A Systematic Review of Lower-Body Kinematic and Strength Factors Associated With Pitch Velocity in Adult Baseball Pitchers.

CONTEXT: Ball velocity for baseball pitchers is influenced by a multitude of factors along the kinetic chain. While a vast amount of data currently exist exploring lower-extremity kinematic and strength factors in baseball pitchers, no previous study has systematically reviewed the available literature. OBJECTIVE: The aim of this systematic review was to perform a comprehensive assessment of the available literature investigating the association between lower-extremity kinematic and strength parameters and pitch velocity in adult pitchers. EVIDENCE ACQUISITION: Cross-sectional studies that investigated the association between lower-body kinematic and strength factors and ball velocity in adult pitchers were selected. A methodological index for nonrandomized studies checklist was used to evaluate the quality of all included studies. EVIDENCE SYNTHESIS: Seventeen studies met the inclusion criteria comprising a total of 909 pitchers (65%, professional, 33% college, and 3% recreational). The most studied elements were hip strength and stride length. The mean methodological index for nonrandomized studies score was 11.75 of 16 (range = 10-14). Pitch velocity was found to be influenced by several lower-body kinematic and strength factors including the following: (1) hip range of motion and strength of muscles around the hip and pelvis, (2) alterations in stride length, (3) alterations in lead knee flexion/extension, and (4) several pelvic and trunk spatial relationships throughout the throwing phase. CONCLUSIONS: Based on this review, we conclude that hip strength is a well-established predictor of increased pitch velocity in adult pitchers. Further studies in adult pitchers are needed to elucidate the effect of stride length on pitch velocity given mixed results across multiple studies. This study can provide a basis for trainers and coaches to consider the importance of lower-extremity muscle strengthening as a means by which adult pitchers can improve pitching performance.

Kinematic Parameters Predictive of Pitch Velocity in Youth to Professional Baseball Pitchers: A Qualitative Systematic Review.

Background: Specific kinematic factors have been found to contribute to faster pitch speeds, with poor mechanics leading to injury. Purpose: To discuss the kinematic parameters that predict faster ball velocity among baseball pitchers. Study Design: Systematic review. Methods: Using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, the authors utilized the Cochrane Database of Systematic Reviews, PubMed (2008-2019), and OVID/MEDLINE (2008-2019) databases. Eligible articles included those that reported on kinematic factors predictive of ball velocity across youth, high school, collegiate, and professional levels of play. The quality of all included studies was evaluated by 2 reviewers using the Appraisal tool for Cross-Sectional Studies (AXIS). The lack of consistent study design or outcome variables precluded meta-analysis. Results: A total of 584 studies were identified from the initial search with 12 included in final analysis (930 pitchers in total; 429 [46.1%] youth, 164 [17.6%] high school, 153 [16.5%] collegiate and 184 [19.8%] professional) with mean ball velocity of 71.1 mph (114.4 km/h). The average AXIS score was 16 out of a possible 20. The shoulder played a significant role in the generation of velocity-induced torques. Hip and shoulder separation was associated with a 2.6 ± 0.5 mph (4.1 ± 0.8 km/h) increase in velocity, whereas increased shoulder movement of the nonthrowing arm was negatively correlated with initial ball velocity (r2 = 0.798). Furthermore, hip/shoulder separation, decreased movement of the nonthrowing shoulder, trunk power and timing of maximum trunk rotation, increased contralateral trunk tilt and increased sagittal-plane trunk tilt, and decreased knee flexion at ball release were all associated with higher fastball speeds. Conclusion: Multiple upper extremity and trunk kinematic parameters affect ball velocity, with significant contributions from the throwing shoulder and trunk, as well as nondominant arm. Understanding kinematic predictors of faster ball velocity can help guide training regimens.

Teaching in Orthopaedic Surgery: Effective Strategies for Educating the Modern Learner in a Modern Surgical Practice.

Prioritizing the education of orthopaedic surgery residents and fellows is essential for the future of the field. This review highlights strategies that educators may find useful in improving their teaching skills for the modern orthopaedic surgery learner. Educators may benefit from focusing on active, effortful, and repetitive engagement in lecture; setting clear expectations to help track progress in clinic; and breaking skills into smaller steps in context of a framework when teaching procedural skills. Providing objective assessment and growth-oriented feedback helps establish a close rapport between educator and trainee while encouraging personal development. Through a remediation process that examines deficiency in core areas and equitability of the learning environment, the trainee and the educator may engage in a fair discussion that prevents trainees from falling behind. Finally, in the era of COVID-19, e-learning and virtual simulations have become increasingly used as effective modalities for teaching clinical knowledge and procedures to trainees. The medical education landscape has been changing at a rapid pace, and by evaluating and adapting to the novel educational models of today, the modern orthopaedic surgeon ensures a learning environment that is equitable, effective, and inspiring for the orthopaedic surgeon of tomorrow.

Incidence of Carpal Tunnel Syndrome after Distal Radius Fracture.

