Elbow Motion Research Articles

Role of joint interactions in upper limb joint movements: a disability simulation study using wearable inertial sensors for 3D motion capture

BackgroundRestriction of movement at a joint due to disease or dysfunction can alter the range of motion (ROM) at other joints due to joint interactions. In this paper, we quantify the extent to which joint restrictions impact upper limb joint movements by conducting a disability simulation study that used wearable inertial sensors for three-dimensional (3D) motion capture.MethodsWe employed the Wearable Inertial Sensors for Exergames (WISE) system for assessing the ROM at the shoulder (flexion–extension, abduction–adduction, and internal–external rotation), elbow (flexion–extension), and forearm (pronation-supination). We recruited 20 healthy individuals to first perform instructed shoulder, elbow, and forearm movements without any external restrictions, and then perform the same movements with restriction braces placed to limit movement at the shoulder, elbow, and forearm, separately, to simulate disability. To quantify the extent to which a restriction at a non-instructed joint affected movement at an instructed joint, we computed average percentage reduction in ROM in the restricted versus unrestricted conditions. Moreover, we performed analysis of variance and post hoc Tukey tests (q statistic) to determine the statistical significance (p < 0.05 denoted using *) of the differences in ROM of an instructed joint in the unrestricted versus restricted conditions.ResultsRestricting movement at the shoulder led to a large reduction in the average ROM for elbow flexion–extension (21.93%, q = 9.34*) and restricting elbow movement significantly reduced the average ROM for shoulder flexion–extension (17.77%, q = 8.05*), shoulder abduction–adduction (19.80%, q = 7.60*), and forearm pronation-supination (14.04%, q = 4.96*). Finally, restricting the forearm significantly reduced the average ROM for shoulder internal–external rotation (16.71%, q = 3.81*) and elbow flexion–extension (10.01%, q = 4.27*).ConclusionsJoint interactions across non-instructed joints can reduce the ROM of instructed movements. Assessment of ROM in the real-world using 3D motion capture, for example using the WISE system, can aid in understanding movement limitations, informing interventions, and monitoring progress with rehabilitation.

Estimating elbow loading conditions through the motion behaviors of subchondral bone density during joint movements

Evaluating complicated stress across the elbow under joint motion remains difficult. Here, we aimed to evaluate the distribution of the subchondral bone density in the normal elbow bones and further characterize their spatial relationships during elbow motion to estimate the loading stress across the articular surface using three-dimensional computed tomography bone models. The normal elbow joint exhibited a consistent distribution pattern of subchondral bone density. High-density regions were distributed in the capitellum and posterior humeral trochlea, sagittal ridge of the ulnar trochlear notch and ulnar-volar side of the radial head. Motion analyses revealed that the high-density regions proximate with elbow flexion with forearm pronation in the radiocapitellar joint and in the fully extended position in the ulnohumeral joint. This reasonably reflects the stress acting on the joint surface under actual loading conditions. These findings suggest that daily activities involving lifting or carrying objects in these positions are stress-prone activities.

Quantitative biomechanical analysis in validating a video-based model to remotely assess physical frailty: a potential solution to telehealth and globalized remote-patient monitoring.

Assessing physical frailty (PF) is vital for early risk detection, tailored interventions, preventive care, and efficient healthcare planning. However, traditional PF assessments are often impractical, requiring clinic visits and significant resources. We introduce a video-based frailty meter (vFM) that utilizes machine learning (ML) to assess PF indicators from a 20s exercise, facilitating remote and efficient healthcare planning. This study validates the vFM against a sensor-based frailty meter (sFM) through elbow flexion and extension exercises recorded via webcam and video conferencing app. We developed the vFM using Google's MediaPipe ML model to track elbow motion during a 20s elbow flexion and extension exercise, recorded via a standard webcam. To validate vFM, 65 participants aged 20-85 performed the exercise under single-task and dual-task conditions, the latter including counting backward from a random two-digit number. We analyzed elbow angular velocity to extract frailty indicators-slowness, weakness, rigidity, exhaustion, and unsteadiness-and compared these with sFM results using intraclass correlation coefficient analysis and Bland-Altman plots. The vFM results demonstrated high precision (0.00-7.14%) and low bias (0.00-0.09%), showing excellent agreement with sFM outcomes (ICC(2,1): 0.973-0.999), unaffected by clothing color or environmental factors. The vFM offers a quick, accurate method for remote PF assessment, surpassing previous video-based frailty assessments in accuracy and environmental robustness, particularly in estimating elbow motion as a surrogate for the 'rigidity' phenotype. This innovation simplifies PF assessments for telehealth applications, promising advancements in preventive care and healthcare planning without the need for sensors or specialized infrastructure.

