Dominant Elbow Research Articles

Predictors of Failure of Return to Play in Youth Baseball Players After Capitellar Osteochondritis Dissecans: Focus on Elbow Valgus Laxity and Radiocapitellar Congruity

Background: Osteochondritis dissecans of the humeral capitellum (capitellar OCD) is a common injury among youth baseball players, but there are only a few studies that report on return to play with nonoperative treatment. Purpose: To evaluate the medial elbow joint laxity under valgus stress and radiocapitellar congruity in patients with capitellar OCD and evaluate their relationship to predicting rehabilitation outcome. Study Design: Case-control study; Level of evidence, 3. Methods: Capitellar OCD was diagnosed in 81 patients included in our study. All patients were elementary school students who initially received rehabilitation treatment after injury. The rates of return to the same level of play or higher (RTSP) were calculated and correlated with the joint gap difference between the dominant and nondominant elbows using ultrasound and radiocapitellar congruity (proximal, lateral, and anterior radial translation length), which was assessed using plain radiographs of the dominant elbow. Results: The overall RTSP rates of patients with nonoperative treatment was 70.4% (57/81). The multivariate logistic regression analysis identified OCD classification (stage I, odds ratio [OR], 4.076; 95% CI, 1.171-14.190) and 1 continuous variable (proximal radial translation length on anteroposterior view, OR, 0.661; 95% CI, 0.479-0.911) as the significant predictive factors for outcome after nonoperative treatment. Conclusion: The early stage of capitellar OCD in youth baseball players can be successfully treated nonoperatively in the majority of cases. The presence of proximal radial translation can predict the outcome of nonoperative management of capitellar OCD.

An examination of acute cross-over effects following unilateral low intensity concentric and eccentric exercise

We compared the effects of low intensity concentric (CON) and eccentric (ECC) exercise on the force and neural responses of the dominant (exercised) elbow flexors (EFs), and studied if these conditions could induce cross-over effects to the contralateral (non-exercised) EFs. Fifteen subjects (8 males) completed all conditions (CON and ECC: 6 sets of low intensity exercise to failure; control: rest) in separate visits with a randomized order. Maximal isometric force and electromyography (EMG) of the dominant and contralateral EFs were assessed at pre, immediate-, 24-, and 48-h-post. Two-factor (condition and time) linear mixed-model analyses were performed to examine the force and EMG responses. Immediately post CON, contralateral EFs force was significantly (p = 0.026) higher (12.41%) than control, but no cross-over effects regarding the neural responses were observed. Immediately post ECC, dominant EFs force was significantly lower in ECC, compared to CON (p = 0.003) and control (p < 0.001). This force remained depressed at 24- and 48-h post ECC, when compared to CON (p < 0.001) and control (p < 0.001). Our data suggests that submaximal unilateral exercises are not likely to impair contralateral muscle strength performance. Instead, concentric exercises may acutely improve muscle strength for the contralateral limb. However, this effect is not explained by changes in muscle excitation.

Prospective study of pediatric medial humeral epicondyle fractures nonoperatively treated. Clinical, radiologic, and functional evaluation at long term.

The objective of the study is to evaluate the natural history of the medial epicondyle avulsion in children with nonoperative treatment (NOPT) on different magnitude of displacement and long-term follow-up. A prospective study of 34 patients with medial epicondyle avulsion with (NOPT) was performed. Clinical test (stability, strength, atrophy, tenderness, Tinel test, and range of motion), subjective scores [Visual Analog Scale (VAS), Likert scale, side-to-side valgus test], and objective four scores were performed. Age at the time of injury was 8.9 ± 2.81 years. Follow-up was 7 ± 2.81 years. Four of the patients had anterior displacement. Displacement varied between 3 and 26 mm (10.49 ± 6.16 mm). Subjective: VAS and ordinal three-point Likert scale were excellent. Objective results were also excellent Mayo Elbow Score: 98.67 ± 4.31 (85-100), Oxford Elbow Score: 59.35 ± 1.68 (51-100), Elbow Assessment Score System: 96.27 ± 9.77 (57-100), Disabilities of the Arm, Shoulder, and Hand (DASH) score 0.64 ± 1.001 (0-4.16). We did not find any differences in strength or forearm diameter. There was an extension deficit in seven cases with a significant association with the magnitude of displacement (P = 0.02) and with the presence of concomitant lesions or anterior displacement of the medial epicondyle >5 mm. All except one were stable clinically on valgus stress. There is a significant association between the objective outcomes (scores) and concomitant lesions but not with regards to the DASH score P = 0.102). There is no association between the magnitude of medial epicondyle displacement or the follow-up and the objective outcomes. Instability was associated with valgus stress activities. There is no association between the magnitude of displacement of the medial epicondyle or the follow-up and the objective outcomes. NOPT produces excellent subjective and objective outcomes that worsened when there were associated lesions, anterior medial epicondyle displacement, or in patients who performed activities with repeated valgus stress. Based on our study, NOPT is suitable except for Open Reduction Internal Fixation indications: absolute indications, high energy injury with associated lesions, medial humeral epicondyle fracture in the dominant elbow in patients subject to activities with chronic valgus stress, and anterior displacement.

