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Decreased Upward Vertical Movement for Fastballs After Ulnar Collateral Ligament Reconstruction in Major League Baseball Pitchers

Open AccessPublished:August 17, 2022DOI:https://doi.org/10.1016/j.asmr.2022.06.016

      Purpose

      To analyze the velocity and movement of the 4-seam fastball, curve, and slider thrown before and after ulnar collateral ligament reconstruction (UCLR) in Major League Baseball pitchers using PITCHf/x data.

      Methods

      Velocity and movement data of the 4-seam fastball, curve, and slider were collected for 3 time frames (12-24 months before the date of UCLR as an uninjured baseline, 12-24 months after the date of UCLR, and 24-36 months after the date of UCLR). Pitchers were separated into 3 age groups (<26, 26 to 31, and >31 years). A paired t-test for means was used to assess mean differences between 2 time periods and a generalized linear model, with time-dependent covariance structure and age group as a covariate, was used to determine differences across time. All analyses were performed using SAS, version 9.4.

      Results

      Vertical movement of the 4-seam fastball decreased in the 24 to 36 months’ postoperative time frame, compared with 12 to 24 months’ preoperatively (9.46 to 9.14 inches, P = .032). Movement decreases in the 4-seam fastball were not age-related. Velocity did not significantly change for any pitch and movement did not change for the slider or curve pitches.

      Conclusions

      Following UCLR, Major League Baseball pitchers experienced no changes in horizontal or vertical movement or velocity of the curve or slider in either time frame. Decreased upward vertical movement of the fastball occurred after UCLR at final follow-up, but no change was observed in velocity. Similar trends in pitch movement and velocity effects were observed regardless of age.

