Sports Medicine Research: In the Lab & In the Field: The High School Throwing Elbow – What's “Normal”? (Sports Med Res)
Monday, August 22, 2011

The High School Throwing Elbow – What's “Normal”?

Magnetic resonance imaging of the throwing elbow in the uninjured, high school-aged baseball pitcher.

Hurd WJ, Eby S, Kaufman KR, Murthy NS. Am J Sports Med. 2011 Apr;39(4):722-8. Epub 2011 Jan 12.
http://www.ncbi.nlm.nih.gov/pubmed/21228309

There is no question that baseball is one of the most popular sports amongst children in America. There is also no question that with increased popularity and participation there is an inherent increase in the incidence of throwing injuries. While certain interventions have been implemented over the years in an effort to avoid injuries in the younger throwing athlete, such as limiting pitches/week and the avoidance of throwing breaking pitches, injuries can, and will, still occur often requiring diagnostic imaging. The American Journal of Sports Medicine recently published two studies by Hurd et al (http://www.ncbi.nlm.nih.gov/pubmed/21228309 and http://www.ncbi.nlm.nih.gov/pubmed/21335342) examining the elbow in high school baseball pitchers. While recent studies have shown that anatomical changes to the elbow and shoulder visible on MRI are quite common in asymptomatic elite overhead athletes, no such studies exist focusing on younger athletes. However, many of us are not working with elite level overhead athletes and knowing what tissue adaptations are occurring in the high school-aged athletes is crucial to understanding what may or may not be at the heart of elbow pain. In the first study by Hurd et al., 23 asymptomatic high school-aged pitchers (14-19 years) were recruited to determine if anatomical changes are present in the throwing elbows. All subjects completed a physical to confirm that they were asymptomatic followed by a bilateral elbow MRI utilizing the non-dominant elbow as a control. Differences in ligamentous, musculotendinous, osteoarticular and neural structures were examined. The most common findings in the subjects dominant elbows included thickening of the anterior band of the UCL (65%), ulnotrochlear subchondral sclerosis (61%) and ulnotrochlear osteophytes located on the posterior medial tip of the olecranon (35%) with 43% of the subjects presenting with multiple MRI findings.

Understanding that these degenerative findings present at an early age and are visible on MRI is of importance for ATCs. As health care providers we can begin to eliminate certain positive MRI findings as possible sources of pain and dysfunction in the high school-aged pitcher. The authors suggest that the subjects in this study presenting with multiple degenerative findings upon MRI could potentially be at an increased risk of a UCL tear and that these MRI findings could be a predictor of future elbow injury. What isn't so clear is why the UCL thickening occurs. Currently it remains unknown if the thickened UCL is a positive or a negative finding for pitchers. It could be argued that the thicker ligament would be able to resist greater valgus forces throughout the pitching motion and potentially prevent injury. On the other hand, these changes could be construed as being degenerative eventually manifesting as a ligament tear. Either way, further investigation is necessary to evaluate the structural composition of this thickened UCL. For further insight on this topic, a SMR post detailing the author's follow-up to this study can be found here. In it, the author examines the relationship between elbow distraction forces and UCL thickening on MRI. Are you surprised that the pitching elbow exhibits these degenerative osseous changes and UCL thickening at such an early age? What do you believe could be at the heart of the UCL thickening?

Written by: Mark Rice
Reviewed by: Stephen Thomas

8 comments:

Mark Sutherlin said...

I agree that youth baseball injuries are a growing concern among sport medicine professionals. I do see value in obtaining MRIs to look at the adaptation of stresses of the elbow for research purposes. Studies over time may identify potential injury development or an understanding of adaptation, both positive and negative, as a result of the throwing motion. The use of imaging still has limitations which include, how often images need to be administered to tract adaptations or how close to an injury do these images need to be conducted to identify less severe damage or potential risk factors for injury.

The throwing motion is such an abnormal and mechanically inefficient movement pattern, that I believe that body adapts to the stresses both positively and negatively. Thickening of the UCL allows for the body to absorb the demands of the repetitive throwing motion. However, this thickening is also causing micro trauma to the ligament each time during the throwing motion that could lead to individual weakened areas more susceptible to injury.

I would be interested to see the effect of the increased demand on the elbow as youth pitchers transition from the smaller to larger playing fields. Is there a significantly greater demand that is place on the elbow pitching from the further distance at a young age? I would also be curious to see how changes differ from athletes who specialize playing baseball year round compared to baseball season only in pitchers with regards to development of UCL degeneration. Additional information as to how youth respond during skill development would allow for better understanding to how and why these injuries occur.

Mark A. Rice said...

Hi Mark. Thanks for reading. I think at you bring up some great points. The thickening of the UCL, and i agree with your assessment, can be viewed as both a positvie and a negative. While it can conceivably resist greater forces, the structure has to be damaged and repaired first to do it.

At the heart of the issue is A. The overhand throwing motion's sheer brutality to all structures involved and B. the UCL's structure itself. Other studies have shown biomechanically that it can only counteract about 51% of the valgus load placed on it while throwing, with the rest of the load being transferred elsewhere. That said, we might be seeing a perfect storm, of sorts, in regards to potential UCL injuries.

