Total Pitch Research Articles

Analysis and multi-response optimization of gear quality and surface finish of meso-sized helical and bevel gears manufactured by WSEM process

This paper studies influence of and optimizes pulse-on time, pulse-off time, servo voltage, and feed rate of wire on microgeometry and surface finish of stainless steel meso-helical gears (MHG) and meso-bevel gears (MBG) manufactured by wire spark erosion machining (WSEM) process. Microgeometry of MHG was evaluated in terms of error in total profile and total cumulative pitch and that of MBG in terms of error in single pitch and total cumulative pitch. Average and maximum surface roughness values were used to evaluate their surface finish. Twenty-nine experiments with two replicates were conducted using Box-Behnken approach of response surface methodology thus manufacturing 58 meso-helical gears and 58 meso-bevel gears. It was observed that higher pulse-on time and servo voltage, and lower pulse-off time and feed rate of wire yield poor microgeometry and surface finish of MHG and MBG. Desirability function analysis based multi-response optimization was used to identify optimum WSEM parameters to manufacture the best quality of MHG and MBG. The optimized values of the responses were validated experimentally. It was found that WSEM can attain up to DIN 6 quality in microgeometry of MHG and MBG. SEM micrographs of the best quality MHG and MBG revealed accurate and uniform bore, tooth profile, flank surfaces free from burrs and sharp edges and without any undercut at root. Microstructural examination of these gears showed flank surfaces free from cracks, globules and pores. This study proves that WSEM is economical and technically superior process for near net-shape manufacturing of high quality MHG and MBG.

Unsteady RANSE simulation for ship resistance, heave and pitch in regular head waves

This study presents an attempt to perform a viscous numerical simulation for ship advancing in regular head waves. The simulation includes computations for total ship resistance, heave and pitch responses for the bare hull of the US Navy combatant DTMB 5512 ship model. The computations are carried out by making use of the commercial software Fine™/Marine provided by NUMECA, where the discretization in space is based on finite volume method using unstructured grid. The unsteady Reynolds-Averaged Navier-Stokes equation is solved while the turbulence is modelled by making use of k-ω shear stress transport model. The free-surface is solved based on volume of fluid method. Results are obtained for ship resistance coefficient, heave and pitch and compared with experimental results provided in the Gothenburg 2010 Workshop on the Naval Hydrodynamics. The comparison of the computed results showed an encouraging agreement with the measured results. Finally, a special investigation for the added resistance in waves is made by comparing the results obtained in this computation with other results obtained in calm water.

Release Location in a Risk Factor for Ulnar Collateral Ligament Reconstruction in Major League Baseball Pitchers

Objectives:Medial ulnar collateral ligament reconstruction (UCLR) is a common procedure performed for Major League Baseball (MLB) pitchers. The etiology of UCL injury is complex and not entirely understood. The purpose of this study was to use publically available pitch tracking technology (PITCHf/x) to compare the pre-injury throwing mechanics of MLB pitchers who require UCL reconstructive surgery with those of pitchers who have never undergone UCL reconstruction.Methods:Pitch tracking and demographic data on MLB pitchers who had undergone UCL reconstruction between the 2010 and 2017 seasons was gathered. Pitchers were excluded if they did not throw 100 total pitches in each of the three years prior to surgery. Furthermore, only pitch types that a given pitcher utilized more than 25 times in each of the three years prior to surgery were included for individual analysis. Pitch type, release location, and velocity were compared between the UCL reconstructive surgery cohort and a matched-control cohort.Results:The average pitch release location for pitchers who required UCL reconstruction was more lateral in the two years immediately preceding surgery than the control cohort (p=0.001 and p=0.023). Furthermore, a time-based comparison between the year immediately preceding surgery and two years prior showed a more lateral release immediately prior to surgery (p=0.036). Pitchers who required UCL reconstruction throw similar rates of fastballs as the control cohort and the average pitch velocity and fastball velocity were similar between the UCL group and the control group. The control pitchers displayed a significant decrease in average pitch velocity (p=0.005) and average fastball velocity (p=0.012) over the period of the study.Conclusion:Pitch tracking indicates pitch selection and pitch velocity are similar before that the average release point is more lateral preceding UCL reconstruction as compared to the control cohort suggesting that pitch release location might be an independent risk factor for UCL injury and reconstruction. On the other hand, pitch selection and pitch velocity are similar between these cohorts. Powerful technology including PITCHf/x allows for accurate monitoring of factors such as arm position and could potentially be used to identify pitchers at risk for UCL rupture.Figure 1Average pitch release location with error bars for standard eror of the mean. Location is measured as feet from the center of the mound, and left-handed pitchers are normalized to the right handed pitcher. UCL pitchers (dark grey) have a significantly more lateral and lower release locations in Year I (the year immediately prior to surgery) than did the control group (light grey). Furthrmore, the release location of UCL pitchers is more lateral in the Year I than in Year III.

