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LAS VEGAS -- Baseball pitchers looking for more heat should not expect help from ulnar collateral ligament (UCL) reconstruction, better known as , researchers reported here.

Average fastball pitch speed was about the same relative to pre-procedural statistics, and pitchers tended to throw fewer fastballs than before, according to Oliver Sax, DO, of Sinai Hospital of Baltimore, and colleagues.

In addition, pitchers' control appeared to suffer, the researchers reported from their study of 174 major league pitchers, with 3.9 walks issued per 9 innings pitched after surgery, compared with 3.5 previously (P<0.05).

Findings from the study were reported at the American Academy of Orthopaedic Surgeons' annual meeting.

One of the few surgical procedures named after its rather than the physician who developed it, Tommy John surgery involves replacing, or augmenting, the UCL with connective tissue taken from elsewhere in the patient's body. Pitchers' throwing motions put tremendous strain on the UCL, particularly when they repeatedly throw as hard as they can. A fastball specialist might throw as many as 60 or 70 in a single game. As a result, UCL tears are common. These were essentially career-ending until , pioneered the procedure in 1974, helping Tommy John pitch effectively for another 14 years.

Sax and colleagues, however, pointed out that some people in the sport have suggested that UCL reconstruction could even be performed in healthy players to improve their performance -- despite "inconsistent" results from past studies of outcomes.

Thanks to baseball's obsessive collection of statistics, the group was able to analyze a range of outcomes in 174 major league pitchers who underwent UCL reconstruction from 1997 to 2020. Pitchers' mean age was 26 at the time of surgery.

Pre- and post-procedural performance measures, in addition to walks per 9 innings, were as follows:

• Fastball percentage of pitches thrown: 61.2% pre vs 55.0% post, P<0.001

• Mean fastball velocity in mph: 92.3 pre vs 91.5 post, P=0.195

• Earned run average: 4.2 pre vs 4.4 post, P=0.316

• Walks plus hits per inning: 1.4 pre and post

• Strikeouts per 9 innings: 8.1 pre vs 8.3 post, P=0.377

• : 6.8 pre vs 3.9 post, P=0.003

This last finding is especially telling, as it's a measure of how an individual pitcher stacks up against league averages -- it's supposed to indicate how many more wins the team achieved with this pitcher versus a hypothetical replacement. It combines a variety of different statistical measures such as innings pitched per game, walks and runs given up, and others. The reduction by nearly half after UCL reconstruction suggests that pitchers generally did not return to their previous form.

It's possible, though, that this reflects players' aging, as post-surgical rehabilitation typically takes more than a year. Among 276 major league pitchers undergoing surgery from 1974 to 2020 (including the 174 with complete performance outcomes), Sax and colleagues found a mean lapse of 19 months for their return to the major league level. At least anecdotally, it's common to need additional time to "shake off the rust" after long absences from competition, such that it could be 3 years after surgery for players to reach maximum performance.

Overall, the researchers concluded, their results are "contrary" to those suggesting that pitchers could actually improve their fastballs with UCL reconstruction.

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