Relationship Of Baseball Pitching Volume To Performance, Biometrics, And Reactive Hyperemia: A Pilot Study

We recently demonstrated body fat %, fast ball velocity, and RPE were significant predictors of valgus torque in NCAA baseball pitchers. Even though changes in hyperemic-induced limb volume are associated with acute, repetitive pitching performance, possibly indicating approaching dominant elbow soft-tissue risk, no investigation, to our knowledge, has examined relationships between performance, biometric, and throwing-limb volume in collegiate pitchers. PURPOSE: To quantify the relationship between pitching performance, subject biometrics, and hyperemic-induced changes in collegiate baseball pitchers during game-simulated pitching sessions of 40, 80, or 120 pitches. METHODS: Following informed consent, 5 male subjects (x̄ age = 18.8 ± 0.8 years; x̄ BMI = 27.6 ± 1.8; x̄ body fat % = 22.9 ± 6.2; x̄ throwing velocity = 80.4 ± 1.8 mph) were block-assigned to groups of 40, 80, or 120 pitches. Bouts consisted of 10 pitches (~20s between pitches) delivered from an artificial mound with 1-2 mins rest between bouts. HR and RPE were recorded immediately following each 10-pitch bout. A MOTUS sensor and compression sleeve measured elbow valgus torque. A Stalker Sport II Radar Gun measured fastball velocity. Pre-test and post-test upper- and lower-extremity limb girths were measured, signifying reactive hyperemia. Wilcoxon non-parametric testing determined pre- to post-test differences. Pearson correlation identified relationships between variables. Alpha was set at p ≤ 0.05. RESULTS: No group differences were found on any performance, biometric, demographic, or hemodynamic variable. HR (72.6 ± 8.3bpm vs. 97.6 ± 10.0bpm, p = 0.02) and dominant forearm limb girth (29.4 ± 1.5cm vs. 30.9 ± 1.5cm, p = 0.04) increased from pre-test to post-test for subjects combined. Significant correlations were found for: pitching volume & post-test HR (r = 0.90, p = 0.039); post-test dominant upper arm circumference & RPE (r = 0.89, p = 0.042), and; valgus torque % change & pitching volume (r = 0.91, p = 0.031). CONCLUSIONS: Forearm limb girth increased for subjects combined, and; given this metric’s indication of reactive hyperemia, future research focused on elucidating and quantifying the biological components of the tissue (compartments), as well as their contribution to performance- and/or injury-specific outcomes, is warranted.

Prevalence of lateral epicondylosis in veteran manual wheelchair users participating in adaptive sports

Objective: Determine the prevalence of lateral epicondylosis (LE) of the dominant elbow in manual wheelchair users based on ultrasound assessment and physical exam. Design: Prospective, cross-sectional. Setting: National Veteran Wheelchair Games 2018 and 2019 (event medical services). Participants: Manual wheelchair users who attended the National Veteran Wheelchair Games (n = 87). Interventions: Participants completed a questionnaire then underwent an ultrasound assessment and a physical exam of their dominant arm evaluating for common extensor tendinopathy (CET) or clinically LE. Main Outcome Measure: Prevalence of CET diagnosed by ultrasound criteria was compared with other diagnostic criteria with MaNemar test for paired binary data. Results: Forty-six percent (N = 40) of participants met diagnostic criteria for CET by ultrasound assessment and 17% (N = 15) of participants met criteria for LE based on physical exam. These values are dramatically higher than what has been reported in the able-bodied population where the prevalence is estimated to be <2%. Age and number of years of wheelchair use were significant predictors of ultrasound diagnosis of LE (P = 0.02, 95% confidence interval [CI] 1.01–1.11) and (P = 0.05, 95% CI 1.00–1.09), respectively. Association analysis based on odds ratio and CI found no association between ultrasound findings suggestive of LE with regular adaptive sport participation greater than 1.5 h per week. Conclusion: Compared to able-bodied population, there is an increased prevalence of both CET and LE in manual wheelchair users based on either ultrasound assessment or physical exam. CET is associated with increased age and increased years using a manual wheelchair. There is no association between the diagnosis of LE and participation in adaptive sport.

