Dominant Elbow Research Articles

Are there kinematic and kinetic parameters correlated with racket velocity during the tennis serve? A preliminary comparison between a slow and a fast serve for performance improvement.

The tennis serve is a complex motion with numerous rotations which are important to manage for performance. The main aim of this study was to investigate kinematic parameters, including the evolution of the center of gravity, and kinetic parameters correlated with racket velocity over all phases of the tennis serve. The secondary objective was to find out which of the correlated parameters differed between a slow and a fast serve. The advantage of such an approach would be to propose biomechanical parameters that coaches and teachers could use to optimize performance or learn how to serve. Quantitative analysis was carried out on 5 flat serves performed by four ranked players using an optoelectronic system (82 markers located on whole body and racket) composed of 10 infrared cameras (150 Hz) and two force platforms (750 Hz). A descriptive statistical analysis highlighted 11 very large and almost perfect correlations with racket velocity: vertical ground reaction force of back foot in release backward, trunk axial rotation during loading phase, back and front knee flexions, dominant shoulder and hip mediolateral rotation during cocking phase, and center of gravity vertical velocity, dominant shoulder medial rotation velocity, dominant elbow flexion, trunk flexion/extension and axial rotation during acceleration phase. Differences were observed for some of the correlated parameters between slow and fast serve. Consequently, all these correlated kinematic and kinetics parameters constitute information that coaches, instructors and athletes can use to improve, optimize or teach the tennis serve.

Lateral Epicondylitis Treated with Platelet-Rich Plasma Injection and Corticosteroid Injection.

Lateral epicondylitis, or tennis elbow, affects 1%-3% of adults aged 35-50, causing pain and weakness in the dominant elbow due to chronic inflammation of the extensor tendon. While corticosteroid injections (CSI) are commonly used for treatment, they offer only short-term relief. Platelet-rich plasma (PRP) is a promising alternative with potential for long-term benefits. This study compares the efficacy of PRP and CSI in treating lateral epicondylitis. A randomized controlled trial was conducted at Chettinad Hospital and Research Institute from February 2020 to March 2021, involving patients with lateral epicondylitis unresponsive to non-invasive treatments. Patients were randomly assigned to receive either PRP or CSI, with pre- and post-treatment pain and function assessed using VAS, PSFS, and PRTEE scores. PRP showed better long-term pain reduction and functional improvement than CSI. At 6 months, PRP-treated patients had significantly lower VAS and PRTEE scores, indicating superior outcomes. Although CSI provided quicker initial relief, PRP demonstrated sustained benefits at 3 and 6 months. PRP's effectiveness in promoting tissue healing may explain its long-term success. PRP is more effective than CSI for long-term management of lateral epicondylitis, offering superior pain relief and functional improvement.

Body Part Pain Affects Subjective and Objective Handball Performance in Japanese Male National Athletes-Results of Short-Term Practical Monitoring of Athletes' Conditions.

This short-term survey examined the effect of body part pain on subjective and objective handball performance in Japanese male national handball athletes. Fourteen athletes participated in this study. Assessments of pain in 10 body parts and subjective performance (concentration and satisfaction with body movement) were performed using a visual analog scale from 0 to 10 over four consecutive training days. Monitoring of heart rate and body acceleration during training was also performed to quantify the objective performance. Path analysis and linear mixed modeling were employed to assess the relationship between body pain scores and subjective/objective handball performance. Over the four days of the study period, the body part in which most athletes reported pain was the dominant shoulder (6 of 14 athletes), followed by the dominant knee, the dominant elbow, the dominant ankle joint, and the non-dominant ankle joint (3 of 14 athletes). The path analysis revealed that pain in the dominant elbow negatively correlated with concentration (standardized path coefficient = -0.644, p = 0.00), which was associated with satisfaction with body movement (standardized path coefficient = 0.704, p = 0.00). No significant effect of body pain on objective performance (heart rate and body acceleration) was found among the athletes in this study. The results suggested that the elite athletes were practicing with pain. Even if pain does not physically affect athletes' objective performance, pain in the upper extremities, associated with the primary handball movement of throwing, may reduce the quality of practice by lowering athletes' subjective performance.