Next-gen strain sensors: Self-healing, ultra-sensitive, lightweight, and durable MWCNT-silicone rubber for advanced human motion tracking

Strain sensors that have flexible wearable forms can be applied in different aspects, such as in soft robotics, human-computer interaction, motion monitoring, and medical treatment process. The main challenge is creating lightweight, flexible sensors with high sensitivity. In this study, we developed flexible strain sensors using a simple sandwich manufacturing method. To achieve this, multi-walled carbon nanotubes (MWCNTs) were chosen for their excellent conductivity, while silicone rubber (SR) provided a flexible and durable substrate. Advanced SEM-EDX and FTIR analyses were conducted to assess the material structure. Furthermore, the electromechanical performance of the sensors was thoroughly evaluated, highlighting their potential in real-world applications. Electromechanical performance evaluation showed that the SR/0.7-MWCNT/SR sensor in the 0–90 % strain range had a sensitivity of 34.47, an increase of 53.35 %, and a linearity of 0.978, an increase of 10 % compared to the SR/0.5-MWCNT/SR sensor. In addition, the sensor has extremely fast response and recovery times of 65 ms and 60 ms, respectively. The sensor is also able to withstand up to 1.200 cycles of stretching, twisting, and bending. The sensor also exhibited good autonomous electromechanical self-healing properties against physical damage. The sensor developed in the present study are proven to be used to detect human movements such as finger bending, wrist, elbow, and knee movements.

Does Early Continuous Passive Motion Improves Effectiveness of Physical Therapy After Arthroscopic Release of Elbow Contracture: A Prospective Randomized Trial.

To investigate the effectiveness of early continuous passive motion combined with physical therapy compared to physical therapy alone as the rehabilitation protocol after the release of elbow contracture. In this randomized controlled trial, 61 patients were randomly assigned to two groups (31 in the early continuous passive motion with physical therapy group vs. 30 in the physical therapy group). The patients received rehabilitation with or without early continuous passive motion for 4 weeks and were followed up for 6 months. The outcome measures were the range of motion and Mayo Elbow Performance Score. The early continuous passive motion with physical therapy group demonstrated statistically significant improvements in range of motion and the Mayo Elbow Performance Score compared with the physical therapy group at 6 weeks, 3 months, and 6 months postoperatively. These differences were not observed in the stability subscale of the Mayo Elbow Performance Score at any of the assessed time points, nor in its pain subscale at 6 months. Compared with physical therapy alone, early continuous passive motion combined with physical therapy enabled a quicker recovery of functional elbow motion and early pain control within the 6-month follow-up after arthroscopic release of elbow contracture.

Bado type III Monteggia fractures have a high injury- and treatment-related complication rate: a single center study of 73 fractures.