Safety of Transcranial Direct Current Electrical Stimulation in Dermatomyositis: A Case Report

Transcranial direct current stimulation (tDCS) has emerged as a nonpharmacological tool in physical rehabilitation. There have currently no studies that evaluated the safety and efficacy of tDCS in patients with dermatomyositis. Case-report: Three adult women with dermatomyositis were allocated randomly to intervention (i-tDCS, one patient) or not (sham-tDCS, two patients) of three consecutive days of tDCS and evaluated in four periods: before-tDCS (PRE), 15 minutes after-tDCS (0th POST), 15 days after-tDCS (15th POST), and 30 days after-tDCS (30th POST). The tDCS was safe throughout the protocol, without disease relapsing or adverse effects related to tDCS. Furthermore, the tDCS increased the muscle torque and total work of dominant and non-dominant elbow flexors in the patient with i-tDCS, when compared to two patients with sham-tDCS. Conclusions: The tDCS was safe and appeared to influence long-term strength in the limb of the patient with stable dermatomyo-sitis.

Progressive Elbow Magnetic Resonance Imaging Abnormalities in Little League Baseball Players Are Common: A 3-Year Longitudinal Evaluation

Background: Prior studies have revealed magnetic resonance imaging (MRI) evidence of elbow pathology in single-season evaluation of competitive youth baseball players. The natural history of these findings and risk factors for progression have not been reported. Purpose: To characterize the natural history of bilateral elbow MRI findings in a 3-year longitudinal study and to correlate abnormalities with prior MRI findings, throwing history, playing status, and physical examination. Study Design: Cohort study; Level of evidence, 2. Methods: A prospective study of Little League players aged 12 to 15 years was performed. All players had preseason and postseason bilateral elbow MRI performed 3 years before this study. Players underwent repeat bilateral elbow MRI, physical examination, and detailed assessment of throwing history, playing status, and arm pain. Imaging was read by a blinded musculoskeletal radiologist and compared with prior MR images to assess for progression or resolution of previously identified pathology. Results: All 26 players who participated in the previous single-season study returned for a 3-year assessment. At the completion of the study, 15 players (58%) had dominant arm MRI pathology. Eighty percent (12/15 players) of MRI findings were new or progressive lesions. Players with postseason MRI pathology at the beginning of the study were more likely to have MRI pathology at the 3-year follow-up than players with previously normal postseason MRI (P < .05), although 6 of the 14 players (43%) with previously normal MRI developed new pathology. Year-round play was a significant predictor of tenderness to elbow palpation (P = .027) and positive MRI findings at 3 years (P = .047). At the 3-year follow-up, 7 players (27%) reported having throwing elbow pain and 3 had required casting. Additionally, differences were noted in the dominant arm’s internal and external rotation in those that continued to play baseball (P < .05). Conclusion: Dominant elbow MRI abnormalities are common in competitive Little League Baseball players. Year-round play imparts significant risk for progression of MRI pathology and physical examination abnormalities.

Unilateral Elbow Flexion and Leg Press Training Induce Cross-Education But Not Global Training Gains in Children.

Whereas cross-education has been extensively investigated with adults, there are far fewer youth investigations. Two studies suggested that children had greater global responses to unilateral knee extensor fatigue and training, respectively, than adults. The objective of this study was to compare global training responses and cross-education effects after unilateral elbow flexion (EFlex) and leg press (LP) training. Forty-three prepubertal youths (aged 10-13y) were randomly allocated into dominant LP (n = 15), EFlex (n = 15) training groups, or a control (n = 13). Experimental groups trained 3 times per week for 8 weeks and were tested pretraining and posttraining for ipsilateral and contralateral 1-repetition maximum LP; knee extensor, knee flexors, elbow flexors; and handgrip maximum voluntary isometric contractions (MVIC), and countermovement jump. In comparison to no significant changes with the control group, dominant elbow flexors training demonstrated significant ( P < .001) improvements only with ipsilateral and contralateral upper body testing (EFlex MVIC [15.9-21.5%], EFlex 1-repetition maximum [22.9-50.8%], handgrip MVIC [5.5-13.8%]). Dominant LP training similarly exhibited only significant ( P < .001) improvements for ipsilateral and contralateral lower body testing (LP 1-repetition maximum [59.6-81.8%], knee extensor MVIC [12.4-18.3%], knee flexor MVIC [7.9-22.3%], and countermovement jump [11.1-18.1%]). The ipsilateral and contralateral training adaptations in youth were specific to upper or lower body training, respectively.