Elasticity assessment of flexor pronator muscles using shear wave elastography

BackgroundThe flexor pronator muscles (FPMs) have been thought as a dynamic stabilizer to protect the ulnar collateral ligament (UCL) from valgus stress during throwing motion. Thus, evaluation of the FPMs is important for preventing UCL injuries. Shear wave ultrasound elastography (SWE) is an imaging modality that quantifies tissue elasticity. The purpose of this study was to measure the tissue elasticities of healthy FPMs using SWE. MethodsWe investigated 22 healthy men (mean age, 29 ± 6 years). The elasticities of the FPMs, including the pronator teres (PT), flexor digitorum superficialis (FDS), and flexor carpi ulnaris (FCU), were measured using SWE for each arm under two conditions: at rest (unloaded) and under valgus stress (loaded). The values obtained under different loading conditions were compared between both elbows. ResultsThe mean SWE values of the PT, FDS, and FCU for the dominant elbows were 22.4 ± 3.6, 22.8 ± 2.9, and 22.3 ± 3.4 kPa, respectively. The corresponding mean SWE values for the non-dominant elbows were 24.2 ± 4.6, 23.1 ± 3.5, and 23.4 ± 3.5 kPa, respectively. The mean SWE values of the PT, FDS, and FCU at rest (unloaded) were 23.3 ± 4.2, 22.9 ± 3.2, and 22.9 ± 3.5 kPa, respectively. The corresponding mean SWE values under valgus stress (loaded) were 35.0 ± 6.2, 34.7 ± 5.3, 31.9 ± 4.8 kPa, respectively. ConclusionThis non-invasive evaluation of the stiffness of the FPMs may provide clinically relevant data for the prevention of UCL injuries.

Poster 207: Chronic Adaptations of the Ulnar Nerve in Professional Baseball Pitchers

Objectives: The presence of ulnar neuropathy in baseball pitchers is a poor prognostic factor of successful return to play and may adversely impact outcomes after ulnar collateral ligament reconstruction (UCLR). Screening programs to identify negative ulnar nerve adaptations in throwing athletes can help minimize injury risk, individualize treatment programs, and optimize rehabilitation. Ultrasound provides the advantage of viewing structural adaptations prior to the onset of symptoms, an important factor in identifying potential injuries in advance. However, it is currently unclear how the ulnar nerve adapts chronically in professional baseball pitchers. Therefore, the primary purpose of this study was to compare ulnar nerve ultrasound characteristics between the throwing (dominant) and non- throwing control (non-dominant) elbows in professional pitchers, with a secondary purpose of comparing ultrasound characteristics between subluxing and non-subluxing ulnar nerves. The authors hypothesized that ulnar nerve area and echogenicity (i.e. brightness) would be increased in the throwing elbow. Methods: All healthy professional baseball pitchers from a single organization underwent bilateral ultrasound examination at the beginning of the 2022 Minor League Baseball spring training. Ultrasound examination was done by a musculoskeletal radiologist (**) for imaging and subsequent quantification of the ulnar nerve properties, as well as to identify ulnar nerve subluxation. ImageJ software was utilized to measure ulnar nerve area, echogenicity (i.e. brightness), and circularity by one investigator (**) who was blinded to subluxation findings and arm dominance. Comparison of ulnar nerve ultrasound characteristics were performed between: dominant vs. non-dominant elbows, subluxing vs. non- subluxing dominant elbows, and between all (dominant and non-dominant) subluxing vs. non-subluxing elbows. Results: Overall, 74 male professional baseball pitchers (age: 22.5 ± 2.4 years; professional experience: 1.7 ± 1.5 years) were enrolled. There was a trend toward statistical significance for echogenicity bilaterally (dominant: 137 optical density vs. non-dominant: 128 optical density, p=0.053), while area (0.2 mm2 vs. 0.2 mm2, p=0.767) and circularity (0.67 vs. 0.69, p=0.165) did not differ bilaterally (Table 1). There were no demographic differences between pitchers with subluxing vs. non-subluxing dominant ulnar nerves, including similar years of professional experience and similar Beighton hypermobility scores between groups (Table 2). Echogenicity was significantly lower in subluxing dominant ulnar nerves compared to non-subluxing dominant ulnar nerves (128 optical density vs. 142 optical density, p=0.020). Echogenicity remained significantly lower in subluxing ulnar nerves after evaluating all subluxing vs. non-subluxing elbows (121 optical density vs. 138 optical density, p=0.001) (Table 3). Ulnar nerve area and circularity did not differ based on ulnar nerve subluxation. Conclusions: There was a trend towards the ulnar nerve of the throwing elbow having increased echogenicity relative to the non-throwing elbow, suggesting that echogenicity may play a role in the chronic adaptations of the ulnar nerve. Nerve echogenicity also differed based on ulnar nerve subluxation, however further research is necessary to determine why this difference exists and the potential direction of causality. [Table: see text][Table: see text][Table: see text]

