Many Baseball Players Suffer Performance Declines Following UCL Injury

Research Review

Peters SD, Bullock GS, Goode AP, Garrigues GE, Ruch DS, Reiman MP. The success of return to sport after ulnar collateral ligament injury in baseball: A systematic review and meta-analysis. J Shoulder Elb Surg. 2018;27(3):561-571. doi:10.1016/j.jse.2017.12.003.


Ulnar collateral ligament injury (UCLI) in baseball players has been on the rise for the last 2 decades.  Many players return to play following a course of conservative treatment or reconstructive surgery.  However, research has not clearly elucidated the level at which these players return to sport (RTS) or their pitching statistics following RTS.


The purpose of this systematic review was to report and clarify RTS proportions (with and without performance statistics) after UCLI.


The published literature was searched through October 2016. Inclusion criteria were as follows: (1) baseball players at any competition level who incurred a full, partial, or sprained UCLI, (2) surgical and nonsurgical UCLI, (3) prospective or retrospective cohort, or case studies with a population greater than 10 athletes, (4) published in a peer reviewed journal, (5) published RTS criteria or proportions, and (6) written in English.

Two authors independently conducted a quality assessment.   Data, including player statistics (when available), were extracted into a customized database by a single author and confirmed by a second author.   RTS was defined as any athlete returning to any level of competitive sport.  Return to sport at previous level (RTSP) was defined as return to competitive sport, at a level the athlete was playing at before injury or higher.

Key Results

  • 22 studies were included and all were cohort studies or case series.
  • Two studies received high-quality scores, 4 were moderate quality, and 16 were low quality.
  • RTS criteria were assessed in 2020 baseball players.
  • Overall RTS proportion was 90% (95% CI, 86% to 94%) and overall RTSP proportion was 79% (95% CI, 75% to 84%) regardless of treatment type.
  • UCL reconstruction showed an overall RTS proportion of 92% and an overall RTSP of 83%.
  • RTS and RTSP proportions were 89% and 78% for Major League Baseball players, 91% and 67% for Minor League Baseball players, 95% and 92% for collegiate players, and 93% and 83% for high school players
  • Increased earned run average (ERA), walks and hits per innings pitched (WHIP), decreased innings pitched, and decreased fastball velocity were found after UCLI in MLB players.

Study Limitations

  • Poor quality assessment of primary studies included in the review.
  • High drop-out rate of primary studies included in the review decreases confidence in findings.
  • Follow-up time of primary studies was variable (2 to 10 years) which could impact results related to RTSP.
  • Several primary studies did not differentiate between players returning to the same level (or higher) and players returning to a lower level.
  • Several primary studies did not clearly demarcate or define RTS vs. RTSP.

Closing Thoughts & Practical Implications

The primary finding from this systematic review is that fewer baseball players return to sport at the previous level than those who simply return to sport.  Also, pitching performance decrease regardless of the surgical procedure performed.  There was only a small difference in RTS proportions across competition levels with college players demonstrating the highest proportion of RTS at 95%.  MLB players demonstrated the lowest success proportion at 89%.  UCL reconstruction demonstrated the highest RTS proportions compared to revision and repair procedures.  More research is needed to accurately assess and compare RTS proportions by surgical intervention and to investigate non-surgically managed baseball players.  Only one low quality study reported nonsurgical RTS rates (93%).

A 79% RTSP rate suggests many baseball players are able to return to their prior level of competition.  However, this rate was higher for those undergoing first time UCL reconstruction (83%) vs. revision (60%).  In professional players, there was a large variance in RTS (91%) and RTSP (67%).  This suggests, most MLB players will ultimately return to play but many do so without progressing to the same or higher levels.  This data does not support the opinion that players undergoing UCL reconstruction will ultimately perform at a higher level following surgery.

Pitching statistics are significantly reduced following UCLI.  Velocity, ERA, and WHIP all decline following UCL surgery.  Therefore, even when baseball players do return to the same level of competition following UCLI, their performance does not return to prior levels.  Follow-up time of the included studies could influence these results.  However, based on the current body of evidence, baseball players who sustain a UCLI are fighting an uphill battle back to their prior level of performance.  A better understanding about risk factors and injury risk reduction strategies would be the optimal measure to combat the epidemic of UCL injuries occurring across all levels of baseball.

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