Isokinetic Strength of the Dominant and Non-dominant Elbow in Elite Male Volleyball Players

The purpose of this research is to compare the elbow isokinetic strength applied at different angular velocities on the dominant and non-dominant side in elite male volleyball players. Fifteen elite volleyball players participated in the research. Isokinetic elbow flexion and extension strength were separately obtained on concentric/concentric dominant and non-dominant side as 5 repetitions at 60˚.s-1 angular velocity, 10 repetitions at 180˚.s-1 and 15 repetitions at 300˚.s-1. In the research, the peak torque (PT), peak torque/body weight (PT/BW), flexion/extension ratio (B/T), angle of PT, work and power parameters were compared between the dominant and non-dominant elbows. No significant difference was found between the dominant and non-dominant side in the elbow isokinetic strength parameters of the subjects at three different velocities. A significant difference was found at three different velocities only in the angle of PT flexion (p &amp;lt; 0.05). It is thought that this difference may result from the muscle shortening that may occur on muscle length (longitudinal effect) as a result of the more concentric contraction of the muscle on the dominant side compared to the non-dominant muscle. Consequently, there is not any isokinetic strength difference between the dominant and non-dominant elbow in elite male volleyball players. Isokinetic elbow test can provide important information regarding the potential risk factors for elbow injuries. For this reason, it is recommended to include this test in the functional screening of volleyball players.

Ultrasonographic comparison of the lateral epicondyle in wheelchair-user (and able-bodied) tennis players: A pilot study

Objective: To evaluate whether manual wheelchair use and wheelchair tennis are associated with increased risk of lateral epicondylosis (LE). We hypothesized that the prevalence of LE would be highest in WC tennis players, followed by tennis players, WC users, and able-bodied subjects. Study design: Prospective cross-sectional pilot study. Setting: Milwaukee VAMC (clinic), National Veterans Wheelchair Games 2016 (medical event coverage). Participants: Wheelchair users, able-bodied controls, tennis players, non-tennis players. Interventions: Subjects meeting inclusion criteria underwent ultrasound examination of the dominant elbow evaluating for characteristics of LE (n = 83). Outcome measurements: Prevalence of LE between groups. Statistical analysis included odds ratios (OR), univariate and multivariate logistic regression. Results: There was no significant difference in diagnosis of LE between groups when comparing prevalence, unadjusted odds ratios, and predicted probabilities. When adjusted for age, able-bodied controls and tennis players had a similar increase in probability of LE with age; this effect was not seen for wheelchair users. Wheelchair users diagnosed with LE on US had spent significantly more time in a wheelchair (23 vs 13 years) than those with a negative diagnosis. Conclusions: Tennis playing in able bodied controls did not increase risk of LE. In wheelchair users, tennis playing does not appear to be associated with LE, though duration of wheelchair use appears to be a significant predictor of LE. Level of evidence: Level II.

Bone Mineral Density and Microstructure of the Elbow in Baseball Pitchers: An Analysis by Second-Generation HR-pQCT

Background: Baseball pitchers’ elbows are exposed to repeated overloading during the throwing motion, which causes bone structural changes such as bone sclerosis and osteophyte formation. They have been observed by clinical CT and MRI, while the bone microstructural change has not yet been studied in vivo. The aims of this study were to establish a method of imaging the elbow joint using second-generation high-resolution peripheral quantitative CT and to investigate the bone microstructural change in baseball pitchers’ dominant elbows. Methods: The subjects were 17 baseball pitchers. The elbow was fixed using a custom-made cast and scanned by second-generation high-resolution peripheral quantitative CT. The scan conditions were as follows: voxel size 60.7 μm, integration time 43 ms, scan length 30.6 mm, and total scan time 8 min. Volumetric bone mineral density (vBMD) and trabecular bone microstructure were analyzed in the 6.5-mm3 cubic regions set in the capitellum and trochlea, and the dominant and nondominant elbows were compared. Results: vBMD, bone volume fraction (BV/TV), and trabecular thickness (Tb.Th) at the capitellum were significantly higher in the dominant elbow than in the nondominant elbow. On the other hand, no parameters at the trochlea were significantly different. Conclusions: Higher vBMD accompanied by thicker trabecular bone was observed at the capitellum. These bone microstructural changes would reflect the valgus stress generated by the pitching motion in the elbow joint.