Purpose: Carpal tunnel syndrome (CTS) can present following distal radius fracture (DRF) and may progress to require carpal tunnel release (CTR). The primary aim of this study was to determine the incidence of CTS within 6 months of a DRF and the rate of CTR in this population. Methods: We used the PearlDiver national insurance database to determine the incidence of CTS after DRF. Patients were identified by International Classification of Diseases-10 codes, and treatment modalities for DRF and CTS were determined by respective Current Procedural Terminology codes. Patients with less than 6 months of follow-up, bilateral DRF, or preexisting CTS were excluded. Patient demographic characteristics were recorded. The time from DRF diagnosis to CTS diagnosis and CTR was determined. A multivariable analysis was performed to determine the differences between patients who underwent a CTR compared with those who were treated conservatively. Results: We identified 23,733 patients (6,015 men; 17,718 women) who sustained a DRF. Of these patients, 79.1% were treated nonsurgically and 20.9% underwent surgical fixation. In total, 9.2% (N = 2,179) were diagnosed with CTS in their ipsilateral extremity within 6 months of sustaining the DRF. Of the patients whose DRF was treated nonsurgically, 6.3% (N = 1,198) developed CTS and 2.9% (N = 546) required CTR. Of those patients whose DRF was treated surgically, 19.8% (N = 981) developed CTS and 13.3% (N = 661) required CTR. Of those patients with symptoms severe enough to warrant CTR, 18.5% required a second surgical intervention for the CTR. Conclusions: Distal radius fractures severe enough to require surgical fixation are associated with a higher incidence of perioperative CTS. Accordingly, careful evaluation for and counseling on CTS during surgical fixation may decrease the chance of a second surgery. We have identified a cohort of patients with DRFs who may benefit from prophylactic CTR. Type of study/level of evidence: Diagnostic IV.

Abaloparatide Enhances Fusion and Bone Formation in a Rabbit Spinal Arthrodesis Model.

STUDY DESIGN: Prospective randomized placebo controlled animal trial. OBJECTIVE: Determine the effect of daily subcutaneous abaloparatide injection on the intervertebral fusion rate in rabbits undergoing posterolateral fusion. STUDY OF BACKGROUND DATA: Despite the wide utilization of spine fusion, pseudarthrosis remains prevalent, and results in increased morbidity. Abaloparatide is a novel analog of parathyroid hormone-related peptide (1-34) and has shown efficacy in a rat posterolateral spine fusion model to increase fusion rates. The effect of abaloparatide on the fusion rate in a larger animal model remains unknown. MATERIALS AND METHODS: A total of 24 skeletally mature New Zealand White male rabbits underwent bilateral posterolateral spine fusion. Following surgery, the rabbits were randomized to receive either saline as control or abaloparatide subcutaneous injection daily. Specimens underwent manual assessment of fusion, radiographic analysis with both x-ray and high-resolution peripheral quantitative computed tomography, and biomechanical assessment. RESULTS: Rabbits that received abaloparatide had a 100% (10/10) fusion rate compared with 45% (5/11) for controls ( P <0.02) as assessed by manual palpation. Radiographic analysis determined an overall mean fusion score of 4.17±1.03 in the abaloparatide group versus 3.39±1.21 for controls ( P <0.001). The abaloparatide group also had a greater volume of bone formed with a bone volume of 1209±543 mm 3 compared with 551±152 mm 3 ( P <0.001) for controls. The abaloparatide group had significantly greater trabecular bone volume fraction and trabecular thickness and lower specific bone surface and connectivity density in the adjacent levels when compared with controls. Abaloparatide treatment did not impact trabecular number or separation. There were no differences in biomechanical testing in flexion, extension, or lateral bending ( P >0.05) between groups. CONCLUSIONS: Abaloparatide significantly increased the fusion rate in a rabbit posterolateral fusion model as assessed by manual palpation. In addition, there were marked increases in the radiographic evaluation of fusion.

Serotonergic innervation of the auditory midbrain: dorsal raphe subregions differentially project to the auditory midbrain in male and female mice.

In the auditory inferior colliculus (IC), serotonin reflects features of context including the valence of social interactions, stressful events, and prior social experience. However, within the dorsal raphe nucleus (DRN; B6 + B7), the source of serotonergic projections to the IC has not been resolved at the level of DRN subregions. Additionally, few studies have investigated which DRN subregions are engaged during naturalistic, sensory-driven social behaviors. We employ traditional, retrograde tract-tracing approaches to comprehensively map the topographic extent of DRN-IC projection neurons in male and female mice. We combine this approach with immediate early gene (cFos) mapping in order to describe the functional properties of DRN subregions during contexts in which serotonin fluctuates within the IC. These approaches provide novel evidence that the dorsal (DRd) and lateral (DRl) B7 subregions are primarily responsible for serotonergic innervation of the IC; further, we show that this projection is larger in male than in female mice. Additionally, DRd and the ventral B7 (DRv) contained more transcriptionally active serotonergic neurons irrespective of behavioral context. Male mice had more active serotonergic neurons in DRd and DRv than females following sociosexual encounters. However, serotonergic activity was correlated with the expression of female but not male social behaviors. The topographic organization of the DRN-IC projection provides the anatomical framework to test a mechanism underlying context-dependent auditory processing. We further highlight the importance of including sex as a biological variable when describing the functional topography of DRN.