      Level of Evidence

      IV, case series.
      The first ulnar collateral ligament reconstruction (UCLR) was performed in 1974, and the number of Major League (MLB) Baseball pitchers undergoing UCLR has gradually increased.
      • Conte S.A.
      • Fleisig G.S.
      • Dines J.S.
      • et al.
      Prevalence of ulnar collateral ligament surgery in professional baseball players.
      ,
      • Mahure S.A.
      • Mollon B.
      • Shamah S.D.
      • Kwon Y.W.
      • Rokito A.S.
      Disproportionate trends in ulnar collateral ligament reconstruction: Projections through 2025 and a literature review.
      Of those who have undergone UCLR, between 5% and 33% are unable to return to their previous high level of pitching performance.
      • Cain E.L.
      • McGonigle O.
      Return to play following ulnar collateral ligament reconstruction.
      ,
      • Ford G.M.
      • Genuario J.
      • Kinkartz J.
      • Githens T.
      • Noonan T.
      Return-to-play outcomes in professional baseball players after medial ulnar collateral ligament injuries: Comparison of operative versus nonoperative treatment based on magnetic resonance imaging findings.
      Previous studies have reported conflicting results about pitching performance after UCLR in MLB pitchers, with some showing no change in performance and others showing declining performance postoperatively.
      • Griffith T.B.
      • Duralde X.A.
      Successful performance after ulnar collateral ligament reconstruction: An analysis of 88 drafted professional baseball pitchers with a matched comparison cohort.
      • Jiang J.J.
      • Leland J.M.
      Analysis of pitching velocity in major league baseball players before and after ulnar collateral ligament reconstruction.
      • Keller R.A.
      • Marshall N.E.
      • Guest J.-M.
      • Okoroha K.R.
      • Jung E.K.
      • Moutzouros V.
      Major League Baseball pitch velocity and pitch type associated with risk of ulnar collateral ligament injury.
      • Lansdown D.A.
      • Feeley B.T.
      The effect of ulnar collateral ligament reconstruction on pitch velocity in major league baseball pitchers.
      • Makhni E.C.
      • Lee R.W.
      • Morrow Z.S.
      • Gualtieri A.P.
      • Gorroochurn P.
      • Ahmad C.S.
      Performance, return to competition, and reinjury after Tommy John surgery in major league baseball pitchers: A review of 147 cases.
      • Swindell H.W.
      • Trofa D.P.
      • Confino J.
      • Sonnenfeld J.J.
      • Alexander F.J.
      • Ahmad C.S.
      Performance in collegiate-level baseball players after elbow ulnar collateral ligament reconstruction.
      In 2007, PITCHf/x (Sportvision Inc./SportsMEDIA Technology, Durham, NC)
      BrooksBaseball.net
      Home of the PITCHf/x Tool.
      ,
      Pitch Info: Pitch Classifications, Data Management, Consulting.
      was introduced into MLB stadiums to track pitch characteristics, such as pitch type, velocity, release point, and movement. Several studies have used these data, along with conventional baseball statistics, to investigate the effects of UCLR on pitchers.
      • Jiang J.J.
      • Leland J.M.
      Analysis of pitching velocity in major league baseball players before and after ulnar collateral ligament reconstruction.
      • Keller R.A.
      • Marshall N.E.
      • Guest J.-M.
      • Okoroha K.R.
      • Jung E.K.
      • Moutzouros V.
      Major League Baseball pitch velocity and pitch type associated with risk of ulnar collateral ligament injury.
      • Lansdown D.A.
      • Feeley B.T.
      The effect of ulnar collateral ligament reconstruction on pitch velocity in major league baseball pitchers.
      • Makhni E.C.
      • Lee R.W.
      • Morrow Z.S.
      • Gualtieri A.P.
      • Gorroochurn P.
      • Ahmad C.S.
      Performance, return to competition, and reinjury after Tommy John surgery in major league baseball pitchers: A review of 147 cases.
      Studies investigating velocity have reported contradicting results, with some studies showing no change in fastball velocity,
      • Jiang J.J.
      • Leland J.M.
      Analysis of pitching velocity in major league baseball players before and after ulnar collateral ligament reconstruction.
      ,
      • Keller R.A.
      • Marshall N.E.
      • Guest J.-M.
      • Okoroha K.R.
      • Jung E.K.
      • Moutzouros V.
      Major League Baseball pitch velocity and pitch type associated with risk of ulnar collateral ligament injury.
      whereas another showed a decrease in fastball velocity.
      • Lansdown D.A.
      • Feeley B.T.
      The effect of ulnar collateral ligament reconstruction on pitch velocity in major league baseball pitchers.
      Another study reported that pitchers threw fewer pitches in the strike zone after surgery; however, performance after UCLR was similar to that seen in a control group over the same period of study.
      • Makhni E.C.
      • Lee R.W.
      • Morrow Z.S.
      • Gualtieri A.P.
      • Gorroochurn P.
      • Ahmad C.S.
      Performance, return to competition, and reinjury after Tommy John surgery in major league baseball pitchers: A review of 147 cases.
      From these studies, it is difficult to determine the effect of UCLR on pitch characteristics and investigations on how UCLR affects pitch movement are limited. Pitch movement, as measured in inches by the PITCHf/x system (1 inch = 2.54 cm), is reported in horizontal and vertical vectors. Horizontal movement (Hmov) is the right or left movement of the pitch compared with the initial trajectory, with positive values to the left side of home plate and negative values to the right side of home plate from the pitcher’s perspective (Fig 1). Vertical movement (Vmov) uses spin deflection of the baseball to determine movement of the pitch without the effect of gravity. A pitch with a positive vertical movement is a pitch with a high rate of backspin, which causes the pitch to “break up,” whereas a pitch with forward spin does not resist the force of gravity and will break down. The 4-seam fastball has a high rate of backspin, which causes a positive Vmov. It also tends to move toward the same side of home plate as the pitcher’s throwing arm. This would cause a negative Hmov value for a right- handed pitcher (Fig 1). The curve drops farther than would be expected due to gravity because of forward spin, and moves to the opposite side of home plate from the pitcher’s hand. The curve therefore typically has a positive Hmov and a negative Vmov when thrown by a right-handed pitcher. The slider has a horizontal spin axis

