Why the Increase in Tommy John Surgery?

screenshotThere isn’t a hotter topic in baseball medicine than Tommy John surgery, and the dramatic increase in number of elbow injuries suffered by pitchers in the major leagues.  In 2013, 49 baseball players at the minor and major league levels underwent Tommy John surgery, and halfway into 2014, that number was 33. To put that number in perspective, there were only 29 players that underwent Tommy John in 2002, and and in 1992, there was just one recorded.  From the graph, you can see how dramatic the increase in the Tommy John procedure has become over the past 30 years since its creation.  That is a troubling and staggering curve to see, but what’s even more troubling is the number of adolescent, high school and college players that are sustaining these injuries. Below is data provided from my fellowship and shows this tremendous rise at the institution(7).

So why the increase? 

Why are so many players injuring their Ulnar Collateral Ligament?  This is the underlying question that many orthopedic sports medicine surgeons are asking, and there are two main contributing factors. Because of the nature of the ligament itself, the increase in these ligament injuries is due to the societal shift to one year-round specific sports, as well as what can be called “the radar effect”. While these aren’t new ideas, the potent mixture is creating an environment where pitchers are far too prone to injury, especially of the UCL. Dr. James Andrews had a a great interview about it on NBC sports. Additionally, my parent fellowship institution, ASMI, recently put out a position statement regarding this issue, which does an excellent job outlining the Tommy John injuries in baseball. However, I do have a slightly different take about the reason we have seen this massive increase.


UCL Biomechanics

To understand this better, we need to look at the UCL itself and understand the biomechanics of ligaments.  The UCL is a complex of three separate ligaments that originates from the medial epicondyle of the humerus and attaches at the sublime tubercle on the ulna bone.  The anterior oblique portion of the UCL is the primary restraint to valgus stress at the elbow, which is commonly engaged when throwing a ball, especially during the late cocking and acceleration phases of throwing. Although it is a tight band of tissue, it is still very active metabolically, and displays viscoelastic properties like other ligaments in the body. Animal studies have also shown that if a ligament is fatigued to a certain point over time, its mechanical strength can decrease as well.  This means that no matter how strong the normal ligament is, if enough damage has been done to it over time it can fail at a lower force than normal. This is especially true if the stress occurs repeatedly within a short time frame, but appears to also occur over a greater time frame as well.

Consider the amazing strength of the UCL in a major league pitcher.  Biomechanical studies have shown that the forces placed on the UCL during pitching can reach 64 Nm, which is quite close to the average strength before failure of a UCL (4).  To help take the load off the ligament, a group of muscles (flexor-pronator mass) help lighten the load.  However, if these muscles become fatigued, more of the force is translated to the ligament.  Even if it is not enough to tear the ligament, these forces over time can damage the ligament and make it more prone to future injury.  This becomes even more magnified if enough rest isn’t given to the arm prior to loading it again, which leads me to the large culprit for increased UCL injuries, in my opinion, year round baseball.

Thirty years ago, most athletes didn’t focus on one sport. The hyper-competitive environment in today’s sports is leading to more injuries, and UCL injuries in baseball is a prime example.

The Pitch Count

As we touched on previously, ligaments can be damaged over time, and this fact is magnified when the ligament and dynamic stabilizers supporting the ligament are fatigued and don’t get a chance to heal.  Let’s say a young 12 year old baseball player becomes enamored with the game and has quite the skill set as a pitcher.  The parents trying to encourage their son’s passion, sign him up for the local community team.  He performs fantastically as a pitcher, and is then invited to play club ball.  That year he records a 1,000 pitches for the season, as his parents did their research and found that to be a recommended ceiling.  The following 3 years he does the same routine, playing basically year round with two months off in December and January.  He goes on to high school following the same protocol, but now is bigger, stronger, and expanding his pitching repertoire. College and MLB scouts are excited about his prospects, but his senior year he blows out his UCL and undergoes Tommy John surgery.