The elbow is the load-bearing joint during arm swing

Background: Arm swing plays a role in gait by accommodating forward movement through trunk balance. This study evaluates the biomechanical characteristics of arm swing during gait.Methods: The study performed computational musculoskeletal modeling based on motion tracking in 15 participants without musculoskeletal or gait disorder. A three-dimensional (3D) motion tracking system using three Azure Kinect (Microsoft) modules was used to obtain information in the 3D location of shoulder and elbow joints. Computational modeling using AnyBody Modeling System was performed to calculate the joint moment and range of motion (ROM) during arm swing.Results: The mean ROM of the dominant elbow was 29.7°±10.2° and 14.2°±3.2° in flexion–extension and pronation–supination, respectively. The mean joint moment of the dominant elbow was 56.4±12.7 Nm, 25.6±5.2 Nm, and 19.8±4.6 Nm in flexion–extension, rotation, and abduction–adduction, respectively. Conclusions: The elbow bears the load created by gravity and muscle contracture in dynamic arm swing movement.

Effects of Unilateral Neuromuscular Electrical Stimulation with Illusionary Mirror Visual Feedback on the Contralateral Muscle: A Pilot Study.

We aim to examine the cross-education effects of unilateral muscle neuromuscular electrical stimulation (NMES) training combined with illusionary mirror visual feedback (MVF). Fifteen adults (NMES + MVF: 5; NMES: 5, Control: 5) completed this study. The experimental groups completed a 3-week NMES training on their dominant elbow flexor muscle. The NMES + MVF group had a mirror placed in the midsagittal plane between their upper arms, so a visual illusion was created in which their non-dominant arms appeared to be stimulated. Baseline and post-training measurements included both arms' isometric strength, voluntary activation level, and resting twitch. Cross-education effects were not observed from all dependent variables. For the unilateral muscle, both experimental groups showed greater strength increases when compared to the control (isometric strength % changes: NMES + MVF vs. NMES vs. Control = 6.31 ± 4.56% vs. 4.72 ± 8.97% vs. -4.04 ± 3.85%, p < 0.05). Throughout the training, even with the maximally tolerated NMES, the NMES + MVF group had greater perceived exertion and discomfort than the NMES. Additionally, the NMES-evoked force increased throughout the training for both groups. Our data does not support that NMES combined with or without MVF induces cross-education. However, the stimulated muscle becomes more responsive to the NMES and can become stronger following the training.

Anthropometric Study of Proximal Radius in Below-Average Height Thai Women and Its Correlation with Commercially Available Radial Head Prostheses.

Background: Most radial head prostheses were designed in Western countries based on the anatomical characteristics of Western populations. We hypothesised that these prostheses are too large for below-average height Thai women. The objective of this study is to evaluate the anthropometric parameters of the proximal radius in such a population and its correlation with commercially available prostheses. Methods: Dominant elbows of 124 Thai women whose height was <155 cm were studied. Using the standard anteroposterior and lateral radiographic images, the head diameter and thickness, the distance between the articular surface and radial tuberosity, the narrowest intra-medullary canal diameter and the narrowest outer diameter of the radial neck were measured. Correlations between body height and each radiographic parameter were assessed using the Pearson correlation coefficient (PCC). The specifications of the commercial metallic radial head implants were reviewed and used to evaluate the relevant radiographic parameters. Results: Mean of the minimum and maximum head diameter was 18.54 ± 1.11 mm and 19.13 ± 1.17 mm, respectively; the thickness was 7.43 ± 0.69 mm, the distance between the articular surface and tuberosity was 19.05 ± 1.45 mm, the intra-medullary canal diameter was 7.63 ± 1.2 mm and the outer diameter of the radial neck was 11.13 ± 1.26 mm. There is a poor correlation between the participant's height and each parameter (PCC ≤ 0.50). In 24.2% of the participants, the smallest size of prosthetic designs with a head diameter of 20 mm is larger than +2 mm in reference to minor diameter. The minimum prosthetic head thickness is greater than the average value of the participants in 12 out of 15 designs. One participant has an outer neck diameter smaller than the smallest stem diameter of three designs. Conclusions: Surgeons must be aware that commercially available radial head replacement implants may be too large for below-average height Thai women. Level of Evidence: Level IV (Prognostic).