How many innings can we throw: does workload influence injury risk in Major League Baseball? An analysis of professional starting pitchers between 2010 and 2015

There has been increasing interest regarding the association between pitch counts, as well as total workload per season, and the risk of injury among Major League Baseball (MLB) starting pitchers. We used publicly available databases to identify all MLB starting pitchers eligible for play who made at least 5 starts in seasons between 2010 and 2015. For all included pitchers, annual pitching statistics (number of starts, total season pitch counts, total season inning counts, and average pitch count per game started) and annual disabled list (DL) information (time on DL for any reason and time on DL related to upper extremity, lower extremity, or axial body injury) were collected. A multiple logistic regression analyzed games started, pitch counts, innings pitched, and pitches per start during all previous seasons as a risk factor for injury in the current season, controlling for previous injury. A total of 161 starting MLB pitchers met the inclusion criteria. With the exception of total innings pitched from 2010-2011 being significantly associated with DL placement in 2012 (no DL, 310.5 ± 97.5 innings; DL, 344.7 ± 85.9 innings; P = .040), no other finding for starts, pitch counts, innings, or pitches per start in the cumulative years from 2010-2014 had a significant association with pitcher placement on the DL for any musculoskeletal reason or for an upper extremity reason between 2011 and 2015. In this study, we demonstrate that there is no association between preceding years of cumulative pitches, starts, innings pitched, or average pitches per start and being placed on the DL for any musculoskeletal reason.

Unaccounted Workload Factor: Game-Day Pitch Counts in High School Baseball Pitchers-An Observational Study.

Background:Throwing injuries are common in high school baseball. Known risk factors include excessive pitch counts, year-round pitching, and pitching with arm pain and fatigue. Despite the evidence, the prevalence of pitching injuries among high school players has not decreased. One possibility to explain this pattern is that players accumulate unaccounted pitch volume during warm-up and bullpen activity, but this has not yet been examined.Hypotheses:Our primary hypothesis was that approximately 30% to 40% of pitches thrown off a mound by high school pitchers during a game-day outing are unaccounted for in current data but will be revealed when bullpen sessions and warm-up pitches are included. Our secondary hypothesis was that there is wide variability among players in the number of bullpen pitches thrown per outing.Study Design:Cross-sectional study; Level of evidence, 3.Methods:Researchers counted all pitches thrown off a mound during varsity high school baseball games played by 34 high schools in North Central Florida during the 2017 season.Results:We recorded 13,769 total pitches during 115 varsity high school baseball starting pitcher outings. The mean ± SD pitch numbers per game were calculated for bullpen activity (27.2 ± 9.4), warm-up (23.6 ±8.0), live games (68.9 ±19.7), and total pitches per game (119.7 ± 27.8). Thus, 42.4% of the pitches performed were not accounted for in the pitch count monitoring of these players. The number of bullpen pitches thrown varied widely among players, with 25% of participants in our data set throwing fewer than 22 pitches and 25% throwing more than 33 pitches per outing.Conclusion:In high school baseball players, pitch count monitoring does not account for the substantial volume of pitching that occurs during warm-up and bullpen activity during the playing season. These extra pitches should be closely monitored to help mitigate the risk of overuse injury.