      Spin Rate Part II: Spin Axis & Useful Spinches Driveline Baseball. Published November 28, 2016. Accessed June 23, 2021. https://www.drivelinebaseball.com/2016/11/spin-rate-part-ii-spin-axis-useful-spin/

      that usually leads to a positive Hmov and Vmov when thrown by a right-handed pitcher. However, a small group of pitchers throw a slider with a negative Vmov (Figs 1 and 2).
      Figure thumbnail gr1
      Fig 1Demonstration of expected pitch movements for a right-handed pitcher. The 4-seam fastball tends to rise relative to the expected path and run in the direction of the pitcher’s throwing arm. The curve tends to drop farther than the expected path and run away from the pitcher’s throwing arm. The slider tends to drop less than would be expected due to gravity and it runs away from the pitcher’s throwing arm.
      Figure thumbnail gr2
      Fig 2Demonstration of pitch spin for a right-handed pitcher. The 4-seam fastball has a backspin, while the curve has a forward spinches The slider has a clockwise spin for right-handed pitchers.
      The purpose of this study was to analyze the velocity and movement of the 4-seam fastball, curve, and slider thrown before and after UCLR in MLB pitchers using PITCHf/x data. We hypothesized that pitchers would return to their pre-UCLR velocity and pitch movement within 36 months after UCLR.

      Methods

      A data set of pitchers who have undergone UCLR is established and maintained at MLB Reports (www.mlbreports.com) as described previously.

      TJ Surgery: AllTime MLB List. MLB Reports. Published April 21, 2012. Accessed June 23, 2021. https://mlbreports.com/tj-surgery/

      • Smith R.
      • Lombardo D.J.
      • Petersen-Fitts G.R.
      • et al.
      Return to play and prior performance in Major League Baseball pitchers after repair of superior labral anterior-posterior tears.
      • Wilson A.T.
      • Pidgeon T.S.
      • Morrell N.T.
      • DaSilva M.F.
      Trends in revision elbow ulnar collateral ligament reconstruction in professional baseball pitchers.
      From these data, MLB pitchers who had UCLR from 2008 to 2015 were identified. Pitchers were excluded if they had undergone more than 1 UCLR in their careers, or if they did not have at least 20 pitches of 1 type in the 12- to 24-month preoperative, 12- to 24-month postoperative, and 24- to 36-month postoperative time frames. Due to the public nature of all data used, institutional review board approval was not required.
      Demographic data recorded included handedness, type of pitcher (relief or starting pitcher), date of surgery, and age at surgery. Separately, pitch data were collected from a publicly available PITCHf/x database (DIY Baseball, LLC, Saratoga Springs, NY) and analyzed by pitch type (4-seam fastball, curve, slider).
      BrooksBaseball.net
      Home of the PITCHf/x Tool.
      ,
      Pitch Info: Pitch Classifications, Data Management, Consulting.
      Information related to the 4-seam fastball, curve, and slider pitches were collected for each pitcher in 3 distinct time frames: 12 to 24 months before surgery, 12 to 24 months after surgery, and 24 to 36 months after surgery. Measures collected for each pitch type included the number thrown, average velocity, average horizontal movement, and average vertical movement. For all left-handed pitchers, the horizontal axis was adjusted to match that of a right-handed pitcher for analysis purposes. Differences in velocity and movement of each pitch were compared between the preoperative time frame (12- 24 months before surgery), and the 2 postoperative time frames (12-24 months and 24-36 months after surgery) for each individual pitcher. To adjust for age, pitchers were separated into age groups, those who underwent UCLR before the age of 26, between 26 and 31, and after 31 years of age.
      Statistical analyses were performed using paired t-tests for 2 means or using a repeated measures analysis with age group covariate using SASv9.4. Five different correlation structures were considered to capture change over time: unstructured, simple, compound symmetry, AR(1), and AR(1) with random intercept. Akaike information criterion, with small sample size correction, was used to determine the best model fit and final model estimates. Descriptive statistics for age and outcome measures and final model fit are reported in Appendix Tables 1 and 2, respectively, available at www.arthroscopyjournal.org. Profile plots displaying movement trends among pitchers are reported in Appendix Figure 1, available at www.arthroscopyjournal.org.

      Results

      A total of 46 pitchers were included in our study (Fig 3). Mean age at the time of surgery for pitchers was 28.0 years (age range 21-37 years old) and 34.8% (16/46) underwent surgery before the age of 26 years, whereas 50.0% (23/46) underwent surgery between the ages of 26 and 31 years. Of the 46 pitchers included in the study, 87.0% (40/46) met inclusion criteria for 4-seam fastball, 63.0% (29/46) met inclusion criteria for curve, and 56.5% (26/46) met inclusion criteria for slider.
      Figure thumbnail gr3
      Fig 3Inclusion flowchart. (UCLR, ulnar collateral ligament reconstruction.)