Wide-Pulse High-Frequency Neuromuscular Electrical Stimulation Evokes Greater Relative Force in Women Than in Men: A Pilot Study.

This study aimed to examine the potential sex differences in wide-pulse high-frequency neuromuscular electrical stimulation (WPHF NMES)-evoked force. Twenty-two subjects (10 women) completed this study. Prior to the stimulation, the visual analogue scale (VAS) for discomfort and the rating of perceived exertion (RPE) were measured, followed by the isometric strength of the dominant elbow flexor muscles. The subjects then completed ten, 10-s on 10-s off WPHF NMES (pulse width: 1 ms, frequency: 100 Hz) at maximum tolerable intensities. The subjects’ RPE was recorded after each set, and the VAS was measured following the last stimulation. The stimulation induced significant increase in discomfort for both sexes, with women having greater discomfort than men (men: 22.4 ± 14.9 mm, women: 39.7 ± 12.7 mm). The stimulation amplitude was significantly greater in men than in women (men: 16.2 ± 6.3 mA, women: 12.0 ± 4.5 mA). For the evoked force, only the relative NMES-evoked force was found greater in women than in men (men: 8.96 ± 6.51%, women: 17.08 ± 12.61%). In conclusion, even at the maximum tolerable intensity, WPHF NMES evoked larger relative elbow flexion force in women than in men, with women experiencing greater discomfort.

Elbow joint salvage in pediatric traumatic amputation with targeted muscle reinnervation, external tissue expansion, and free muscle flap – A case report

The authors report targeted muscle reinnervation (TMR) in an 11-year-old male who sustained a trans-radial amputation of the right upper extremity in an ATV accident. A combination of targeted muscle reinnervation, external tissue expansion, and free muscle transfer allowed us to preserve elbow function, prevent neuroma formation, and allow for the future use of a myoelectric prosthetic. The use of TMR in pediatrics leverages the enhanced cortical plasticity of younger patients to improve outcomes and quality of life following traumatic injury, limiting the otherwise significant financial and psychosocial impact of amputation. This report offers the first account of TMR performed on a pediatric patient with no neuroma formation or phantom limb pain. • TMR redirects severed nerves to muscular targets. • This prevents neuroma and generates neural control for myoelectric prosthetic use. • TMR aided in the salvage of the dominant elbow joint of an 11-year-old male. • This is the first report of TMR in a pediatric upper extremity traumatic amputation.

Medial elbow joint space gapping associated with repetitive baseball pitching in preadolescent baseball players.

The baseball pitching motion creates valgus stress to the medial elbow, which contributes to increased medial elbow joint space gapping. The musculoskeletal systems of preadolescent baseball players are immature compared with those of adults, but it is unclear whether the repetitive pitching action causes an increase in medial elbow joint space gapping. This study aimed to examine differences in medial elbow joint space gapping based on the pitch count of preadolescent baseball players compared with those of adult players. The participants were 11 healthy preadolescent baseball players and 12 college students with baseball experience. They threw 60 maximal-effort pitches arranged into 4 sets of 15 pitches. The medial elbow joint space was measured ultrasonographically with the forearm weight before pitching and following every set of 15 pitches. Repeated-measures analysis of variance and the Bonferroni post hoc test were used to compare the medial elbow joint space among the 5 pitching sets (before pitching and after 15, 30, 45, and 60 pitches) and between the groups of preadolescent baseball players and college students. There was no significant change in the medial elbow joint space gapping of the dominant elbow based on age/pitch count (F=0.42, P=.796). There was a significant effect of pitch count (F=30.28, P<.001) and between-group effects (F=4.56, P=.045). The medial elbow joint space gapping increased significantly after 60 pitches in preadolescent baseball players (P=.023) and college students (P=.021). The medial elbow joint space gapping in preadolescent baseball players was significantly wider than that in college students (P=.007 before pitching, P=.027 at 15 pitches). Sixty repetitive pitches contributed to an increase in the medial elbow joint space gapping, regardless of age. The results of this study provide further evidence when considering pitching limitations.