The role of positional knowledge and tonal approaches in cellists’ sight-reading

Sight-reading is an important skill for amateur and professional musicians. Several factors seem to play a role in sight-reading skills, such as expertise level, ear training, mental speed and improvisation skills. If we are right in supposing that these factors cannot easily be generalized for all musicians, one of the reasons for this must surely lie in the fact that different musical instruments set different technical requirements for the player. The purpose of this study was to investigate which factors help cello students have better sight-reading abilities. Amateur cello students ( N = 79) were tested for position knowledge, use of tonal and positional approaches and actual sight-reading ability, and their sight-reading performance was measured by counting pitch and fluency errors they made in short pieces of varying complexity. This study used a partly correlational (use of tonal/positional approaches, technical level, experience, and position knowledge) and a partly experimental repeated-measures design (key complexity). The findings suggest that position knowledge shows a very strong negative correlation with the number of sight-reading errors and a weak correlation with pauses. Use of positional approaches shows no significantly stronger correlation with the number of sight-reading errors than the use of tonal approaches. In addition, it appears that an increase in the key complexity leads to more sight-reading errors and more pauses. Finally, the position knowledge and technical level of participants explain 83% of the variation in the total pitch errors. Experience and use of tonal approaches explain 40% of the variation in the number of short pauses.

Exploring WSEM Process for Manufacturing Meso Helical and Bevel Gears

This paper presents an experimental investigation with objective to explore and establish WSEM (wire spark-erosion machining) process as a technically superior alternative for manufacturing the best quality and closed to net-shape meso helical gear (MHG) and meso bevel gear (MBG) made of stainless steel (SS 304). Effect of variable WSEM parameters namely servo voltage ‘SV’, pulse-on-time ‘Ton’, peak current ‘IP’, pulse-off time ‘Toff’, feed rate of wire ‘WF’, wire tension ‘WT’, dielectric flow rate ‘WP’ and percentage cutting speed ‘CS’ on gear cutting rate (GCR) and average surface roughness (Ra) are studied. The experiments were planned and designed according to one-variable-at-time approach of ‘Design of Experiments’ to determine the variation in gear cutting rate and average surface roughness with WSEM process parameters. It was observed that servo voltage, pulse-on-time and peak current significantly affect the GCR and Ra. Gear quality standard up to DIN quality number 7 for error in single and error in total pitch of MBG; and DIN quality number 7 and 6 for error in total profile and error in total pitch respectively of MHG were achieved by WSEM process. This study explores capabilities and superiority of WSEM to manufacture closed to net-shape MHG and MBG.

Schottky Tunneling Effects in a Tunnel FET

Tunnel FETs (TFETs) have attracted a great deal of attention due to their steep subthreshold swing (SS) of less than 60 mV/dec, which overcomes the theoretical constraint imposed by the thermal limit in a conventional inversion-mode (IM) FET. Based on its advantages as a short-channel device with low stand-by power consumption, TFETs shows promise to replace IM-FETs. As the channel length is shortened to minimize the total gate pitch; however, the gate sidewall spacer is miniaturized as well. In this paper, the influence of junction extension length ( $L_{\mathrm {ext}})$ on TFET behavior is discussed where the length of the gate spacer is assumed to be the gap between the source and drain (S/D) electrodes and the gate edge. It was found that, when $L_{\mathrm {ext}}$ is aggressively scaled down, having S/D electrodes (silicide or metal) with identical work functions (WFs) leads to a severely high OFF-current ( $I_{ \mathrm{\scriptscriptstyle OFF}})$ and high SS. By adopting separate asymmetric WFs for the p-type and n-type S/D electrodes, the on/off characteristics were improved with suppressed $I_{ \mathrm{\scriptscriptstyle OFF}}$ and steeper slopes. It was also shown that the device performance of a TFET with higher source-side doping concentrations ( $\sim 5\times 10^{20}$ cm−3) can be further improved even at the aggressively scaled-down $L_{\mathrm {ext}}$ by boosting the on-current.