      Overall Analysis

      Velocity and horizontal movement did not change significantly for the 4-seam fastball pitch in either postoperative time frame when compared with preoperative values (Table 1). However, a statistically significant decrease was observed in 4-seam fastball movement in the vertical direction (9.46 inches [24.03 cm] vs 9.14 inches [23.22 cm], P = .032) when comparing the preoperative time frame with the 24- to 36-month postoperative time frame. Vertical movement of the slider and curve did not change for either postoperative time frame, compared with preoperative values (Table 1).
      Table 1Overall Velocity and Movement 12-24 Months Before Surgery Versus 12-24 Months After Surgery (First P Value) and 12-24 Months Before Surgery Versus 24-36 Months After Surgery (Second P Value)
      PreoperativePostoperative
      PitchMeasurement12-24 Months12-24 MonthsP Value24-36 MonthsP Value
      Four-seam fastball n = 40Velocity (mph)93.19 ± 5.7592.92 ± 5.17.30992.95 ± 5.08.305
      Hmov (inches)–5.34 ± 2.19–4.95 ± 5.40.173–4.99 ± 3.20.093
      Vmov (inches)9.46 ± 1.999.13 ± 2.40.0599.14 ± 1.94.032
      Curve n = 29Velocity (mph)78.87 ± 8.9279.26 ± 8.61.14079.20 ± 8.51.293
      Hmov (inches)5.16 ± 4.395.07 ± 5.16.7045.14 ± 5.27.968
      Vmov (inches)–5.47 ± 4.63–5.59 ± 6.22.695–5.59 ± 6.31.743
      Slider n = 26Velocity (mph)84.75 ± 6.0084.40 ± 7.68.35984.46 ± 6.56.329
      Hmov (inches)1.87 ± 4.611.63 ± 3.39.3791.53 ± 5.10.240
      Vmov (inches)1.44 ± 4.271.69 ± 9.62.5331.14 ± 7.94.396
      NOTE. P values in bold are statistically significant.
      Hmov, horizontal movement; Vmov, vertical movement.

      Determining the Influence of Pitcher Age

      Pitchers who underwent UCLR between the ages of 26 and 31 years experienced a significant decrease in 4-seam fastball velocity at both 12 to 24 months and at 24 to 36 months after surgery (93.22 vs 92.53, P = .023, vs 92.41, P = .007) (Table 2). However, players who underwent UCLR before the age of 26 years or after 31 years did not experience any significant change in their 4-seam fastball velocity. Pitchers with UCLR before the age of 26 years experienced a significant decrease in the amount of horizontal movement of their 4-seam fastball in both time frames, 12 to 24 months after surgery (5.84 inches [14.83 cm] vs 4.95 inches [12.57 cm], P = .020) and 24 to 36 months after surgery (5.84 inches [14.83 cm] vs 5.03 inches [127.8], P = .016). Four-seam fastball vertical movement decreased for both 26- to 31-year-olds (9.39 inches [23.85 cm] vs 8.82 inches [22.40 cm], P = .014) and those older than 31 years (9.51 inches [24.16 cm] vs 8.79 inches [22.33 cm], P = .001) for the 24 to 36 months postoperative time frame. Pitchers who underwent UCLR between ages 26 and 31 years experienced a significant decrease in the amount of slider horizontal movement in the 12- to 24-month postoperative time frame (1.72 inches [4.37 cm] vs 1.21 inches [3.07 cm], P = .035, Table 2).
      Table 2Velocity and Movement 12-24 Months Before Surgery Versus 12-24 Months After Surgery (first P value) and 12-24 Months Before Surgery Versus 24-36 Months After Surgery (second P value) by Age Group
      PitchMeasurementAge Group (Years Old)12-24 Months Preoperative12-24 Months PostoperativeP Value24-36 Months PostoperativeP Value
      Four-seam Fastball