Comparison of ground reaction forces and joint kinematics between three different tempos during push-up exercise

Abstract Study aim This study was aimed to analysis in detail how different tempos [2:0:2 (30 bpm), 1:0:1 (60 bpm), Explosive (EXP)] effect to ground reaction forces (vGRF) and joint kinematics of push-up exercise (PUP). Material and methods Twenty-four recreationally male athletes (age: 24.9 ± 3.6 years) participated in this study. Kinetic and kinematic data were obtained by load-cells and a motion analysis software. Data was analysed from a single repetition which is showed peak vGRF of dominant side during PUP. Joint velocities were calculated by taking the difference between the descent and ascent phases. Results There was significant difference between 2:0:2 (30 bpm) – EXP in terms of dominant side of shoulder (p ≤ 0.02) and between 1:0:1 (60 bpm) – EXP in the dominant elbow joint displacements (p ≤ 0.05). The velocity differences between the descent and ascent phases of shoulder and elbow joints were found statistically significant between tempos (p ≤ 0.05). In terms of range of motion (ROM) of right and left side, there was significant differences between tempos (p ≤ 0.001). No significant differences were found between all tempos in the ascent phase of right-left and left descent phase in terms of average vGRF (p &gt; 0.05) except right descent average vGRF (p ≤ 0.02). Conclusions In conclusion, right-left sides of ROM was used most effectively in 2:0:2 (30 bpm) and 1:0:1 (60 bpm) tempos. Less displacement was also observed in EXP and when tempo increased percentage of peak vGRF (at elbow flexion phase for right-left sides) to total repetition decreased. Highest ascent and descent phase velocity differences (for right-left sides) and highest peak vGRF (elbow flexion phase) observed in EXP. This study shows that increasing tempo will result in more unsteady joint kinematics and more vGRF, so if the goal is controlled and safe PUP, tempo should be slow.

Changes in elbow joint contact area in symptomatic valgus instability of the elbow in baseball players

The aim of this study was to evaluate the joint contact area of the dominant side and that of the non-dominant side without valgus instability in symptomatic pitchers. Ten symptomatic elbow medial ulnar collateral ligament (UCL) deficient baseball pitchers participated in this study. Computed tomography (CT) data from the dominant and non-dominant elbows were obtained with and without elbow valgus stress. The CT imaging data of each elbow joint were reconstructed using a 3D reconstruction software package, and the radiocapitellar and ulnohumeral joint contact areas were calculated. The center of the contact area and the translation from the position without stress to the position with valgus stress were also calculated. With elbow valgus stress, the contact area changed, and the center of the radiocapitellar joint contact area translated significantly more laterally in the dominant elbow than in the non-dominant elbow (p = 0.0361). In addition, the center of the ulnohumeral joint contact area translated significantly more posteriorly in the dominant elbow than in the non-dominant elbow (p = 0.0413). These changes in contact areas could be the reason for cartilage injury at the posterior trochlea in pitchers with UCL deficiency.

