ABSTRACT
BACKGROUND: Although contralateral trunk tilt has been recognized, the phenomenon of excessive ipsilateral trunk tilt, often observed during earlier portions of the pitch, has not been explored as a potential correlate with throwing-arm kinetics among baseball pitchers. The purpose of this study was to evaluate kinetic and kinematic parameters among high school and professional pitchers related to excessive ipsilateral and contralateral trunk tilt. METHODS: Professional and high school pitchers were assessed with a 3-dimensional motion capture system (480 Hz) while pitching. Pitchers were grouped as follows: excessive ipsilateral tilt at foot contact (FC), neutral, or excessive contralateral tilt at ball release (BR). Trunk and shoulder kinematics as well as throwing-arm kinetics were compared between subgroups via post hoc regression analysis. RESULTS: Professional pitchers (n = 287) had significantly higher ipsilateral trunk tilt at FC (P < .001) than high school pitchers (n = 59). High school pitchers with excessive contralateral trunk tilt at BR experienced significantly higher shoulder superior force (27.0% ± 7.4% body weight [BW] vs. 17.6% ± 5.1% BW, P < .001) and shoulder anterior force (39.6% ± 8.2% BW vs. 35.7% ± 5.4% BW, P < .001) compared with the ipsilateral trunk tilt cohort but had comparable ball velocity (30.2 ± 3.2 m/s vs. 30.4 ± 2.1 m/s, P = .633). For professionals, for every 10° increase in ipsilateral trunk tilt at FC, ball velocity increased by 0.2 m/s (B = 0.02, ß = 0.07, standard error [SE] = 0.005, P = .010) whereas elbow varus torque decreased by 0.1% BW × height (B = -0.01, ß = -0.08, SE = 0.002, P < .001) and shoulder internal rotation torque decreased by 0.1% BW × height (B = -0.01, ß = -0.07, SE = 0.002, P = .005). CONCLUSION: High school and professional pitchers with excessive ipsilateral trunk tilt at FC consistently demonstrated significantly decreased throwing-arm kinetics (shoulder anterior force and shoulder superior force for high school pitchers and shoulder internal rotation torque and elbow varus torque for professional pitchers) compared with pitchers with excessive contralateral trunk tilt at BR, with equivalent ball velocity. In addition, professional pitchers appeared to engage in significantly greater ipsilateral trunk tilt during early portions of the pitch when compared with high school pitchers, which may represent a kinetically favorable method adopted by pitchers at higher playing levels to maintain adequate ball velocity while concomitantly minimizing throwing-arm kinetics.
Subject(s)
Baseball , Elbow Joint , Shoulder Injuries , Biomechanical Phenomena , Body Weight , Humans , Schools , Upper ExtremityABSTRACT
BACKGROUND AND HYPOTHESIS: Arthroscopic rotator cuff repair surgery is one of the most common shoulder procedures performed in the United States. Although several studies have shown considerable symptomatic relief in the short term following surgery, a relatively high rate of recurrent defects has led surgeons to question the long-term durability of this operation. We hypothesized that outcomes at a minimum of 15 years of follow-up in patients who underwent all-arthroscopic rotator cuff repair would be maintained and would remain significantly improved compared with the preoperative status. METHODS: All-arthroscopic rotator cuff repairs were performed in 193 patients from 2003 to 2005. Patient-reported outcomes were collected preoperatively and at 1, 2, 5, and ≥15 years postoperatively. The primary outcome was the American Shoulder and Elbow Surgeons (ASES) score. Secondary outcomes included Single Assessment Numeric Evaluation (SANE), Shoulder Activity Scale (SAS), visual analog scale, and Patient-Reported Outcomes Measurement Information System (PROMIS)-Upper Extremity (UE) scores. Patient demographic characteristics, revision surgical procedures, and complications were recorded. Generalized estimating equations were used to model scores over time, and multiple comparisons between time points were performed using Tukey adjustment. RESULTS: This study included 60 patients with a mean follow-up period of 16.5 years (range, 15.8-17.7 years). The mean ASES score improved from 60.2 ± 18.8 preoperatively to 93.0 ± 9.4 at ≥15 years (P < .0001). The mean visual analog scale pain score decreased from 4.1 ± 0.7 preoperatively to 0.7 ± 0.3 at ≥15 years (P < .0001). The average SANE, SAS, and PROMIS-UE scores at ≥15 years were 87.8 ± 14.8, 8.8 ± 4.3, and 49.6 ± 10.2, respectively. Of 60 patients, 7 underwent revision surgery. Older age and female sex were associated with lower SAS scores at 15 years, whereas female sex was associated with lower PROMIS-UE scores. There were no factors predictive of ASES or SANE scores. CONCLUSION: At long-term follow-up (≥15 years), the patient-reported outcomes of all-arthroscopic rotator cuff repair show significant improvement from baseline preoperative function and remain durable over a period of 15 years. This information is useful in counseling patients regarding the long-term results of this procedure.
