There are a few things that I really enjoy doing. One of those things is watching baseball and researching baseball. As any baseball fan can tell you, one huge issue that as been facing Major League Baseball players recently is the increase in Tommy John surgery for professional pitchers. For those who do not know what a “Tommy John” surgery consists of, it is a surgery used to replace a pitcher’s UCL or ulnar collateral ligament. The surgery was created originally in 1974 for pitcher “Tommy John” hence the name. The tearing of a pitcher’s UCL has become more and more prevalent in the MLB as of late. The question I would like to answer: What are the factors responsible for this recent uptick in Tommy John surgeries?
The first thing you have to look at when examining this question is: What usually causes ligaments in the arm to tear? As per Dr. Ken Fleisig, he cites torque on the elbow as the reason for tearing ligaments in the arm, especially the UCL. Now obviously professional pitchers put an incredible amount of torque on the elbow as they are throwing the ball anywhere from 90-100 mph. This torque is so great that hypothetically, any given pitcher’s UCL should tear on every pitch. Fleisig states that a typical pitch puts 100 newton meters of force on the elbow. About half of this force is placed on the UCL. That puts around 50-55 newton metres of force on the elbow. In tests on cadavers, it has shown that a typical UCL can not withstand more than 32 metres of force. Obviously the ligaments of cadavers are not at the same strength as professional baseball players, this however does not make up for the huge discrepancy as to what your UCL should be able to withstand and what professional pitchers are making it withstand. So for pitchers we are able to see a strong correlation between torque placed on the elbow and the likelihood of tearing one’s UCL. Our next question would be to ask: What causes an increase in torque on the elbow? Increased torque on the elbow can be seen by an increase in arm speed and the use of a curveball. The use of a curveball becomes especially dangerous in younger arms as many young baseball players ligaments and joints are not fully developed and can not withstand this incredible amount of torque placed on their UCL. (Flesig)
Now that we see the causes for UCL injuries, the next question that would need to be answered is: Why are we seeing more UCL injuries now? One possible explanation could be that simply pitchers are throwing harder now than they used to. Research done by FanGraphs‘ Julien Assouline, would suggest that an increase in velocity does seem to increase the likelihood of Tommy John surgery. After looking at average velocity thrown by a pitcher and comparing it to if they had Tommy John surgery or not, Assouline was able to conclude that a pitcher who throws 90 mph is 7-10% less likely to have Tommy John than a pitcher who throws 96 mph. It appears that velocity is a factor, what else could be a looming factor in this recent Tommy John epidemic? Many would suggest that the overuse of little league pitchers. While pitching any young baseball player too much will have an obvious impact on his arm, this does not necessarily equate to a higher risk of Tommy John. The main study people like to point to as proof that youth baseball overuse leads to Tommy John is this longitudinal study by the University of North Carolina. This study actually seemed to conclude that prior shoulder injury is actually the best predictor of future Tommy John surgery, closely followed by pitching a slider. Pitching in travel baseball is actually the 13th best indicator of future Tommy John surgery based on this study. This is not to say that over-use of youth pitchers has no effect on future injury, it just does not appear to be the biggest factor. In short, extreme over use of pitchers at a young age will lead to an increased injury risk but this is not the explanation for the increase in Tommy John surgeries we have seen recently in the MLB. One last possible explanation is that there are not actually any more UCL injuries than before. It is possible that modern medicine has made it easier for us to detect these injuries and that pitchers before were not able to properly identify their injury as a UCL tear requiring Tommy John. This explanation is the hardest to prove or to disprove because there is no way to go back and see how many injuries went unnoticed.
After going through this research, it is apparent that there is no one sole factor of the increase in Tommy John surgery. Our best guess is that it is a combination of the overuse of arms from a young age combined with the increase in velocity that has been recorded as of late. The Tommy John epidemic appears to be one without a clear solution. Pitch counts and reducing pitch velocity seems like a possible route to take but one that may or may not be effective. Overall, elbow injuries are a natural cause of throwing something as hard as professional pitchers do and a problem that will continue to exist for as long as pitchers are throwing 90-100 mph.