Development of a Mitochondrial Myopathy‐Composite Assessment Tool

'Mitochondrial Myopathy' (MM) refers to genetically-confirmed Primary Mitochondrial Disease (PMD) that predominantly impairs skeletal muscle function. Validated outcome measures encompassing core MM domains of muscle weakness, muscle fatigue, imbalance, impaired dexterity, and exercise intolerance do not exist. The goal of this study was to validate clinically-meaningful, quantitative outcome measures specific to MM. This was a single centre study. Objective measures evaluated included hand-held dynamometry, balance assessments, Nine Hole Peg Test (9HPT), Functional Dexterity Test (FDT), 30 second Sit to Stand (30s STS), and 6-minute walk test (6MWT). Results were assessed as z-scores, with < -2 standard deviations considered abnormal. Performance relative to the North Star Ambulatory Assessment (NSAA) of functional mobility was assessed by Pearson's correlation. In genetically-confirmed MM participants [n = 59, mean age 21.6 ± 13.9 (range 7 - 64.6 years), 44.1% male], with nuclear gene aetiologies, n = 18/59, or mitochondrial (mtDNA) aetiologies, n = 41/59, dynamometry measurements demonstrated both proximal [dominant elbow flexion (-2.6 ± 2.1, mean z-score ± standard deviation, SD), hip flexion (-2.5 ± 2.3), and knee flexion (-2.8 ± 1.3)] and distal muscle weakness [wrist extension (-3.4 ± 1.7), palmar pinch (-2.5 ± 2.8), and ankle dorsiflexion (-2.4 ± 2.5)]. Balance [Tandem Stance (TS) Eyes Open (-3.2 ± 8.8, n = 53) and TS Eyes Closed (-2.6 ± 2.7, n = 52)] and dexterity [FDT (-5.9 ± 6.0, n = 44) and 9HPT (-8.3 ± 11.2, n = 53)] assessments also revealed impairment. Exercise intolerance was confirmed by strength-based 30s STS test (-2.0 ± 0.8, n = 38) and mobility-based 6MWT mean z-score (-2.9 ± 1.3, n = 46) with significant decline in minute distances (slope -0.9, p = 0.03, n = 46). Muscle fatigue was quantified by dynamometry repetitions with strength decrement noted between first and sixth repetitions at dominant elbow flexors (-14.7 ± 2.2%, mean ± standard error, SEM, n = 21). All assessments were incorporated in the MM-Composite Assessment Tool (MM-COAST). MM-COAST composite score for MM participants was 1.3± 0.1(n = 53) with a higher score indicating greater MM disease severity, and correlated to NSAA (r = 0.64, p < 0.0001, n = 52) to indicate clinical meaning. Test-retest reliability of MM-COAST assessments in an MM subset (n = 14) revealed an intraclass correlation coefficient (ICC) of 0.81 (95% confidence interval: 0.59-0.92) indicating good reliability. We have developed and successfully validated a MM-specific Composite Assessment Tool to quantify the key domains of MM, shown to be abnormal in a Definite MM cohort. MM-COAST may hold particular utility as a meaningful outcome measure in future MM intervention trials.

Ultrasonographic prevalence of ulnar nerve displacement at the elbow in young baseball players.

Overhead-throwing athletes are at risk of elbow injury because of valgus stress, leading to unstable ulnar nerves and neuropathy. Studies regarding ulnar nerve damage/displacement have been performed primarily in adults. To determine the prevalence and related factors associated with ulnar nerve displacement at the elbow in young baseball players. Cross-sectional study. Youth baseball players ages 10-12 years were eligible to participate. Exclusion criteria were history of neuropathic pain, trauma, or prior surgery of the upper limb. Fifty-seven participants were eligible for inclusion in the study. Demographic data and ultrasonography findings of ulnar nerve dynamics at the cubital tunnel were analyzed in a total of 114 elbows. Elbows were grouped into nondislocation and displacement (subluxation or dislocation) groups according to ultrasound findings. Logistic generalized estimating equations were used to identify factors associated with ulnar nerve displacement. Thirty-six (31.6%) elbows demonstrated sonographic findings of ulnar nerve displacement, with 13 (11.4%) subluxations and 23 (20.2%) dislocations. Fourteen (24.6%) participants experienced nerve displacement in the dominant elbow only, whereas nerve displacement in both elbows occurred in 11 (19.3%) participants. Nerve displacement in the nondominant elbow only was not observed. Hand dominance and tenderness of the arcade of Struthers' were factors associated with ulnar nerve displacement (odds ratio, 2.81, and 9.73; 95% confidence interval, 1.34-5.91 and 2.45-38.68; p=.006 and .001, respectively). One-third of the young baseball players evaluated had ultrasonographic findings compatible with ulnar nerve displacement at the elbow. Hand dominance and tenderness of Struthers arcade were the only factors associated with ulnar nerve displacement. Ultrasound may help identify patients with ulnar nerve displacement and contribute to the understanding of its pathophysiology in young baseball players.

Prognostic Factors Affecting Long-Term Outcomes After Elbow Dislocation: A Longitudinal Cohort Study