      <26, n = 15

      26-31, n = 18

      >31, n = 7
      Velocity (mph)<2693.52 ± 4.3793.65 ± 3.73.80093.63 ± 4.13.806
      26-3193.22 ± 5.9492.53 ± 6.39.04092.41 ± 2.25.007
      >3192.43 ± 9.4292.35 ± 4.67.90892.88 ± 6.97.473
      Hmov (inches)<26–5.84 ± 2.69–4.95 ± 4.00.020–5.03 ± 2.75.016
      26-31-5.11 ± 1.18–4.83 ± 4.72.485–4.84 ± 2.83.363
      >31–4.90 ± 3.59–5.27 ± 12.19.744–5.31 ± 6.19.515
      Vmov (inches)<269.53 ± 1.539.59 ± 1.21.8189.69 ± 0.840.527
      26-319.39 ± 2.328.93 ± 3.22.0818.82 ± 2.50.014
      >319.51 ± 2.778.68 ± 2.78.1398.79 ± 2.33.001
      Curve

      <26, n = 12

      26-31, n = 13

      >31, n = 4
      Velocity (mph)<2679.11 ± 7.1979.93 ± 7.30.08479.73 ± 7.13.260
      26-3179.04 ± 9.0278.94 ± 9.43.73378.95 ± 10.76.827
      >3177.58 ± 18.2178.29 ± 12.41.51278.39 ± 7.94.510
      Hmov (inches)<264.77 ± 4.754.48 ± 3.51.4264.79 ± 5.56.978
      26-315.23 ± 3.295.24 ± 5.61.9825.19 ± 5.00.917
      >316.07 ± 8.736.29 ± 9.31.6436.07 ± 7.18.982
      Vmov (inches)<26–5.64 ± 4.41–5.74 ± 7.25.859–5.47 ± 8.19.802
      26-31–5.37 ± 5.55–5.43 ± 7.27.898–5.51 ± 6.55.815
      >31–5.26 ± 4.62–5.66 ± 2.24.618–6.27 ± 1.95.090
      Slider

      <26, n = 10

      26-31, n = 12

      >31, n = 4
      Velocity (mph)<2684.36 ± 7.6484.99 ± 7.42.27784.37 ± 6.28.987
      26-3184.61 ± 5.1884.04 ± 6.94.26184.29 ± 7.70.434
      >3186.14 ± 4.9384.81 ± 10.29.38185.21 ± 6.67.246
      Hmov (inches)<262.19 ± 6.441.85 ± 1.88.5651.77 ± 4.15.431
      26-311.72 ± 4.511.21 ± 5.65.0351.01 ± 7.49.069
      >311.54 ± 2.002.34 ± 0.36.3302.45 ± 0.17.287
      Vmov (inches)<260.80 ± 7.271.17 ± 10.81.4850.44 ± 11.56.581
      26-312.01 ± 2.332.75 ± 7.33.2412.32 ± 3.30.414
      >311.31 ± 2.50–0.18 ± 10.84.318–0.67 ± 7.86.134
      NOTE. P values in bold are statistically significant.
      Hmov, horizontal movement; mph; miles per hour; Vmov, vertical movement.

      Repeated Measures Analysis

      Analogous results were observed across time periods. Decreases in the 4-seam fastball vertical movement were detected for both 12 to 24 months (P = .0475) and 24 to 36 months (P = .0321) postsurgery, after accounting for pitcher age at surgery.