PROGRESSIVE ELBOW MRI ABNORMALITIES IN LITTLE LEAGUE BASEBALL PLAYERS ARE COMMON: A 3-YEAR LONGITUDINAL EVALUATION

Background Significant effort has been made by multiple organizations including Little League Baseball, USA Baseball, Major League Baseball, and the American Academy of Orthopaedic Surgeons to minimize the rate of shoulder and elbow injury among Little League Baseball players. Despite this effort, recent MRI studies have shown high rates of elbow pathology in this athletic population. The purpose of the current study was to track a cohort of Little League baseball players over three years with serial examinations and MRI to determine the natural history, progression, and risk factors of previously identified elbow pathology. Methods A prospective study of Little League players who were 12 to 15 years of age was performed. All players had preseason and postseason elbow MRI performed three years prior to the current study. Players underwent repeat bilateral elbow MRI, physical examination of bilateral shoulders and elbows, a detailed assessment of throwing history, and completed a questionnaire addressing playing history and current playing status, and any arm pain. The MRI scans were read by a blinded musculoskeletal radiologist and subsequently compared to players’ prior MRI to assess for progression or resolution of previously identified pathology. Identified MRI pathology was categorized as persistent/mild, progressive/severe, or improved/resolved (Figure 1). Results All 26 players who participated in the previous single season study returned for a 3-year longitudinal assessment, representing a 100% follow-up rate. Fifteen players (58%) had dominant arm MRI pathology. 80% of MRI findings (12/15 players) were determined to be new or progressive lesions. Players with post-season MRI pathology were significantly more likely to have MRI pathology at 3-years follow-up (p&lt;0.05). Six of the 14 players (43%) with previously normal MRI had new pathology. Year-round play was a significant predictor of tenderness to elbow palpation (p=0.027) and positive MRI findings at 3-years (p=0.047). Moderate/persistent and severe/progressive MRI findings were more often seen in players who continued to play baseball, play pitcher or catcher, and play year-round baseball (Figure 2). Dominant shoulder internal rotation was significantly less than non-dominant shoulder internal rotation amongst all players (60.3° compared with 71.2°, p=0.002). Dominant shoulder external rotation was significantly increased in players who continued to play baseball when compared with those no longer playing (109.1° versus 99.3°, p=0.012), in players playing pitcher or catcher when compared with non-pitchers/catchers (111.4° versus 100.3°, p=0.005), and in players who played year-round baseball when compared to those playing &lt; 8 months per year (109.0° versus 100.2°, p=0.026). Conclusion/Significance Dominant elbow MRI abnormalities are common in asymptomatic Little League baseball players. Three-year longitudinal evaluation suggests that these MRI findings commonly progress, especially amongst players who continue to play baseball. Year-round play appears to impart the most notable risk to young players, with results of the current study showing increased rates of physical exam abnormalities and progressive MRI pathology. Further guidelines addressing year-round play in Little League Baseball should be established.

Functional range of motion in the upper extremity and trunk joints: Nine functional everyday tasks with inertial sensors

BackgroundFunctional range of motion is defined as the required range of motions for individuals to maintain maximal independence, along with optimal conditions for activities of daily living. Intervention plans for rehabilitation are directed towards the acquisition of anatomical range of motion. However, this isn’t always possible based on person’s etiology, prognosis, or severity of disease. Research questionThe aim of this study is to determine functional range of motion during different unilateral, bilateral symmetrical and bimanual asymmetrical tasks of activities of daily living. MethodsParticipants completed nine basic activities of daily living (hand to head, hanging jacket, eating, wallet placement to back pocket, washing hands and face, removing belt, water pouring, brushing teeth) linked according to International Classification of Functioning, Disability and Health, while joint kinematics of the trunk and upper extremity were recorded with inertial measurement units. Peak values of mean joint angles were determined for each activities of daily living. MVN BIOMECH Awinda MTW2-3A7G6 sensors (Xsens Technologies B.V. Enschede, Netherlands) were used for 3D kinematic analysis of activities. ResultsForty-six healthy subjects (right-dominant) were included in this study. Range of motion requirements of all activities were defined 37.85° extension, 91.18° flexion, 1.25° adduction, 39.45° abduction, 63.6° internal rotation, 21.8° external rotation in the dominant shoulder, 124.17° flexion in the dominant elbow, 40.29° extension, 23.66° flexion, 18.31° supination, 12.56° pronation, 18.27 ulnar deviation and, 18.36° radial deviation in the dominant wrist. Maximum trunk range of motions were found to be 29.75° flexion in C7-T1, 10.74° flexion in T12-L1, and 24.16° flexion in L5-S1. SignificanceIt is thought that the results of this research will contribute to the determination of normative data needed for surgical interventions, technological rehabilitation devices and task-spesific rehabilitation programs which based patient's motor skill level.