Improving spur gear microgeometry and surface finish by AFF process

ABSTRACTThis paper describes improving microgeometry and surface finish of spur gears by abrasive flow finishing (AFF) by experimentally identifying optimum values of finishing time and AFF medium viscosity. An experimental apparatus was developed for gear finishing by AFF using a medium of silicon carbide as abrasives, silly putty and silicone oil as blending agents. A special fixture was developed comprising of two metalon cylindrical disks having circumferential holes for back and forth movements of AFF medium between two adjacent flanks of 20MnCr5 alloy steel spur gear teeth. Twenty experiments were conducted varying AFF medium viscosity at four levels and finishing time at five levels to study their influence on error reduction in total profile, total lead, total pitch, runout, and average surface roughness. Results showed considerable reduction in the microgeometry deviation and surface roughness with AFF medium viscosity increase and existence of optimum finishing time for attaining maximum improvement in microgeometry and surface finish. Consequently, 25 min and 135 kPa. s were identified as optimum values and corresponding gear’s microgeometry and microstructure were studied. It revealed that AFF-finished gear flank surfaces are free from cracks, cutter marks, thermal distortions. This proves AFF as economical and productive alternative for gear finishing.

Acoustic features of vocalization as a tool for estrus detection in Murrah buffaloes

Twelve Murrah buffaloes were selected from the institute herd and acoustic features like call duration, amplitude, total energy, mean pitch, mean intensity, formants (F1, F2, F3, F4, and F5), and N/H (Noise to Harmonic) ratio were analyzed. Call duration was significantly higher on day of estrus (1.52 ± 0.07 s) and proestrus (1.44 ± 0.07 s) than in metestrus (1.241 ± 0.04 s) and diestrus stages (0.981 ± 0.05 s). Total energy (0.121 ± 0.01 P2s), mean pitch (226.67 ± 14.11 Hz), maximum amplitude (0.959 ± 0.01 P), and mean intensity (85.05 ± 0.26 dB) was more (p < 0.05) in proestrus than in other stages. F1 (1131.94 ± 11.85 Hz) and F5 formants (6567.74 ± 12.62 Hz) were significantly higher (p < 0.05) during estrus, while F2 (2238.46 ± 26.53 Hz), F3 (3435.00 ± 19.33 Hz), and F4 formants (5127.71 ± 25.90 Hz) were higher (p < 0.05) in proestrus in comparison to other stages of estrous cycle. The identified acoustic features of voice in Murrah buffaloes were signficantly different in various stages of estrous cycle. These could be used as a tool for estrus detection management in buffaloes which have probems of silent estrus.

Investigations on microgeometry of meso bevel and meso helical gears manufactured by WEDM process

This article reports about investigations on microgeometry of meso bevel and meso helical gears manufactured by wire electro discharge machining (WEDM) process. Effects of eight WEDM parameters (namely, peak current, pulse-on time, pulse-off time, servo-gap voltage, wire feed rate, wire tension, dielectric pressure and percentage cutting speed) on single pitch error and total pitch error for meso bevel gear and total profile error and total pitch error for meso helical gear were studied. A total of 31 experiments for meso bevel gear and 31 experiments for meso helical gears were conducted using one-factor-at-time approach to identify optimum ranges/values of the eight WEDM parameters for further experiments. It revealed existence of optimum ranges of servo-gap voltage, pulse-on time, pulse-off time, and percentage of the cutting speed to minimize microgeometry errors in meso bevel and helical gears and that use of higher values of peak current, wire feed rate, wire tension, and dielectric pressure yields better quality of meso bevel and helical gears. The best quality meso helical gear has better quality (DIN 6, DIN 6, and DIN 8) than the best quality meso bevel gear (DIN 7, DIN 7, and DIN 10) for single pitch error, total pitch error, and radial runout; whereas for successive pitch error, reverse is true. Meso helical gear has better surface finish (R a 1.1 μm and R max 7.3 μm) than meso bevel gear (R a 1.3 μm and R max 8.0 μm). Examination of tooth profiles of the best quality meso gears by scanning electron microscopy revealed that they have uniform tooth profiles that are free from burrs, nicks, asperities, dimples, undercutting at the root, and sharp edges on both end faces of the gears. It also revealed that tooth flank surfaces are free from micro-cracks, pores, and globules. The present work proves that WEDM has potential to be a better alternative for manufacturing better quality net-shaped meso bevel and helical gears which will not require any further post-manufacturing processing.