Subject(s)
Rotator Cuff Injuries , Rotator Cuff , Arthroscopy/methods , Female , Follow-Up Studies , Humans , Retrospective Studies , Rotator Cuff/surgery , Treatment OutcomeABSTRACT
BACKGROUND: The association between ball velocity and elbow varus torque has shown differences when evaluated within a single pitcher and within a cohort. The impact of increasing ball velocity on additional throwing-arm kinetics, in particular shoulder distraction forces, with intra- vs. inter-pitcher evaluations has not been evaluated, even though these kinetic measures have been implicated in injury risk. The purpose of this study was to compare intra- vs. inter-pitcher relationships between ball velocity and all major kinetics at the shoulder and elbow in professional pitchers. METHODS: A total of 323 professional baseball pitchers threw 8-12 fastball pitches while simultaneously being evaluated with 3-dimensional motion-capture technology (480 Hz). A linear regression analysis was performed to evaluate pitch velocity as a predictor of peak kinetic values at the shoulder and elbow among pitchers. A linear mixed model with random intercepts was then created to evaluate ball velocity as a predictor of peak kinetic values when comparing pitches within an individual pitcher. RESULTS: 91 pitchers were included in the analyses. Ball velocity among pitchers had weak correlations with shoulder distraction force (R2 = 0.228, P < .001) and elbow distraction force (R2 = 0.175, P < .001). Within an individual pitcher, strong correlations (R2 > 0.85) were observed for (1) shoulder internal rotation torque (P < .001), (2) shoulder horizontal adduction torque (P = .006), (3) shoulder superior force (P < .001), (4) shoulder anterior force (P < .001), (5) elbow varus torque (P < .001), (6) elbow medial force (P < .001), (7) elbow anterior force (P < .001), (8) elbow flexion torque (P < .001), (9) shoulder distractive force (P < .001), and (10) elbow distractive force (P < .001). CONCLUSION: Faster pitch velocity is a weak predictor of shoulder and elbow distraction forces experienced among professional pitchers. However, when controlling for an individual pitcher, peak kinetics at the shoulder and elbow can be strongly predicted by ball velocity. Therefore, the assumption that higher peak throwing-arm kinetic values are experienced by pitchers with faster ball velocity is likely an inappropriate assumption among pitchers but may be correct for each player who increases pitch velocity.
Subject(s)
Baseball , Elbow Joint , Biomechanical Phenomena , Elbow , Humans , Kinetics , TorqueABSTRACT
Background: Kinematic parameters predictive of pitch velocity have been evaluated in adolescent and collegiate baseball pitchers; however, they have not been established for high school or professional pitchers. Purpose: To create multiregression models using anthropometric and kinematics features most predictive for pitch velocity in high school and professional pitchers and compare them with prior multiregression models evaluating other playing levels. Study Design: Descriptive laboratory study. Methods: High school (n = 59) and professional (n = 337) baseball pitchers threw 8 to 12 fastballs while being evaluated with 3-dimensional motion capture (480 Hz). Using anthropometric and kinematic variables, multiregression models for pitch velocity were created for each group. A systematic review was conducted to determine previous studies that established kinematic models for ball velocity in youth, high school, and collegiate pitchers. Results: Leg length was predictive of pitch velocity for high school and professional pitchers (P < .001 for both). When compared with previously established models for pitch velocity, almost all groups were distinct from one another when assessing age (P maximum < .001), weight (P max = .0095), and pitch velocity (P max < .001). Stride length was a significant predictor for the youth/high school pitchers, as well as the current study's high school and professional pitchers (P < .001 for all). Maximal shoulder external rotation (collegiate: P = .001; professional: P < .001) and maximal elbow extension velocity (high school/collegiate: P = .024; collegiate: P < .001; professional: P = .006) were shared predictors for the collegiate and current study's professional group multiregression models. Trunk flexion at ball release was a commonly shared predictor in the youth/high school (P = .04), high school/collegiate (P = .003), collegiate (P < .001), and the current study's professional group (P < .001). Conclusion: Youth, high school, collegiate, and professional pitchers had unique, predictive kinematic and anthropometric features predictive of pitch velocity. Leg length, stride length, trunk flexion at ball release, and maximal shoulder external rotation were predictive features that were shared between playing levels. Clinical Relevance: Coaches, clinicians, scouts, and pitchers can consider both the unique and the shared predictive features at each playing level when attempting to maximize pitch velocity.
