Fastball Quality After Ulnar Collateral Ligament Reconstruction in Major League Baseball Pitchers

Abstract

Background: The ulnar collateral ligament (UCL) is essential for elbow stability during pitching. In professional baseball, the fastball (FB) is the most commonly used pitch, making postrecovery FB performance after UCL reconstruction (UCLR) a crucial aspect to consider.

Hypotheses: (1) Pitchers undergoing UCLR would show no significant changes in performance metrics compared with nonoperated pitchers with similar FB velocity and spin rate, and (2) no significant variance would be found in these metrics within the operated pitchers concerning their preinjury anthropometric characteristics and pitching performance metrics.

Study design: Cohort study; Level of evidence, 3.

Methods: The study included 91 Major League Baseball (MLB) pitchers who underwent primary UCLR between January 1, 2015, and December 31, 2021. A matched 1:1 control group of MLB pitchers without UCLR injuries was established. Publicly available pitch metrics and anthropometric data were compared between the study and control groups.

Results: Disparities in several performance metrics emerged during the first postreturn year (PRY1), including FB use percentage (P = .029), fielder independent pitching (FIP) (P = .021), and standardized FB runs above average per 100 pitches (wFB/C) (P < .001). Subgroup analysis within the UCLR group revealed a negative correlation between presurgery mean FB velocity and its subsequent change (P < .001) and a positive correlation with changes in FIP (P = .025) from the index year to PRY1. A negative correlation was observed between FB use percentage in the index year and its change by PRY1 (P = .002). By the second postreturn year, no significant differences were found in these performance metrics. No factors were significantly related to prolonged recovery time.

Conclusion: Although FB velocity and spin rate remained consistent, significant differences were observed in FB use percentage, FIP, and wFB/C in PRY1. However, by second postreturn year, these differences were no longer significant. No specific risk factors were identified concerning prolonged recovery time between pre-UCLR FB pitching metrics and the physical anthropometric data. These results suggest that although the short-term postsurgery period may affect more specialized pitching metrics, the basic pitching performance metrics, as hypothesized, remain largely unaffected by UCLR.

Keywords: baseball; elbow; pitching; ulnar collateral ligament reconstruction.