P‐79: Substrate Glass Evaluation for New PLAS TFT Technology

Generation 10 substrate glasses were evaluated to determine the performance impact on the newly developed partial laser annealed silicon (PLAS) TFT technology. We found that substrates with higher annealing point and Young's Modulus reduce total pitch (TP) and warp in this process and only slightly reduce total pitch variation (TP).

The Effect Of Between Innings Cooling Or Compression On Baseball Pitching During Competitive Game

In baseball, pitching effectiveness is critical for team success. Previous research has identified that short-duration cooling in between simulated innings was effective for maintaining velocity and improved perceptions of recovery. This combination is thought to improve overall pitching effectiveness. PURPOSE: A pilot study to assess the effect of short-term, between innings, cryotherapy and/or compression on perceived exertion and recovery of pitchers during a live college baseball game. METHODS: NCAA Division II baseball pitchers were studied during Fall season scrimmages. Participants were familiarized with the Rating of Perceived Exertion (RPE) and Perceived Recovery Scale (PRS) prior to game play. Participants dressed in game day attire and warmed up in their usual manner. After each inning, RPE was recorded upon entering the dugout. Between innings, participants received one of two treatments: 1) cryotherapy and compression or 2) compression alone (of the equal weight to the cryotherapy and compression) applied to his shoulder and elbow for four minutes, regardless of the length of time between innings (unless this time was less than four minutes). Each pitcher indicated his PRS before re-entering the game to pitch. Time of each inning pitched from warm up pitch to last pitch, rest time, and total pitches thrown were recorded. RPE was measured following the final inning pitched as well as 3 days later prior to throwing the next bullpen. Repeated measures ANOVA were used to determine if RPE or PRS were significantly different between innings. RESULTS: Five players participated. One player was excluded because he did not pitch more than one inning. There were no significant differences between RPE or PRS between treatment conditions. Individual RPE values remained constant or declined in subsequent innings with treatment in four of the five players. PRS improved in subsequent innings during the cold treatment. CONCLUSIONS: Sample size was likely too small to detect differences. This pilot study may indicate that with more subjects and/or innings pitched, cold and/or compression could be effective modalities for improving perceived exertion and recovery during a collegiate game. Further studies need to be conducted during the competitive season to include a greater number of players and innings pitched.

Applications of computer vision in measuring total cumulative pitch deviation of a gear

Applications of computer vision in measuring total cumulative pitch deviation of a gear

Scaling carbon nanotube complementary transistors to 5-nm gate lengths.

High-performance top-gated carbon nanotube field-effect transistors (CNT FETs) with a gate length of 5 nanometers can be fabricated that perform better than silicon complementary metal-oxide semiconductor (CMOS) FETs at the same scale. A scaling trend study revealed that the scaled CNT-based devices, which use graphene contacts, can operate much faster and at much lower supply voltage (0.4 versus 0.7 volts) and with much smaller subthreshold slope (typically 73 millivolts per decade). The 5-nanometer CNT FETs approached the quantum limit of FETs by using only one electron per switching operation. In addition, the contact length of the CNT CMOS devices was also scaled down to 25 nanometers, and a CMOS inverter with a total pitch size of 240 nanometers was also demonstrated.