Different Hemodynamic Responses of the Primary Motor Cortex Accompanying Eccentric and Concentric Movements: A Functional NIRS Study.

The literature contains limited evidence on how our brains control eccentric movement. A higher activation is expected in the contralateral motor cortex (M1) but consensus has not yet been reached. Therefore, the present study aimed to compare patterns of M1 activation between eccentric and concentric movements. Nine healthy participants performed in a randomized order three sets of five repetitions of eccentric or concentric movement with the dominant elbow flexors over a range of motion of 60° at two velocities (30°/s and 60°/s). The tests were carried out using a Biodex isokinetic dynamometer with the forearm supported in the horizontal plane. The peak torque values were not significantly different between concentric and eccentric movements (p = 0.42). Hemodynamic responses of the contralateral and ipsilateral M1 were measured with a near-infrared spectroscopy system (Oxymon MkIII, Artinis). A higher contralateral M1 activity was found during eccentric movements (p = 0.04, η² = 0.47) and at the velocity of 30°/s (p = 0.039, η² = 0.48). These preliminary findings indicate a specific control mechanism in the contralateral M1 to produce eccentric muscle actions at the angular velocities investigated, although the role of other brain areas in the motor control network cannot be excluded.

Normal imaging laterality on magnetic resonance imaging of the medial epicondyle of the elbow on the dominant side of adolescent male baseball players.

Multimodality elbow screening of adolescent baseball players shows apparent laterality in morphology and signal intensity of the medial epicondyle on dedicated magnetic resonance imaging. We aimed to elucidate actual imaging laterality in the medial epicondyle by comparing magnetic resonance images of the dominant and contradominant elbows and to clarify the clinical meaning and mechanism of this phenomenon. We used a 0.2-T dedicated magnetic resonance imaging scanner. Eighty adolescent baseball players were enrolled and divided into four age groups: 9-10years (13 patients); 11years (28 patients); 12years (24 patients) and 13-14years (15 patients). The long and short axes of the ossification center and distance of the epiphyseal plate and the cartilage of the lower pole of the medial epicondyle were measured. Signal intensity of the ossification center was visually evaluated. Owing to their age, ossification and cartilage size on the dominant side were significantly larger in all boys (P < 0.01). All age groups had larger ossification and cartilage in the dominant elbow (P < 0.01). Ossification showed an apparent lower signal intensity on the dominant side (P < 0.01). Larger ossification and cartilage size of the medial epicondyle in the dominant elbow suggested that the medial collateral ligament to the medial epicondyle induces excessive repetitive tensile stress, but without clinical symptoms. Functional or microanatomical damage of the medial epicondyle may induce a lower ossification signal in the dominant elbow, thereby decreasing fatty bone marrow and inducing sclerotic changes.

Mechanomyographic responses for the biceps brachii are associated with failure times during isometric force tasks.

In order to characterize the physiological adjustments within the neuromuscular system that contribute to task failure, this study examined the surface mechanomyographic (MMG) response during maximal and submaximal isometric force tasks of the elbow flexors sustained to failure. The time and frequency components of the MMG signal have shown to be influenced by motor unit activation patterns as well as tetanus. Therefore, it was hypothesized that the rate of change for the MMG response would associate with failure times and would be reduced to a similar degree between the two tasks. The isometric force tasks were performed by the dominant elbow flexors of twenty healthy males (age: 25 ± 4 years) and MMG was collected from the biceps brachii. Regression analyses were used to model the relationships between the rates of change for MMG versus failure times. There were high levels of interindividual variability in the response patterns, yet the models demonstrated significant negative associations between the rate of change for the MMG responses and failure times during both tasks (R 2 = 0.41–0.72, P < 0.05). Similarly, the mean MMG amplitude and frequency values were reduced to comparable levels at the failure point of the two tasks. The results of this study demonstrated that force failure is associated with the rate of diminution in the properties of the muscle force twitch.

