's too late, say researchers at Jefferson Medical College at Thomas Jefferson University in Philadelphia.
"Usually there's no pain until injury happens," says Dr. John M. McShane, a co-author of the study and team physician for the Philadelphia Phillies. "With this injury, it's an all-or-nothing thing: They'll have no pain --then 'pop' -- and that's it."
The study, in the April issue of Radiology, focused on the ulnar-collateral ligament (UCL), which connects the humerus bone in the upper arm to the ulna bone in the forearm.
Magnetic-resonance imaging (MRI), typically used after symptoms of UCL injury appear, can detect acute ruptures, but ultrasound quickly picks up smaller tears and signs of chronic injury, the researchers say.
Ultrasound tests of 26 major league pitchers during spring training 2001 showed much more UCL degeneration in their throwing arms than their other arms, and wear and tear proved worst among those who had pitched the most years, the study found.
In the pitching arms, the UCL's anterior band, largely responsible for providing stability in the elbow joint, had grown thicker than the anterior band in the other arm, reflecting a loss of elasticity.
Ultrasound also revealed micro-tears, which ultimately can lead to a larger tear that requires surgery, in the UCL in 18 of the 26 pitching arms, compared with three of the non-pitching arms. Calcification, which often accompanies ligament injuries, appeared in nine of the 26 throwing arms, but none of the other arms.
Precisely which early signs predict later injury remains a mystery, however, McShane says. The ongoing study aims to solve the puzzle.
By following pitchers year to year, the researchers hope that when UCL injuries happen, they'll be able to look back at abnormalities to find which early signs could predict the injuries.
Then perhaps injuries could be prevented, the researchers say, through rehabilitation or changing the mechanics of pitching -- for example, by relying more on the shoulder, hips and other parts of the body to reduce stress on the elbow.
The Jefferson researchers have increased the number of pitchers they're following, to about 100 during spring training this year, but have reported results on only the first 26.
Compared with MRI, ultrasound detects more UCL abnormalities in part because the arm can be stressed during ultrasound, simulating stress of the pitching motion. During the more costly MRI, the pitcher must keep his arm still for 20 to 25 minutes, McShane says, while the ultrasound takes less than five minutes.
"It's so easy to use it, not only after injury, but as a screening tool," McShane says. "We can put the ultrasound scanner directly on the elbow and literally within a minute or two have an answer."
Dr. John Reilly, team physician for the minor league Staten Island Yankees, says he's still more confident in the MRI, the "gold standard" for assessing UCL injuries. Based solely on ultrasound results, Reilly says, "I don't know if I'd make a judgment" on whether to allow a pitcher to play.
But Reilly, an orthopedic surgeon at Staten Island University Hospital, says ultrasound could help rule out abnormalities in some players. And, if further testing proves ultrasound picks up warning signs of UCL injuries, it could become a useful tool, he says.
"If you could come to the point where you rely solely on the ultrasound," Reilly says, "then you got something. It would certainly behoove us to pick up on the problem sooner."
For more on UCL injuries, visit the Johns Hopkins Department of Orthopaedic Surgery. To learn more about the connection between pitching mechanics and elbow injuries (even among children), read this article from the American Physical Therapy Association.