ABSTRACT
Background: Limited English language proficiency in patients undergoing total shoulder arthroplasty (TSA) may make treatment more challenging. Purpose: We sought to investigate the potential association between TSA patients' use of a language interpreter and 2 outcomes: hospital length of stay (LOS) and discharge disposition. Methods: We conducted a retrospective cohort study comparing LOS and discharge disposition after TSA for patients who required interpreter services and patients who did not at a single institution in an urban setting between 2016 and 2020. Consecutive patients requiring interpreter services who underwent TSA were matched 1:1 to patients who did not require an interpreter by age, body mass index (BMI), sex, and procedure. Multivariate regression models controlling for age, BMI, sex, smoking, opioid use, white or non-white race, procedure, and diagnosis were constructed to determine associations between interpreter use, LOS, and discharge disposition. Results: Forty-one patients were included in each cohort, exceeding the minimum number required per an a priori power analysis. Mean hospital LOS was longer in the interpreter cohort than in the non-interpreter cohort (2.8 ± 2.4 vs 1.8 ± 1.0 days, respectively). Multivariate linear regression demonstrated interpreter use was the strongest predictor of LOS, with the effect estimate indicating an additional 0.88-day LOS per patient. A greater proportion of patients from the interpreter cohort were discharged to an acute/subacute rehabilitation facility than patients from the non-interpreter cohort (n = 8 [19.5%] vs n = 2 [4.9%], respectively). Patients from the interpreter cohort were 454% more likely to be discharged to acute/subacute rehabilitation facilities. Conclusions: Our retrospective analysis of patients undergoing TSA suggests that the need for interpreter services may be associated with increased LOS and discharge to a facility. More rigorous study is needed to identify the factors that influence these outcomes and to avoid disparities in hospital stay and discharge.
ABSTRACT
BACKGROUND: It is unknown how different pitch count limits and rest day requirements affect cumulative pitch counts during a baseball season. PURPOSE: To determine (1) the variability of pitch count rules in high school baseball and (2) the theoretical effect of different pitch count limits and rest day combinations on game, weekly, and seasonal pitch totals in high school baseball pitchers. STUDY DESIGN: Cross-sectional study. METHODS: Pitch count rules for the 2019-2020 academic year for 48 sanctioned states were recorded from each state's athletic association website. Maximum pitch count limits were recorded along with the number of pitches allowed before requiring 0 to 5 rest days before the next pitching outing. Rules were also analyzed for several distinctions, including the athlete's level of competition, age, and grade. To determine the effect of pitch count rules and rest days, a theoretical 3-month season was calculated in the following scenarios: (1) variable maximum pitch count limits with a universal 3-day rest requirement, (2) universal 110 pitch count limit with variable rest day requirements (3, 4, or 5 days), and (3) actual pitch count limits and required rest days for every state assuming pitchers throw as many pitches as allowed. Analysis of variance and Student t tests were used to compare between-group and intragroup seasonal pitch totals based on variations in required rest days. RESULTS: The most common maximum pitch count limit for a varsity high school athlete was 110 pitches (range, 100-125 pitches) with 4 rest days (range, 0-5 days). We found that 23 states (48%) did not make distinctions for pitch count rules based on the athlete's level of competition, age, or grade. We noted a 25% increase in total seasonal pitch counts between the smallest and largest pitch count limit when assuming constant 3-day rest. We found a 53% difference in total seasonal pitch count when rest days varied between 3 and 5 days with a constant 110-pitch limit. Allowing 140 pitches in a 4-day span without a specific rest day requirement resulted in the highest seasonal pitch count (Nevada). There was a 49% difference in maximum seasonal pitch counts between the most and least restrictive states (P < .001). Submaximum pitch limits resulted in higher seasonal pitch counts than maximum pitch limits in 56% of states. CONCLUSION: Pitch count rules vary widely by state. Required rest days influenced total seasonal pitch counts more than maximum or submaximum pitch count limits.