Impact of rear wheel axle position on upper limb kinematics and electromyography during manual wheelchair use

Manual wheelchair propulsion is an important form of mobility for people with lower limb disabilities. Changes in the wheelchair configuration can affect, range of motion (ROM) of the upper limb joints, muscle actions and system stability. The purpose of this study is to investigate the impact of adjusting wheelchair configurations on upper body joints kinematics and muscle recruitment for able-bodied non experienced manual wheelchair users through applying a marker-based 3D motion analysis technique. Ten healthy male subjects were characterised for three wheelchair configurations, set by adjusting the horizontal axle position of both rear wheels by (3 cm) and (6 cm) posteriorly from the original position set by the manufacturer. Selected 3D kinematic and surface electromyography (sEMG) parameters of the upper body joints and shoulder muscles were measured in the Cardiff University Motion Analysis Laboratory. During the propulsion trials, trunk flexion/extension, lateral bending and axial rotation were evaluated within the average range of (7.50°±1.4°), (5.91°±1.23°) and (7.01°±3.91°), respectively. Dominant shoulder abduction/adduction, flexion/extension and internal/external rotation were evaluated within the average range of (24.63°±6.38°), (17.31°±4.27°) and (40.02°±12.35°), respectively. Dominant elbow pronation/supination and flexion/extension were evaluated within the range of (15.49°±7.70°) and (34.37°±8.38°), respectively. Dominant wrist radial/ulnar deviation and flexion/ extension were evaluated within the average range of (29.82°±8.97°) and (53.59°±9.65°), respectively. With normalising the muscle EMG to the percentage of MVC activity, posterior deltoid had the highest average EMG muscle activity (11.43 ± 5.33) during the propulsion trials and at the three wheel adjustments relative to the other dominant shoulder muscles. Other average muscles activities were evaluated as (6.99 ± 2.37) for upper trapezius, (6.89 ± 2.51) for triceps brachii, (5.39 ± 2.95) for anterior deltoid, (3.26 ± 1.00) for biceps brachii and (3.14 ± 1.26) for pectoralis major as the lowest average activity. The findings of this study indicate that changing rear wheel axle position posteriorly is correlated with increasing the kinematic ROMs of the trunk and dominant upper limb and the sEMG activities of the muscles predominantly involved with the recovery phase of propulsion which could be linked with higher risks of musculoskeletal disorders. This knowledge may help professionals when designing and prescribing wheelchairs that are more proper to users’ functional characteristics, accordingly profiting them improved quality of life.

Early Lateral Compartment Physeal Closure of the Elbow in Osteochondritis Dissecans of the Adolescent Baseball Players

Purpose The purpose of this study is to identify bilateral differences of physeal closure of the lateral compartment of the elbow in osteochondritis dissecans (OCD) and related factors with premature physeal closure. Methods Initial radiographs of the bilateral elbows in 40 baseball players with OCD (group I) were reviewed for the status of physeal closure of the lateral compartment; capitellum, radial head, lateral epicondyle. Forty baseball players with medial epicondylar apophysitis (group II) were enrolled as a control. Relative status of physeal closure of dominant elbow was defined as early, same, and delayed. Bilateral differences of the status of physeal closure were analyzed between groups, and according to the radiographic stages, extent of the lesions and demographic factors in group I. Results Significant early physeal closures of dominant elbows were identified in group I in capitellum (group I, 55%; group II, 3%), radial head (group I, 53%; group II, 3%), and lateral epicondyle (group I 37%; group II, 5%). In group I, advanced stage and extended lesion showed early lateral compartment physeal closure especially in capitellum and radial head, and players with longer career length and limitation of motion showed early closure. Conclusion Over the half of the adolescent baseball players with OCD demonstrated early radiocapitellar physeal closures of dominant elbow in initial presentation. Because premature physeal closure contributes to the development of arthritis without appropriate radiocapitellar remodeling, early detection of OCD is essential for prevention of arthritis and successful conservative management.