Monteggia fractures can be problematic injuries. The aim of this population-based study is to evaluate the risk of complications according to the Bado types, clinical outcome, and incidence. 72 children (median age 6, range 2-11 years) with 73 Monteggia fractures treated during 2014-2022 were identified from the institutional fracture register. Timing of diagnosis, complications, and method of treatment were registered. Outcomes were assessed at mean 4 years (1-9) follow-up in 68 (94%) children. The census population (< 16 years old) in Helsinki metropolitan area during the study period was assessed. Bado types I (n = 43) and III (n = 27) comprised all but 3 of the fractures. Diagnosis was made on admission in 57, and with a 1-8-day delay in 16 children. 8 children had sustained an associated nerve injury. 35 children were treated operatively, 7 after failed closed treatment. 4 reoperations were performed, including 3 ulnar osteotomies. The risk of complications (odds ratio [OR] 4.9, 95% confidence interval [CI] 1.7-14) and closed treatment failures (OR 12.3, CI 1.3-118) was higher in Bado type III than in type I injuries. 60 children attended for clinical follow-up, all had congruent radio-humeral joints and full range of elbow and forearm motion. Mean PedsQL was 94 (72-100) and QuickDash 3 (0-13). 8 additional children reported normal elbow functions by phone. The calculated mean annual incidence of Monteggia injuries was 2.9/100,000 children. Monteggia fractures are rare (2.9/100,000 yearly). Bado type III injuries are associated with a high risk of complications.

Three-dimensional MRI analysis of elbow anatomy and kinematics in children with ulnar dimelia.

Ulnar dimelia often presents with restricted elbow movement. To develop a treatment strategy to improve elbow mobility, a detailed understanding of the skeletal deformity is needed. We created 3-D models of the cartilage and bone in the elbows of four children with ulnar dimelia by segmentation of MRI scans. We analysed the anatomy and performed a kinematic analysis. In all four children, the distal humerus was triangular in shape and consisted of a medial epicondyle, an enlarged lateral epicondyle and an anterior epicondyle. By comparing the 3-D images with conventional radiographs, we found that the projection of the enlarged lateral epicondyle created two longitudinal lines, which is a radiographic hallmark feature of the triangular-shaped distal humerus. In addition, during elbow flexion, the radial forearm bone slides along the lateral trochlea rather than rotates. This knowledge can aid surgeons to plan treatment for improving elbow mobility in ulnar dimelia.Level of evidence: IV.

Association of Clinical Findings With Complications in the Cubitus Varus Deformity After Supracondylar Fracture.

Cubitus varus deformity is primarily a cosmetic complaint that causes some early and late complications. However, no studies have reported the cubitus varus deformity regarding the frequency of complications, relationship to the degree of deformity, and period from the occurrence of the initial injury. Overall, 83 patients with cubitus varus deformity were examined. The differences in the humerus-elbow-wrist angle (∆HEW-A), tilting angle (∆TA), and internal rotation angle (∆IRA) between the affected and normal sides were measured to determine varus and extension and internal rotation deformity. The period from the occurrence of the initial injury to the evaluation date was also investigated. Multivariate logistic regression analysis was conducted to identify the explanatory variables (period, ∆HEW-A, ∆TA, and ∆IRA) independently associated with complication events. Receiver-operating characteristic curve analysis was also conducted to predict the risk of events. ∆HEW-A was independently associated with the risk of cosmetic complaint (odds ratio [OR], 1.171; 95% confidence interval [95% CI], 1.056 to 1.336) and instability (OR, 1.111; 95% CI, 1.028 to 1.200). ∆TA was independently associated with the risk of limited elbow motion (OR, 1.176; 95% CI, 1.077 to 1.285) and sports disability (OR, 0.892; 95% CI, 0.836 to 0.952). The period from the occurrence of the initial injury was independently associated with risk of pain (OR, 1.063; 95% CI, 1.019 to 1.108), ulnar nerve neuropathy (OR, 1.065; 95% CI, 1.011 to 1.125), and osteoarthritis (OR, 1.188; 95% CI, 1.098 to 1.286). The receiver-operating characteristic curve analysis revealed the optimal cutoffs of 20° and 27° for ∆HEW-A to predict cosmetic complaint and instability; of 25° for ∆TA to predict limited elbow motion; and of 8.8, 8.0, and 16.0 years for the period to predict pain, ulnar nerve neuropathy, and osteoarthritis, respectively. The treatment of cubitus varus deformity should be determined because a residual deformity >20° of varus and 25° of extension could develop risk of complications over time.