I have seen this scenario before, and most orthopedic sports medicine surgeons have heard a similar story as well.  When you think about the professional pitcher who tore his UCL, their story might have been similar to our young 12 year old boy.  In this scenario, although he was held to only a 1,000 in game pitches, that doesn’t count the warm up pitches or practice.  When it is all said and done, this individual could have easily thrown 2,000 pitches a year, and probably more in high school.  Cumulatively, this could equate to well over 10,000 pitchers before he even turned 18, with not enough resting time.


Our bodies were not made to withstand this type of torment, and research supports this.  In one study, pitchers who played more than 8 months out of the year were at a 500% increased risk to undergo surgery then those that played less.  In addition, pitchers who averaged greater than 80 pitches/game were at a 400% increased risk (1).  Another study also showed that pitchers who pitched greater than 100 innings a year had a 3.5 times greater chance of sustaining a serious injury (2).

Most of the research focuses on annual numbers, but I believe this is a cumulative effect. If our young pitcher pitches an aggressive game and isn’t fully healed before the next time out to the mound, he could be doing damage to his UCL without knowing it. It may be microscopic and unknown, but it could be there and degrade the characteristics and strength of the ligament, placing it at future risk of rupture.  If our pitcher is pitching a majority of the year, he really isn’t given the UCL enough rest to recover from the gauntlet it was placed in previously.  Our body has an amazing ability to heal, but only if given an opportunity.  One of the major reasons major league pitchers suffer from this injury within the past few years is we are starting to see the first of the “year round” generation.  They have put  many cycles and so much force on the ligament that it finally tore after the years of abuse.  The fatigue and damage it sustained years before has affected its strength now, and it has finally caved to the enormous forces going across it.

“Radar Effect”screenshot 2

The last reason for increase in Tommy John surgery is what I have called the “radar effect”.  With so much focus on the fastball speed, from little league on up to the bigs, the amount of force with each pitch going across the UCL is astronomical.  In a study of adolescent pitchers with an average fastball of 65.8 mph, an average of 59N went across the elbow joint (3).  Now, imagine a major league pitcher dialing it up to 100 mph and the amount of force going across the ligament.  With such a competitive environment within Major League Baseball, everyone is trying to set the radar gun on fire. In 2002, a little over 70 pitchers had a mean velocity of over 90 mph.  in 2011, that number was over 160 (5).  That is a tremendous increase in the number of major league pitchers throwing in the 90s over the past few years.  Given this velocity “arms race”, pitchers are pushing their anatomical limits to try and maximize speed, and this can place the ligament in jeopardy.


In conclusion, the dramatic rise in UCL injuries is likely multi-factorial with two main culprits: year round baseball and the focus placed on the radar gun in today’s modern era.  Cumulative damage can be done to the elbow structures from high intensity, year round baseball and can place the pitcher at an increased risk both then and into the future.  While there are of course well established pitch count recommendations, these are not strict enough and don’t account enough for number of days of rest between outings and number of months a year to play, something we are currently discussing at MSHSAA.

Personally, I would like to see our society return to the “multi-sport” years and our young pitchers focus more on location and change of speed then setting the radar gun ablaze.



1.)Dun S, Loftice J, Fleisig GS, Kingsley D, Andrews JR: A biomechanical comparison of youth baseball pitches: Is the curveball potentially harmful? Am J Sports Med 2008;36(4):686-692.

2.)Fleisig GS, Andrews JR, Cutter GR, et al: Risk of serious injury for young baseball pitchers: A 10-year prospective study. Am J Sports Med 2011;39(2):253-257.

3.) Carl W. Nissen, Melany Westwell, Sylvia Õunpuu, Mausam Patel, Matthew Solomito and Janet Tate A Biomechanical Comparison of the Fastball and Curveball in Adolescent Baseball Pitchers. Am J Sports Med 2009 37: 1492

4.)Fleisig GS, Andrews JR, Dillman CJ, Escamilla RF: Kinetics of baseball pitching with implications about injury mechanisms. Am J Sports Med 1995;23 (2):233-239.

5.) According to fangraphs.com

6.) http://www.asmi.org/research.php?page=research&section=UCL


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