As far as youth pitching goes, and youth sports in general, there is so much that is still open for investigation. I honestly believe that youth sports injury studies for sports medicine is a well that is very deep and that many people could investigate notions like the one you put forth, Mike, and have very distinguished careers. I love your thought process.

Please be sure to share, like, and +1 any of the SMR posts that you respond to. SMR is only as strong as its followers. Please don't be afraid to pass SMR along so that all of us can continue to grow. Thanks again!

Ken Becker ATC said...

Mark,

After reading both posts by the "Marks", a couple of other questions arise. First, at the youth level ( K-7), coaching is extremely inconsistent regarding pitching. If a bad habit is created, it starts here. Once the athlete enters the Legion or older Babe Ruth leagues (8-12), coaching becomes more consistent, but again is less structured technically. High school programs try to make a positive impact through their feeder schools, but are hampered by the Legion and Babe Ruth system.
Second, at the collegiate level, where I am vested, we see the repercussions of this advice (or lack there of) amplified into horrible mechanics, shoulders and elbows with issues created years earlier.
Within our baseball program, though our summer and weekend camps, we have tried to create a good balance of information for parents and the athlete to draw from, underscoring the need for mechanics first. But.....baseball is full of information regarding pitching mechanics, some good, some not.
After reading through the other posts about Lumbro-sacral control, I believe that these two issues go hand in hand. Meaning, pitching is not just hurling a ball toward home plate, but a well orchestrated succession of movements, done correctly, can reduce the incidences of injury at all levels of play.
Keep the research coming, its always interesting to read and digest.

Aja Corchado said...

I found this article interesting because we as athletic trainers are always dealing with different types of "normal" when assessing different athletes. When an athlete is injured, we don't know exactly what is considered normal for them unless we have a history with that athlete and was able to get a baseline for them. I think this study is helpful because it shows that baseball players do go through changes and their bodies adapt to the mechanisms they use. This allows AT's to get a better idea and understanding of what is going on with the UCL during the motions and maybe figure out why injuries occur. My question is if any of these players that were examined continued their baseball careers in college or some other league and if the clinicians did a follow up? I would be curious to see if there were any more changes or if they suffered any type of injury later on as a result of the thickening of the UCL. Also, I would like to know if they asked how many years each player had been pitching and if there showed any differences depending on the length that they have been playing or if they still all showed similar changes. Lastly, I think the study should limit the players they choose to examine based on the type of pitches they throw, such as just fastballs or a combination of pitches like fastballs, curveballs, and others. I know that today it is a controversial topic of young baseball pitchers throwing curveballs because it can cause injury and damage their arm. It would be interesting to see what type of changes occur depending on the types and frequency of pitches the players throw.

Andrew Broske said...

This article is interesting to me because now more than ever emphasis is being put on the pitch count of young pitchers. Until recently young pitchers were throwing too much and they were blowing out their elbows later in life. Therefore as athletic trainers it's important to know how long the baseball player has been a pitcher and to keep an eye for anything concerning. Something that interesting to me was that many of the pitchers studied had abnormalities associated with their elbow. This just shows that what baseball is doing by limiting a young pitchers pitches is important. Also something that is important to note is that what is "normal" for some may not be normal for others. Going along with this article a question that I have is, does limiting the number of pitches in youth baseball lower the rate of these abnormalities? Also are these abnormalities natural for all baseball pitchers and ultimately do these abnormalities place a greater risk of injury later in life? It would be interesting to follow youth pitchers later in life and see if what if any injures had occurred. Following pitcher through their youth will also give proof to the guidelines being set by youth baseball.

One last thing that I think is important to examine is the way coaches follow guidelines being set. As an athletic trainer I have seen coaches completely disregard guidelines or what we tell them regarding a players injury. Causing pitchers to pitch on a couple days rest can be detrimental to the pitchers health, but some coaches only look at the game in hand. They will do anything to win right now and not worry about the consequences later.

Joe Ayres said...

This article makes an interesting point that there are not many studies being done on younger populations. This is critical and should be changed because it could open the door to a whole new range of research and rehabilitation options. By studying the structural changes that occur in the younger population, we will gain insight on how these athletes are affected as they progress to college level and possibly even professional level of play. As a result, we could discover how these structural changes are caused by the performance of the athletes. The key is to understand why these structural degenerations are caused which will lead to how they affect the population. The best way to track their progress is to find out how the athletes develop by starting when they are younger and monitoring their change as they progress to higher levels of competition. If we are able to understand the impact of these structural degenerations in the high school level athlete, we will glean an insight as to how the degenerations manifest as time and increased stresses are placed on the structures involved.

Merisa Rudy said...

This article really highlights the need for us, as ATs , to know our athletes and to recognize their limits. Baseball pitching is a reminder of individual positions, but we must be aware of athletes that aren't as in the spotlight such as soccer players or lacrosse players. This is an awesome start and opens up a great discussion for athletes across the board to be monitored more efficiently.

Stephen Thomas, PhD, ATC said...

Everyone thanks for the comments. I agree that we need more longitudinal research examining these kids overtime to better understand how these changes occur and also if they relate to injury. These studies will be very powerful clinically and provide us with better knowledge to prevent elbow injuries.

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