Fracture Patterns, Outcomes, and Complications of Terrible Triad Injury in Elderly Patients

AimsThe aim of this study was to describe the fracture patterns of terrible triad elbow injury (TTEI) and to evaluate complications, functional and radiographic outcomes in mid-term follow-up in patients older than 65 years. MethodsA retrospective study of 29 patients, mean follow-up of 48.7±4.6 months (range 65-78). Fractures were classified according to the Mason and Regan-Morrey classifications. All patients were evaluated by the Mayo Elbow Performance Scale (MEPS), Quick-Dash, EQVAS, EQ5D scores, and ROM measurement. ResultsThe mean age was 72.3 years and 79% were women. Mason Type III (72%) and Reagan-Morrey type II (69%) were the most frequent fracture type. All patients were managed with a lateral approach consisting of repair or replacement of the radial head and repair of the lateral ulnar collateral ligament (LUCL); of these patients, 19 underwent re-attachment of the coronoid process or anterior capsule. Mean functional scores were MEPS 90.3±7.5, Quick-DASH 18.4±4.6, EQ5D .89± 0.33, EQ-VAS 86.2 ± 21, and VAS 2.2± 1.5. Mean postoperative flexo-extension arc of elbow motion was 105º (range, 65º-145º). Two patients (7%) required revision surgery. We did not observe any joint instability in the elbow after surgery. ConclusionsPatients over 65 years old with a terrible triad elbow injury (TTEI) are at substantial risk of complex fracture patterns, particularly Mason type III radial head fractures and Regan-Morrey type II coronoid fractures. Complications such as joint stiffness and heterotopic ossification are infrequent, while associated capitellum fractures are not rare and should be considered in the assessment as they can impact elbow stability. Despite these challenges, surgical management generally achieves favorable functional outcomes with low complication and reoperation rates.

Enhancing Personalized Rehabilitation: Integrating Assist-as-Needed System With Real-Time Feedback

Abstract Conventional rehabilitation programs often lack precise real-time feedback, leading to varied training results at different centers. To address this, personalized rehabilitation strategies have been developed using robotic technologies and exoskeletons with assist-as-needed (AAN) controllers to improve recovery rates for individuals with stroke and neuromuscular disorders. This research introduces an automated therapy approach with a patient-specific AAN support strategy that provides immediate feedback, enhancing the rehabilitation process. The system uses minimal data to create effective personalized models and integrates sensors and algorithms for continuous monitoring, improving the efficacy of therapy. Initial trials with an exoskeleton that focused on elbow movements showed promising results in adjusting support in real-time and providing personalized interventions through torque-controlled motors. This system assesses impairment levels, visualizes motor energy needs, and helps design customized rehabilitation programs, significantly enhancing therapeutic results.

Flexible and Multifunctional Pressure/Gas Sensors with Polypyrrole-Coated TPU Hierarchical Array.

A promising strategy is proposed for fabricating flexible pressure/gas sensors, which have a microprotuberance and microwrinkle structure at micropillars on their sensing substrates. The sensing substrates were prepared by compression molding thermoplastic polyurethane (TPU; an industrial grade polymer) and subsequent pyrrole polymerization. Benefiting from the hierarchical structure on the sensing substrates, the flexible sensors exhibit high performances in detecting both pressure and ammonia (NH3). Mechanism for the functionalities of the hierarchical structure of the pressure sensors was analyzed. Such unique hierarchical structure endows the interlocked pressure sensor by assembling the substrates prepared at 60 min polymerization time with a relatively high sensitivity in a wider linearity range (1.15 kPa-1, 0-800 Pa), a lower detection limit of 6.2 Pa, and shorter response and recovery times (26/28 ms). The combination of stronger interfacial interaction between the TPU and polypyrrole layer, the mutual support of the interlocked micropillars, and the inherent high resilience of TPU endows the pressure sensor with lower hysteresis, good repeatability and stability, and higher durability (10,000 cycles). The interlocked pressure sensor can detect full-range human physiological activities from weak physiological signals (such as face muscle contraction, heartbeat, and breath) to body movements (such as head, elbow, and foot movement). The gas sensor assembled with the hierarchical sensing substrate prepared at 60 min polymerization time exhibits selective, stable, and faster sensing responses to NH3. The proposed facile and cost-effective preparation strategy can be an excellent candidate for fabricating high-performance and multifunctional sensors.