PurposeTo describe patient-reported outcomes following simple elbow dislocation and to identify the baseline factors that predict outcomes.MethodsAdult patients treated with a closed reduction for a simple elbow dislocation with or without minor fracture (coronoid avulsion, radial head fracture, or epicondyle avulsion) from 2000 to 2018 completed outcome instruments including Disabilities of the Arm, Shoulder and Hand (QuickDASH) via Research Electronic Data Capture. Descriptive statistics were calculated. Univariate followed by multivariate Tobit regression models were used to determine factors associated with clinical outcomes on QuickDASH. Social deprivation was measured using the Area Deprivation Index. Patients with additional upper-extremity injuries or associated major fractures (Monteggia or terrible triad injuries, distal humerus fractures, etc) were excluded.ResultsAt a mean follow-up of 67.5 months, 95% (38/40) of patients reported satisfaction with treatment, and clinical outcomes were good (QuickDASH 9.0 ± 14.8). Univariate analysis showed that higher Area Deprivation Index, older age, female sex, high-energy mechanism of injury, and worker’s compensation (WC) or Medicare insurance status (vs commercial) was associated with significantly worse QuickDASH scores at follow-up. Early therapy, dominant elbow involvement, presence of minor fractures (minimally displaced radial head, coronoid tip, or epicondylar avulsion fractures), race, and treating service did not influence outcomes in univariate analyses. Multivariate analysis demonstrated a significant association between increased social deprivation, WC insurance, and Medicare insurance and worse QuickDASH scores while controlling for new upper-extremity injury, age, sex, and mechanism of injury.ConclusionsOutcomes and treatment satisfaction following simple elbow dislocation are generally good but are significantly worse for the patients with greater levels of social deprivation and WC or Medicare insurance. Although surgeons should be aware of the possibility that specific subsets of patients may benefit from early therapy, this factor did not appear to influence long-term outcomes in this small cohort.Type of study/level of evidencePrognostic III.

Return to Play After Platelet-Rich Plasma Injection for Elbow UCL Injury: Outcomes Based on Injury Severity.

Background:Ulnar collateral ligament (UCL) injuries of the elbow are uncommon in the general population but prevalent in the athletic community, particularly among baseball players. Platelet-rich plasma (PRP) injection therapy has become a popular nonoperative adjuvant treatment for such injuries to help reduce recovery time and avoid surgery.Purpose/Hypothesis:To analyze patient outcomes by injury severity and identify injury types that responded most favorably and unfavorably to PRP treatment. It was hypothesized that PRP therapy would prove to be most beneficial in the treatment of lower-grade, partial UCL tears and less effective in the treatment of more severe, complete UCL tears.Study Design:Cohort study; Level of evidence, 3.Methods:A cohort of 50 patients with UCL injuries in their dominant elbow, diagnosed by MRI (magnetic resonance imaging) arthrogram, underwent PRP therapy in conjunction with an established rehabilitation program. UCL injuries were classified by MRI as low-grade partial tear (Type I), high-grade partial tear (Type II), complete tear (Type III), or tear in more than 1 location (Type IV).Results:In total, 24 of 39 (61.5%) Type I and II tears, 3 of 3 (100%) Type III tears, and 1 of 8 (12.5%) patients with Type IV tears responded to UCL PRP injection therapy and were able to return to play without surgery. Ten patients required subsequent UCL PRP injections, of which 3 (30%) were able to return to sport without surgery.Conclusion:PRP treatment for Types I and II UCL tears shows great promise when combined with physical therapy and a rehabilitation program. Type III UCL tears demonstrated a high rate of success, although with low cohort numbers. Type IV UCL tears did not appear to respond well to PRP injection therapy and often required surgical intervention or cessation of sport. Therefore, PRP treatment does not appear to be appropriate for patients with complete Type IV UCL tears but may enhance recovery and improve outcomes in throwing athletes with Types I, II, and III UCL injuries.

Acellular Cartilage Repair Technique Based on Ultrapurified Alginate Gel Implantation for Advanced Capitellar Osteochondritis Dissecans.

Background:One of the most important limitations of osteochondral autograft transplant is the adverse effect on donor sites in the knee. Ultrapurified alginate (UPAL) gel is a novel biomaterial that enhances hyaline-like cartilage repair for articular defects. To avoid the need for knee cartilage autografting when treating osteochondritis dissecans (OCD) of the capitellum, we developed a surgical procedure involving a bone marrow stimulation technique (BMST) augmented by implantation of UPAL gel.Hypothesis:BMST augmented by UPAL gel implantation improves the cartilage repair capacity and provides satisfactory clinical outcomes in OCD of the capitellum.Study Design:Case series; Level of evidence, 4.Methods:A total of 5 athletes with advanced capitellar OCD in the dominant elbow underwent BMST augmented by implantation of UPAL gel. The osteochondral defects were filled with UPAL gel after BMST. At a mean follow-up of 97 weeks, all patients were evaluated clinically and radiographically.Results:At final follow-up, all 5 patients had returned to competitive-level sports, and 4 patients were free from elbow pain. The mean Timmerman-Andrews score significantly improved from 100 to 194 points. Radiographically, all patients exhibited graft incorporation and a normal contour of the subchondral cortex. Magnetic resonance imaging showed that the preoperative heterogeneity of the lesion had disappeared, and the signal intensity had returned to normal. Arthroscopic examinations consistently exhibited improvement in the International Cartilage Regeneration and Joint Preservation Society (ICRS) grade of lesions from 3 or 4 to 1 or 2 in 4 patients at 85 weeks postoperatively. Histologic analysis of biopsy specimens revealed an average total ICRS Visual Assessment Scale II histologic score of 1060.Conclusion:The acellular cartilage repair technique using UPAL gel for advanced capitellar OCD provided satisfactory clinical and radiographic results. The present results suggest that this novel technique is a useful, minimally invasive approach for treating cartilaginous lesions in athletes.