Major League pitching workload after primary ulnar collateral ligament reconstruction and risk for revision surgery

Literature has attempted to correlate pitching workload with risk of ulnar collateral ligament (UCL) injury; however, limited data are available in evaluating workload and its relationship with the need for revision reconstruction in Major League Baseball (MLB) pitchers. We identified 29 MLB pitchers who underwent primary UCL reconstruction surgery and subsequently required revision reconstruction and compared them with 121 MLB pitchers who underwent primary reconstruction but did not later require revision surgery. Games pitched, pitch counts, and innings pitched were evaluated and compared for the seasons after returning from primary reconstruction and for the last season pitched before undergoing revision surgery. The difference in workload between pitchers who did and did not require revision reconstruction was not statistically significant in games pitched, innings pitched, and MLB-only pitch counts. The one significant difference in workload was in total pitch counts (combined MLB and minor league), with the pitchers who required revision surgery pitching less than those who did not (primary: 1413.6 pitches vs. revision: 959.0 pitches, P = .04). In addition, pitchers who required revision surgery underwent primary reconstruction at an early age (22.9 years vs. 27.3 years, P < .001) and had less MLB experience (1.5 years vs. 5.0 years, P < .001). There is no specific number of pitches, innings, or games that place a pitcher at an increase risk for injury after primary UCL reconstruction. However, correlations of risk may be younger age and less MLB experience at the time of the primary reconstruction.

Should We Limit Innings Pitched After Ulnar Collateral Ligament Reconstruction in Major League Baseball Pitchers?

Background: Ulnar collateral ligament reconstruction (UCLR) has become a common procedure among Major League Baseball (MLB) pitchers. It is unclear if a limit on innings pitched after UCLR should be instituted to prevent revision UCLR. Hypothesis: Number of innings pitched and number of pitches thrown after UCLR will not affect whether a pitcher requires a revision UCLR. Study Design: Descriptive laboratory study. Methods: All MLB pitchers between 1974 and 2015 who pitched at least 1 full season after UCLR were included in this study. Pitch counts and innings pitched for the first full season after UCLR as well as total pitch count and total innings pitched were recorded. Pitch counts and innings pitched were compared among players who required revision UCLR and those who did not. Results: Overall, 154 pitchers were included. Of these, 135 pitchers did not require revision UCLR while 19 underwent revision UCLR. No significant difference existed between pitchers who underwent revision UCLR and those who did not when comparing number of innings pitched in the season after UCLR (79.4 ± 46.7 vs 90.1 ± 58.6; P = .9016), number of pitches thrown in the season after UCLR (1233.2 ± 710.4 vs 1449.2 ± 904.1; P = .7337), number of innings pitched in the pitcher’s career after UCLR (357.4 ± 312.0 vs 399.3 ± 446.4; P = .6945), and number of pitches thrown in the pitcher’s career after UCLR (5632.7 ± 4583.9 vs 5674.7 ± 5755.4; P = .4789), respectively. Furthermore, no difference existed in revision rate between pitchers who pitched more or less than 180 innings in the first full season after UCLR (P = .6678). Conclusion: The number of innings pitched and number of pitches thrown in the first full season as well as over a player’s career after UCLR are not associated with an increased risk of a pitcher requiring revision UCLR.

Should We Limit Innings Pitched Following Ulnar Collateral Ligament Reconstruction in Major League Baseball Pitchers?