Using markerless motion capture and musculoskeletal models: An evaluation of joint kinematics.

This study presents a comprehensive comparison between a marker-based motion capture system (MMC) and a video-based motion capture system (VMC) in the context of kinematic analysis using musculoskeletal models. Focusing on joint angles, the study aimed to evaluate the accuracy of VMC as a viable alternative for biomechanical research. Eighteen healthy subjects performed isolated movements with 17 joint degrees of freedom, and their kinematic data were collected using both an MMC and a VMC setup. The kinematic data were entered into the AnyBody Modelling System, which enables the calculation of joint angles. The mean absolute error (MAE) was calculated to quantify the deviations between the two systems. The results showed good agreement between VMC and MMC at several joint angles. In particular, the shoulder, hip and knee joints showed small deviations in kinematics with MAE values of 4.8∘, 6.8∘ and 3.5∘, respectively. However, the study revealed problems in tracking hand and elbow movements, resulting in higher MAE values of 13.7∘ and 27.7∘. Deviations were also higher for head and thoracic movements. Overall, VMC showed promising results for lower body and shoulder kinematics. However, the tracking of the wrist and pelvis still needs to be refined. The research results provide a basis for further investigations that promote the fusion of VMC and musculoskeletal models.

The recovery and independence of elbow flexion and forearm supination after Oberlin II transfer in brachial plexus injuries: a long term follows up study.

The Oberlin II double fascicular nerve transfer has been evaluated extensively for objective outcomes for elbow flexion in brachial plexus injuries (BPI). However, there is limited information available on the recovery pattern of supination and patient-reported activity in the long-term. Our study aimed to assess the functional results with a minimum of five years of follow-up. We evaluated patients with a minimum of five years after the Oberlin II procedure for post-traumatic BPI. They were evaluated using MRC grading, range of active movements, QuickDASH score and activity to check elbow flexion and forearm supination independent of finger and wrist flexion. 18 out of 26 patients responded with a mean follow-up of 79.4months (range: 61-98). 16 (88.9%) (p < 0.000) patients recovered to achieve active elbow flexion and forearm supination of either MRC grade 3 power or more. The average range of active elbow flexion was 113.9° (range: 0-140°) and active supination was 67.8° (0-90°). Patients who achieved grade 3 flexion or higher were found to regain supination after a delay. The recovery continues even after two years of surgery. The mean QuickDASH score was 21.8 (range: 2.3-63.6). There's a significant inverse correlation between QuickDASH with both flexion and supination (p < .001 and < 0.05). 15 patients (83.3%) could demonstrate a dissociation of elbow and forearm movements from digital and wrist movements. Our study demonstrated reliable functional results with independent elbow flexion, forearm supination and acceptable patient-reported outcomes for Oberlin II procedure in BPI.

Self‐healing, adhesive, photothermal responsive, stretchable, and strain‐sensitive supramolecular nanocomposite hydrogels based on host–guest interactions

AbstractThe development of multifunctional supramolecular nanocomposite hydrogels remains challenging. Here, the dynamic host–guest interactions involving the host molecule CB[8] and guest units were utilized to prepare Fe3O4 hybrid supramolecular nanocomposite hydrogels. The results showed that the hydrogels obtained possessed a porous structure. The CB[8]‐modified Fe3O4 (Fe3O4@CB[8]) nanoparticles served as cross‐linkers in forming the network of hydrogels. By adjusting the Fe3O4@CB[8] content, the mechanical properties of the hydrogels could be controlled. The tensile stress was measured at 160 kPa with a fracture strain of 1380%, while the compression stress was 230 kPa at 70% compression strain. The self‐healing efficiency of the hydrogels at room temperature reached 95% after 24 h. The as‐obtained hydrogels show strain sensitivity and have the potential for applications in detecting elbow and finger movements. Our supramolecular nanocomposite hydrogels exhibit multiple functions, including self‐healing, injectability, photothermal responsiveness, and conductivity, making them suitable for integration into flexible electronics.Highlights Fe3O4@CB[8] nanoparticles serve as cross‐linkers for the nanocomposite hydrogels. CB[8] based host–guest interactions enable hydrogels to self‐heal. Fe3O4@CB[8] endow hydrogels with stretchability and photothermal responsiveness. Hydrogels exhibit injectability, NIR responsiveness, and conductive ability.

