Injuries to the ulnar collateral ligament (UCL) of the elbow are common in Major League Baseball. That ligament is the main stabilizer to some of the forces on the elbow with the throwing motion. With repeated stress over time, that ligament can fray and ultimately fail. Reconstruction of the ulnar collateral ligament, better known as Tommy John surgery, is usually required to allow an elite pitcher to return to the mound.

While success rates for return to pitching after UCL reconstruction usually exceed 80%, little is known about how the injury and surgery affect pitching performance.

New study of pitching performance after Tommy John surgery

Researchers at Henry Ford Hospital in Detroit, Michigan looked at the pitching performance data for 168 MLB pitchers who had undergone UCL reconstruction. Specifically they analyzed the earned run average (ERA), walks and hits per inning pitched (WHIP), winning percentage, and innings pitched. They looked at that data over the 3 years prior to surgery and the 3 years after surgery and also compared them to the data for 168 age-matched, uninjured MLB pitchers.

They presented their findings recently at the American Orthopaedic Society for Sports Medicine’s Annual Meeting.

Among the pitchers who underwent UCL reconstruction, pitching performance declined after surgery compared to their pre-surgery performance. ERA, WHIP, and the number of innings pitched all dropped.

Possibly more surprisingly, the researchers found a downward trend in pitching performance in the year prior to UCL injury. In the year before surgery, the pitchers’ ERA, WHIP, innings pitched and wining percentage were all significantly worse than the prior two seasons.

Also read:
What is causing the spike in Tommy John injuries?
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Performance differs between injured and non-injured pitchers

The researchers found differences between the injured pitchers and non-injured pitchers as well. 60% of the pitchers in this study required surgery within their first 5 years in the major leagues. Likewise, the surgically treated pitchers had pitched more major league innings at three years and two years before surgery than did the non-injured pitchers. The reconstructed pitchers also had more years of MLB pitching when compared to age-matched non-injured pitchers. The authors concluded that pitchers who begin pitching at the major league level at a younger age have a higher risk for ultimately needing UCL reconstruction surgery.

“Our results suggest that UCL reconstructive surgery does a tremendous job in allowing players to return to their same level of sport but it also describes a decline in pitching performance after undergoing reconstruction. We also found that there is a statistically significant decline in pitching performance the year before reconstructive surgery and this decline was found to be a risk factor for requiring surgery. Our study further noted an increased risk of players requiring surgery if they enter the Major Leagues at a younger age,” said lead author Robert A. Keller, MD.

Also read:
The misperceptions of Tommy John surgery
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Risk factors for ulnar collateral ligament (UCL) injury

UCL injuries are largely believed to be overuse injuries over many years of pitching. The increasing incidence of Tommy John surgeries performed on high school pitchers suggests that overuse starting at younger ages could play a role in these injuries later in players’ baseball careers. More and more pitchers start pitching year round as early as age 7 or 8. In addition, showcase events encourage the top athletes to pitch on weekends throughout the year despite arm fatigue.

This study suggest that we might pay attention to more than just the number of pitches and innings thrown through a pitcher’s career. These data suggest that we should be suspicious of an ulnar collateral ligament injury if a pitcher’s performance starts to suffer, especially if he is noticing medial elbow pain.

Take home message?

“Having athletic trainers and team physicians, closely look at when players pitching performance stats start to decrease may allow for steps to be taken with a pitcher before a surgery is needed. Our study also further highlights the need for kids not to overuse their arms early in their pitching careers,” concluded Keller.