Baseball Pitching and Injury Avoidance: The Rotator Cuff, Labrum, and Tommy John Conundrum

Tommy Who?

For any of my baseball fans out there: I know you have heard of Tommy John surgery. For those that haven’t: Tommy John surgery refers to ligamentous replacement of the ulnar collateral ligament (UCL) at the elbow with a tendon of the opposite (non dominant) forearm, often done in baseball pitchers because of the high demand placed on this tissue during the throwing motion leading to tears. Tommy John was the first professional baseball player (1974) to undergo this surgery and made it famous for his return following the operation, pitching at similar levels to pre-injury 2 seasons later.

We Haven’t Improved UCL Injury Rates

In fact, this problem seems to be getting worse at the highest levels of play. A publicly available study concluded increased prevalence from 10% (in 2012) to 13% (in 2018) of professional baseball players required UCL reconstruction — and this number increases to 20% when just analyzing pitchers. I would like to emphasize that 1 in 5 professional pitchers required UCL reconstruction in the 2018 season. Looking at sub-professional levels seems to reveal similar results; this study looked at NCAA baseball players and observed 15% required season-ending UCL surgery — and concluded most (71.4%) of UCL injuries occurred in the fourth inning or later. Studies amongst high schoolers are less defined, but this study observed 10% of pitchers sustained injury to the upper extremity which required surgery. Discussing adolescents is trickier because the injury secondary to the same mechanisms presents differently. Players aged 6-12 tend to develop “little leaguers elbow” which presents as medial elbow pain and physiologically is considered apophysitis. Since this age group is typically not done growing, their bones have soft cartilaginous “growth plates”. The same suspect mechanics that result in over-tensioning of the UCL cause pulling at this growth plate, which results in inflammation at or near the medial epicondyle on the bone. This typically onsets sooner than UCL damage and thus, this condition sort of protects ligamentous injury from happening by being the painful limiting factor to seek care and restrict participation. Regardless, there seems to be a problem with UCL injury in throwers and it is undoubtedly getting worse, particularly at the higher levels.

What About the Shoulder?

Looking at prevalence of rotator cuff or internal shoulder injuries is more catchall because it can consist of one or many different types: muscle strains/tears, impingement syndrome, labrum damage, and tendinosis to name some. Expect this prevalence number to be higher simply because there are more injuries to consider. At the MLB level, 17% of reported injuries that sent players (78% of which were pitchers) to the disabled list were shoulder injuries. The most common shoulder injury reported was “inflammation” at 25.8%. Unfortunately, this study did not report on season ending injuries, or those requiring surgery. Comparing prevalence numbers to the UCL rates discussed above is thus an apples-to-oranges comparison. However, one study does exist which discovered a total of 581shoulder procedures done on 542 players (of which pitchers were 60%) occurred in the MLB and MiLB between 2012 and 2016. Of most interesting note: 89% of those that required shoulder surgery during those seasons were in the minors, and only 63% actually returned to sport. This lends evidence that shoulder injuries which require surgery happen before reaching the major leagues, and that shoulder surgeries in particular have a relatively high chance of being career-ending.

At the adolescent level, the same phenomenon which happens at the elbow seems to occur at the shoulder; the growth plate inflammation causing pain becomes the painful limiting factor and the athlete then seeks treatment, or rest, and avoids developing further injury to the shoulder. This study examined just that, and also concluded SLAP lesions (tears to the biceps tendon where it anchors into the “socket” or labrum) became more common in the high school player (18%), compared to junior high school (4.8%)

How Do We Avoid All of That? Pitch Counts? Mechanics??

The bottom line is that the throwing motion, and particularly the pitching sequence, is a very risky sports movement which can result in various injuries to both the elbow or the shoulder. It is a complex movement that has many consequences depending on various factors such as mechanics, developmental age, experience, and ability. The body of research dissecting pitching mechanics is growing rapidly, but the motion remains difficult to understand because of these factors. There is scant research linking technique directly to injury prevalence or type, but there are newer bodies of research linking certain types of deliveries to kinematic (torques, joint distraction forces, angular velocities, etc.) consequences, and those kinematics have been linked to injury. It is safe to say technique matters for reducing stress at the shoulder or elbow, and balancing this with overall load is imperative to navigating what can otherwise seem like an injury minefield. Adjusting mechanical factors in the throwing motion will certainly have resultant changes in the forces at these joints, but it is not as simple as fitting each player into the same delivery to mitigate risk. Altering one variable can decrease forces over one area and increase them on another. This leads to a potential conundrum: do we transfer stress to or from the elbow or shoulder? This is why it is imperative each player is looked at individually and programs be tailored to the particular athlete.

Pain or no pain, I recommend all baseball players, and particularly pitchers, get their kinematics measured to understand their personal risk factors and potentially make adjustments to mitigate injury (and improve performance!). If you have a history of pain at the shoulder or elbow at any level or age, I strongly recommend you reach out for a consult and kinematic assessment so a rehabilitation and/or mitigation program can be developed that’s tailored specifically for you.