      Discussion

      In this study, there was no change in velocity or movement in the curve or slider after UCLR when compared with each pitcher’s baseline before surgery in either time frame. After UCLR, the fastball had a statistically significant decrease in upward movement compared with a baseline 24 to 36 months postoperatively. The velocity and horizontal movement of the fastball was unchanged following UCLR in both time frames.
      When considering the pitcher age at surgery, the 26- to 31-year-old group experienced a significant decrease in 4-seam fastball velocity. It is possible this decrease is due to normal aging patterns. UCLR does affect the pitch movement for the 4-seam fastball, and this change does not appear to be due to age-related deterioration, as the pitchers who underwent surgery before 26 years of age were the most severely affected. This group of pitchers lost on average ∼1 inch of 4-seam fastball horizontal movement in both postoperative time frames. In addition, pitchers in the older age groups displayed a significant decrease in vertical movement of their 4-seam fastball in the 24- to 36-month postoperative time frame.
      Four-seam fastball movement derives from the magnitude of backspin placed on the ball by the pitcher, manifesting as horizontal movement and/or vertical movement depending on the orientation of the ball upon release. Variations of wrist and arm angle upon release are strongly correlated with the type of movement seen, whether more horizontal or more vertical.
      • Jinji T.
      • Sakurai S.
      • Hirano Y.
      Factors determining the spin axis of a pitched fastball in baseball.
      The decreases in horizontal and vertical movement in the 4-seam fastball possibly derive from the loss of backspin exerted on the ball upon release. Improved technology has enhanced pitch tracking of MLB pitchers to include additional information such as spin rate and spin axis. Future studies could explore these tools to better understand how pitch characteristics are affected by injuries and surgery.
      Wrist flexor–pronator muscle weakness is a potential mechanistic explanation for the effect of UCLR on backspinches Combined flexor–pronator injury along with ulnar collateral ligament tear has previously been associated with poor outcomes.
      • Osbahr D.C.
      • Swaminathan S.S.
      • Allen A.A.
      • Dines J.S.
      • Coleman S.H.
      • Altchek D.W.
      Combined flexor–pronator mass and ulnar collateral ligament injuries in the elbows of older baseball players.
      In addition, the intimate association of the flexor–pronator mass with the ulnar nerve leads to a significant amount of manipulation of the muscle during transposition of the ulnar nerve.
      • Andrews J.R.
      • Jost P.W.
      • Cain E.L.
      The ulnar collateral ligament procedure revisited: The procedure we use.
      It is possible such manipulation leads to weakness in the flexor–pronator mass that has not previously been detected. Alternatively, differences in UCL tension preoperatively and graft tension postoperatively may lead to a difference in the ability to exert backspin, leading to the differences seen. The difference in 4-seam fastball movement is unlikely to derive from differences in overall mechanics preoperatively and postoperatively as a biomechanical study in active minor league baseball pitchers showed no differences between pitchers with a history of UCLR and those with no history of UCLR.
      • Fleisig G.S.
      • Leddon C.E.
      • Laughlin W.A.
      • et al.
      Biomechanical performance of baseball pitchers with a history of ulnar collateral ligament reconstruction.

      Limitations

      As with all studies, this investigation has limitations. This study only included pitchers who returned to throw at least 20 pitches during a 12- to 24-month and 24- to 36-month time frame after surgery. A substantial portion of pitchers in the PITCHf/x database were excluded, many due to a lack of return to play at the MLB level, delayed return to play leading to insufficient data in the 12- to 24-month postoperative time frame, or transient return to play leading to insufficient data in the 24- to 36-month postoperative time frame. As such, selection bias may be introduced in this study. In addition, the operative methods, individual clinical findings, or surgeon may be influencing results; however, this information is not consistently available so could not be considered or analyzed. Finally, these results may not be generalizable to all professional or amateur pitchers as only those who returned to play within a defined period after UCLR were included. As a result, these results are likely the “best” overall results and may not reflect average anticipated results of UCLR.

      Conclusions

      Following UCLR, MLB pitchers experienced no changes in horizontal or vertical movement or velocity of the curve or slider in either time frame. Decreased upward vertical movement of the fastball occurred after UCLR at final follow-up, but no change was observed in velocity. Similar trends in pitch movement and velocity effects were observed regardless of age.

      Appendix

      Figure thumbnail fx1
      Appendix Fig 1Profile plot displaying the movement trends for each individual pitcher across all time frames.
      Appendix Table 1Descriptive Statistics for Age and Outcome Measures
      VariableTimeNMean(SD)Change