Sex moderates the effects of experimentally induced musculoskeletal pain on alcohol demand in healthy drinkers

BackgroundPain may serve as an antecedent for alcohol use, increasing risk for hazardous drinking and associated consequences. Delayed onset muscle soreness (DOMS) induction produces clinically relevant but time-limited musculoskeletal pain. This study was conducted to determine whether DOMS induction on the dominant elbow flexors influenced alcohol demand using the Alcohol Purchase Task (APT). We hypothesized DOMS would increase alcohol demand relative to a sham control. Based on existing studies of pain self-medication, we expected DOMS-related increases in alcohol demand would be greatest in men. MethodsParticipants (N = 53; 57 % women) were randomly assigned to a DOMS (eccentric exercise) or sham condition (concentric exercise). Participants completed the APT pre-exercise and 48 -hs post-exercise. Repeated measures GLM was used to characterize group by sex by time interactions on APT indices, including intensity, breakpoint, essential value (EV), Omax, and Pmax. ResultsThe DOMS procedure significantly increased pain ratings at the elbow flexors. Men had significantly higher demand intensity than women across groups and time points. Significant interactive effects were detected for breakpoint and EV. From pre- to post-test, breakpoint significantly increased in men in the DOMS group. However, breakpoint and EV significantly decreased in women in the DOMS group. ConclusionsIncreased alcohol demand in men in the DOMS group was consistent with epidemiological data suggesting men are at higher risk for self-medicating pain with alcohol than women. However, decreased demand in women was unexpected. Taken together, results indicate DOMS induction may be a useful means to characterize pain as an antecedent for alcohol use.

Ulnar collateral ligament dysfunction increases stress on the humeral capitellum: a finite element analysis.

BackgroundRepetitive mechanical stress on the elbow joint during throwing is a cause of ulnar collateral ligament dysfunction that may increase the compressive force on the humeral capitellum. This study aimed to examine the effects of ulnar collateral ligament material properties on the humeral capitellum under valgus stress using the finite element method.MethodsComputed tomography data of the dominant elbow of five healthy adults were used to create finite element models. The elbows were kept at 90° of flexion with the forearm in the neutral position, and the ulnar collateral ligament was reproduced using truss elements. The proximal humeral shaft was restrained, and valgus torque of 40 N·m was applied to the forearm. The ulnar collateral ligament condition was changed to simulate ulnar collateral ligament dysfunction. Ulnar collateral ligament stiffness values were changed to 72.3 N/mm, 63.3 N/mm, 54.2 N/mm, 45.2 N/mm, and 36.1 N/mm to simulate ulnar collateral ligament laxity. The ulnar collateral ligament toe region width was changed in increments of 0.5 mm from 0.0 to 2.5 mm to simulate ulnar collateral ligament loosening. We assessed the maximum equivalent stress and stress distribution on the humeral capitellum under these conditions.ResultsAs ulnar collateral ligament stiffness decreased, the maximum equivalent stress on the humeral capitellum gradually increased under elbow valgus stress (P < .001). Regarding the change in the ulnar collateral ligament toe region width, as the toe region elongated, the maximum equivalent stress of the humeral capitellum increased significantly under elbow valgus stress (P < .001). On the capitellum, the equivalent stress on the most lateral part was significantly higher than that on other parts (P < .01 for all).ConclusionUnder elbow valgus stress with elbow flexion of 90° and the forearm in the neutral position, ulnar collateral ligament dysfunction increased equivalent stress on the humeral capitellum during the finite element analysis. The highest equivalent stress was noted on the lateral part of the capitellum.