Frailty assessment in older adults using upper-extremity function: index development

BackgroundNumerous multidimensional assessment tools have been developed to measure frailty; however, the clinical feasibility of these tools is limited. We previously developed and validated an upper-extremity function (UEF) assessment method that incorporates wearable motion sensors. The purpose of the current study was to: 1) cross-sectionally validate the UEF method in a larger sample in comparison with the Fried index; 2) develop a UEF frailty index to predict frailty categories including non-frail, pre-frail, and frail based on UEF parameters and demographic information, using the Fried index as the gold standard; and 3) develop a UEF continuous score (points scores for each UEF parameter and a total frailty score) based on UEF parameters and demographic information, using the Fried index as the gold standard.MethodsWe performed a cross-sectional validation and index development study within the Banner Medical Center, Tucson, and Banner Sun Health Research Institute, Sun City, Arizona. Community-dwelling and outpatient older adults (≥60 years; n = 352; 132 non-frail, 175 pre-frail, and 45 frail based on Fried criteria) were recruited. For the UEF test, each participant performed a 20-s elbow flexion, within which they repetitively and rapidly flexed and extended their dominant elbow. Using elbow motion outcomes two UEF indexes were developed (categorical and score). The Fried index was measured as the gold standard.ResultsFor the categorical index, speed of elbow flexion, elbow range of motion, elbow moment, number of flexion, speed variability and reduction within 20 s, as well as body mass index (BMI) were included as the pre-frailty/frailty predictor parameters. Results from 10-fold cross-validation showed receiver operator characteristic area under the curve of 0.77 ± 0.07 and 0.80 ± 0.12 for predicting Fried pre-frailty and frailty, respectively. UEF score (0.1 to 1.0) was developed using similar UEF parameters.ConclusionsWe present an objective, sensor-based frailty assessment tool based on physical frailty features including slowness, weakness, exhaustion (muscle fatigue), and flexibility of upper-extremity movements. Within the current study, the method was validated cross-sectionally using the Fried index as the gold standard and the UEF categorical index and UEF frailty score were developed for research purposes and potentially for future clinical use.

Ultrasonographic Characteristics of the Common Extensor Tendon of the Elbow in Asymptomatic Individuals: Thickness, Color Doppler Activity, and Bony Spurs.

Background:Ultrasonography (US) of the common extensor tendon (CET) of the elbow is often part of the assessment of patients with lateral epicondylitis. This US assessment is currently based on general tendinopathy references and not well-defined US entities.Purpose:To describe CET thickness, color Doppler activity, and bony spurs on US in asymptomatic volunteers and to investigate the influence of sex, age, height, body mass index (BMI), weight, and elbow dominance on the measurements.Study Design:Cross-sectional study; Level of evidence, 3.Methods:Tendon thickness, color Doppler activity, and bony spurs of the CET were measured sonographically in 264 adults (50% women) aged 20 to 96 years. Two different tendon-thickness measuring techniques were applied, labeled the “plateau measure” and the “1-cm measure.” Color Doppler activity was based on a 0 to 4 rating scale (negative, grades 0 and 1; positive, grades 2-4). A bony spur was defined as a bony outgrowth (≥0.3 mm) arising at the insertional site of the CET.Results:With both tendon-thickness measuring techniques, the CET in the dominant elbow was thicker than that in the nondominant elbow, and male tendons were thicker than female tendons (all P ≤ .03). In regression analysis, tendon thickness correlated with weight, color Doppler activity, and arm dominance for both measuring techniques in multiple regression analysis. In addition, the plateau measure correlated with height and the presence of bony spurs. No correlations were observed regarding BMI, sex, or age. Positive color Doppler activity was found in 9% of examined elbows, with no difference between the sexes regarding dominant versus nondominant elbows (all P ≥.20). Bony spurs were found to increase with age, from 23% for people in their 20s to 74% in people older than 70 years. Bony spurs were more common in the dominant elbow (P ≤ .01). Women had a higher prevalence of bony spurs than men, but only in the dominant elbow (P = .03).Conclusion:This study presents the US characteristics and normal values of the CET. In 264 asymptomatic participants, the CET was found to be thicker in men and in the dominant elbow. No difference in tendon thickness could be demonstrated with regard to different age groups. Color Doppler activity was found to be positive in nearly 1 of 10 asymptomatic subjects. Bony spurs were a common finding; they increased in prevalence with every decade in age and were considered part of the aging process. Normal variations in CET morphologic characteristics should therefore be considered when implementing US in trials and clinical practice.