      From Baseline
      (SD)
      Age4627.98(3.58)
      Four-seam fastball velocityBaseline4093.19(2.40)
      Postoperative 14092.7(2.44)–0.49(1.92)
      Postoperative 24092.95(2.25)–0.24(1.48)
      Four-seam fastball HmovBaseline40–5.34(1.48)
      Postoperative 140–4.79(2.44)0.56(2.1)
      Postoperative 240–4.99(1.79)0.35(1.28)
      Four-seam fastball VmovBaseline409.46(1.41)
      Postoperative 1408.98(1.95)–0.48(1.48)
      Postoperative 2409.14(1.39)–0.32(0.92)
      Curveball velocityBaseline2978.87(2.99)
      Postoperative 12979.26(2.93)0.39(1.4)
      Postoperative 22979.2(2.92)0.33(1.66)
      Curveball HmovBaseline295.16(2.10)
      Postoperative 1295.07(2.27)–0.09(1.22)
      Postoperative 2295.14(2.30)–0.01(1.45)
      Curveball VmovBaseline29–5.47(2.15)
      Postoperative 129–5.59(2.49)–0.12(1.65)
      Postoperative 229–5.59(2.51)–0.13(2.09)
      Slider VelocityBaseline2684.75(2.45)
      Postoperative 12684.52(2.68)–0.23(1.92)
      Postoperative 22684.46(2.56)–0.29(1.5)
      Slider HmovBaseline261.87(2.15)
      Postoperative 1261.63(1.84)–0.24(1.35)
      Postoperative 2261.53(2.26)–0.34(1.45)
      Slider VmovBaseline261.44(2.07)
      Postoperative 1261.69(3.10)0.25(2.03)
      Postoperative 2261.14(2.82)–0.3(1.78)
      Hmov, horizontal movement; SD, standard deviation; Vmov, vertical movement.
      Appendix Table 2Final Model (Correlation Structure) for Each Movement Measure, by Pitch Type, Showing Significant Differences in Four-Seam Fastball Metrics and No Significant Differences in Curve or Slider Metrics
      VariableEffectEstimateSEt ValueP value
      Four-seam fastball velocityIntercept94.492.6735.39<.0001
      (CS)Age–0.050.09–0.49.6267
      Postoperative 1–0.490.27–1.81.0749
      Postoperative 2–0.240.27–0.89.3761
      Four-seam fastball HmovIntercept–6.411.9–3.36.0018
      (UN)Age0.040.070.56.5776
      Postoperative 10.560.331.67.1024
      Postoperative 20.350.21.72.0925
      Four-seam fastball VmovIntercept11.221.76.59<.0001
      (UN)Age–0.060.06–1.04.3036
      Postoperative 1–0.480.23–2.05.0475
      Postoperative 2–0.320.15–2.22.0321
      Curveball velocityIntercept80.934.219.29<.0001
      (CS)Age–0.080.15–0.5.6230
      Postoperative 10.390.271.49.1429
      Postoperative 20.330.271.25.2181
      Curveball HmovIntercept3.63.251.11.2780
      (UN)Age0.060.120.48.6338
      Postoperative 1–0.090.23–0.38.7038
      Postoperative 2–0.010.27–0.04.9677
      Curveball VmovIntercept–5.073.19–1.59.1238
      (UN)Age–0.010.12–0.13.9006
      Postoperative 1–0.120.31–0.4.6953
      Postoperative 2–0.130.39–0.33.7432
      Slider velocityIntercept82.413.6922.33<.0001
      (AR(1))Age0.080.130.64.5277
      Postoperative 1–0.230.41–0.55.5843
      Postoperative 2–0.290.31–0.96.3425
      Slider HmovIntercept2.083.010.69.4974
      (UN)Age–0.010.11–0.07.9453
      Postoperative 1–0.240.27–0.9.3786
      Postoperative 2–0.340.29–1.2.2402
      Slider VmovIntercept-1.813.43–0.53.6021
      (UN)Age0.120.120.95.3496
      Postoperative 10.250.40.63.5334
      Postoperative 2–0.30.35–0.86.3959
      NOTE. P values in bold are statistically significant.
      CS, compound symmetry; Hmov, horizontal movement; SE, standard error; UN, unstructured; Vmov, vertical movement.