Objectives:Background: Ulnar collateral ligament reconstruction (UCLR) has become a common procedure amongst major league baseball (MLB) pitchers. It is unclear if a limit on innings pitched following UCLR should be instituted to prevent revision UCLR.Purpose:To determine whether the number of innings pitched or number of pitches thrown in the first full season following UCLR, as well as the pitcher’s overall MLB career, correlated with need for a revision UCLRHypothesis:Number of innings pitched and number of pitches thrown following UCLR will not affect whether a pitcher undergoes a revision UCLR.Methods:Methods: All MLB pitchers between 1974-2015 who pitched at least one full season following UCLR were included. Pitch counts and innings pitched for the first full season following UCLR as well as total pitch count and total innings pitched following UCLR were recorded. Pitch counts and innings pitched were compared amongst players who required revision UCLR and those who did not.Results:Results: Overall, 154 pitchers were included. Of these, 135 pitchers did not require revision UCLR while 19 underwent revision UCLR. No significant difference existed between pitchers who underwent revision UCLR and those who did not in: number of innings pitched in the season following UCLR (p=0.9016), number of pitches thrown in the season following UCLR (p=0.7337), number of innings pitched in the pitcher’s career following UCLR (p=0.6945), and number of pitches thrown in the pitcher’s career following UCLR (p=0.4789). Furthermore, no difference existed in revision rate between pitchers who pitched more or less than 180 innings in the first full season following UCLR (p=0.6678).Conclusion:Conclusion: The number of innings pitched and number of pitches thrown in the first full season as well as over a player’s career following UCLR does not appear to increase a player’s risk of revision UCLR.

Outcomes in Revision Tommy John Surgery in Major League Baseball Pitchers

Background With the recent rise in the number of Tommy John surgeries, a proportionate rise in revisions is expected. However, much is unknown regarding the current revision rate of Tommy John surgery, return to play, and change in performance in Major League Baseball (MLB) pitchers. Methods Publicly available databases were used to obtain a list of all MLB pitchers who underwent primary and revision Tommy John surgery. Pitching performance preoperatively and postoperatively for pitchers who returned to 1 or more MLB games after revision surgery was compared with controls matched for age and position. Results Since 1999, 235 MLB pitchers have undergone Tommy John surgeries; 31 pitchers (13.2%) underwent revision surgery, and 37% underwent revision within 3 years of the index procedure. Twenty-six revisions had more than 2 years of follow-up; 17 pitchers (65.4%) returned to pitch at least 1 major league game, whereas only 11 (42.3%) returned to pitch 10 or more games. Of those who returned to MLB competition, the average length of recovery was 20.76 months. Compared with controls matched for age and position, MLB pitchers undergoing revision surgery had a statistically shorter career after revision surgery (4.9 vs 2.6 seasons, P = .002), pitched fewer innings, and had fewer total pitches per season. Conclusions The rate of revision Tommy John surgery is substantially higher than previously reported. For MLB pitchers, return to play after revision surgery is much lower than after primary reconstruction. The overall durability of MLB pitchers after revision ulnar collateral ligament reconstruction decreases significantly compared with controls matched for age and matched controls.

Pitch Characteristics Before Ulnar Collateral Ligament Reconstruction in Major League Pitchers Compared With Age-Matched Controls.

Background:Ulnar collateral ligament reconstruction (UCLR) is commonly performed in Major League Baseball (MLB) pitchers, but little is known about the preoperative pitch type and velocity characteristics of pitchers who go on to undergo UCLR.Hypothesis:Pitchers who required UCLR have thrown a greater percentage of fastballs and have greater pitch velocities compared with age-matched controls in the season before injury.Study Design:Case-control study; Level of evidence, 3.Methods:MLB pitchers active during the 2002 to 2015 seasons were included. The UCLR group consisted of MLB pitchers who received UCLR between 2003 and 2015, utilizing the season before surgery (2002-2014) for analysis. The control group comprised age-matched controls of the same season. Players who pitched less than 20 innings in the season before surgery were excluded. Pitch types were recorded as percentage of total pitches thrown. Pitch velocities were recorded for each pitch type. Pitch type and pitch velocities during preoperative seasons for UCLR pitchers were compared with age-matched controls using univariate and multivariate models.Results:A total of 114 cases that went on to UCLR and 3780 controls were included in the study. Pitchers who went on to UCLR appear to have greater fastball, slider, curveball, changeup, and split-fingered fastball velocities; there were no significant differences in pitch selection between the 2 groups.Conclusion:In the season before surgery, MLB pitchers who underwent UCLR demonstrated greater fastball, slider, curveball, changeup, and split-fingered fastball velocities, with no significant difference in pitch type.