      Supplementary Data

      References

        • Conte S.A.
        • Fleisig G.S.
        • Dines J.S.
        • et al.
        Prevalence of ulnar collateral ligament surgery in professional baseball players.
        Am J Sports Med. 2015; 43: 1764-1769
        • Mahure S.A.
        • Mollon B.
        • Shamah S.D.
        • Kwon Y.W.
        • Rokito A.S.
        Disproportionate trends in ulnar collateral ligament reconstruction: Projections through 2025 and a literature review.
        J Shoulder Elbow Surg. 2016; 25: 1005-1012
        • Cain E.L.
        • McGonigle O.
        Return to play following ulnar collateral ligament reconstruction.
        Clin Sports Med. 2016; 35: 577-595
        • Ford G.M.
        • Genuario J.
        • Kinkartz J.
        • Githens T.
        • Noonan T.
        Return-to-play outcomes in professional baseball players after medial ulnar collateral ligament injuries: Comparison of operative versus nonoperative treatment based on magnetic resonance imaging findings.
        Am J Sports Med. 2016; 44: 723-728
        • Griffith T.B.
        • Duralde X.A.
        Successful performance after ulnar collateral ligament reconstruction: An analysis of 88 drafted professional baseball pitchers with a matched comparison cohort.
        Orthop J Sports Med. 2019; 72325967119880820
        • Jiang J.J.
        • Leland J.M.
        Analysis of pitching velocity in major league baseball players before and after ulnar collateral ligament reconstruction.
        Am J Sports Med. 2014; 42: 880-885
        • Keller R.A.
        • Marshall N.E.
        • Guest J.-M.
        • Okoroha K.R.
        • Jung E.K.
        • Moutzouros V.
        Major League Baseball pitch velocity and pitch type associated with risk of ulnar collateral ligament injury.
        J Shoulder Elbow Surg. 2016; 25: 671-675
        • Lansdown D.A.
        • Feeley B.T.
        The effect of ulnar collateral ligament reconstruction on pitch velocity in major league baseball pitchers.
        Orthop J Sports Med. 2014; 22325967114522592
        • Makhni E.C.
        • Lee R.W.
        • Morrow Z.S.
        • Gualtieri A.P.
        • Gorroochurn P.
        • Ahmad C.S.
        Performance, return to competition, and reinjury after Tommy John surgery in major league baseball pitchers: A review of 147 cases.
        Am J Sports Med. 2014; 42: 1323-1332
        • Swindell H.W.
        • Trofa D.P.
        • Confino J.
        • Sonnenfeld J.J.
        • Alexander F.J.
        • Ahmad C.S.
        Performance in collegiate-level baseball players after elbow ulnar collateral ligament reconstruction.
        Orthop J Sports Med. 2020; 82325967120913013
        • BrooksBaseball.net
        Home of the PITCHf/x Tool.
        (. Accessed June 23, 2021)
      1. Pitch Info: Pitch Classifications, Data Management, Consulting.
        (. Accessed June 23, 2021)
      2. Spin Rate Part II: Spin Axis & Useful Spinches Driveline Baseball. Published November 28, 2016. Accessed June 23, 2021. https://www.drivelinebaseball.com/2016/11/spin-rate-part-ii-spin-axis-useful-spin/

      3. TJ Surgery: AllTime MLB List. MLB Reports. Published April 21, 2012. Accessed June 23, 2021. https://mlbreports.com/tj-surgery/

        • Smith R.
        • Lombardo D.J.
        • Petersen-Fitts G.R.
        • et al.
        Return to play and prior performance in Major League Baseball pitchers after repair of superior labral anterior-posterior tears.
        Orthop J Sports Med. 2016; 42325967116675822
        • Wilson A.T.
        • Pidgeon T.S.
        • Morrell N.T.
        • DaSilva M.F.
        Trends in revision elbow ulnar collateral ligament reconstruction in professional baseball pitchers.
        J Hand Surg Am. 2015; 40: 2249-2254
        • Jinji T.
        • Sakurai S.
        • Hirano Y.
        Factors determining the spin axis of a pitched fastball in baseball.
        J Sports Sci. 2011; 29: 761-767
        • Osbahr D.C.
        • Swaminathan S.S.
        • Allen A.A.
        • Dines J.S.
        • Coleman S.H.
        • Altchek D.W.
        Combined flexor–pronator mass and ulnar collateral ligament injuries in the elbows of older baseball players.
        Am J Sports Med. 2010; 38: 733-739
        • Andrews J.R.
        • Jost P.W.
        • Cain E.L.
        The ulnar collateral ligament procedure revisited: The procedure we use.
        Sports Health. 2012; 4: 438-441
        • Fleisig G.S.
        • Leddon C.E.
        • Laughlin W.A.
        • et al.
        Biomechanical performance of baseball pitchers with a history of ulnar collateral ligament reconstruction.
        Am J Sports Med. 2015; 43: 1045-1050