Is headless screw a valid alternative for the fixation of Chevron olecranon osteotomy? A biomechanical comparison of 4 fixation methods

BackgroundChevron osteotomy is a popular technique for repairing complex distal humerus intraarticular fractures. However, re-fixation presents challenges like hardware prominence and soft tissue damage. Headless cannulated screws are gaining popularity for fixation due to better bone purchase and less irritation. This study aims to compare different fixation strategies with headless screws for chevron osteotomy fixation. MethodsThis study utilized 32 polyurethane foam ulna specimens for biomechanical testing. The Chevron osteotomy was performed with an oscillating saw for all specimens. Four different techniques were used for re-fixation: modified tension band wire fixation, plate-screw fixation, cannulated screw fixation, and headless cannulated screw fixation. The constructs were mounted to the testing machine, simulating the elbow in 90 degrees of flexion. All specimens were tested under axial traction. Displacements at 350N and 500N and loads at the failure were recorded. ResultsAt the load of the implant failure, headless cannulated screw fixation revealed higher force values when compared to the other constructs, and modified tension band wire fixation showed lower force values compared to the other three groups (p < 0.001). The headless cannulated screw fixation group showed no significant differences in osteotomy displacements when tested to a 350N load. There were no significant differences in displacements at a 500N load between the four groups (p = 0.275). ConclusionThis study suggests that headless cannulated screw fixation is a viable and effective option for Chevron osteotomies. Headless cannulated screw fixation makes it a promising alternative to traditional fixation methods. This technique may be a more reliable fixation technique during daily activities and moderate elbow motions, indicating that it has the potential to succeed.

Highly Stretchable, Transparent, Self-Healing Ion-Conducting Elastomers for Long-Term Reliable Human Motion Detection.

The flexible electronic sensor is a critical component of wearable devices, generally requiring high stretchability, excellent transmittance, conductivity, self-healing capability, and strong adhesion. However, designing ion-conducting elastomers meeting all these requirements simultaneously remains a challenge. In this study, a novel approach is presented to fabricate highly stretchable, transparent, and self-healing ion-conducting elastomers, which are synthesized via photo-polymerization of two polymerizable deep eutectic solvents (PDESs) monomers, i.e., methacrylic acid (MAA)/choline chloride (ChCl) and itaconic acid (IA)/ChCl. The as-prepared ion-conducting elastomers possess outstanding properties, including high transparency, conductivity, and the capability to adhere to various substrates. The elastomers also demonstrate ultra-stretchability (up to 3900%) owing to a combination of covalent cross-linking and noncovalent cross-linking. In addition, the elastomers can recover up to 3250% strain and over 94.5% of their original conductivity after self-healing at room temperature for 5min, indicating remarkable mechanical and conductive self-healing abilities. When utilized as strain sensors to monitor real-time motion of human fingers, wrist, elbow, and knee joints, the elastomers exhibit stable and strong repetitive electrical signals, demonstrating excellent sensing performance for large-scale movements of the human body. It is anticipated that these ion-conducting elastomers will find promising applications in flexible and wearable electronics.

Assessment of joint position sense in active and passive modes with various elbow flexion angles and movement speeds using an isokinetic dynamometer

BackgroundJoint position sense is the ability to detect body segment position in space and is commonly used to represent proprioceptive performance. The isokinetic dynamometer is frequently used to evaluate elbow joint position sense during active and passive reproduction tasks with various testing protocols. However, few studies have reported the performance of joint position sense under different testing conditions. ObjectiveTo compare elbow joint position sense between active and passive reproduction tasks under different matching speeds and reference targets. DesignA cross-sectional study. MethodsTwenty participants without a history of upper-extremity surgery or neuromuscular diseases that affect the joint position sense of the elbow. Active and passive ipsilateral matching tasks were performed at four movement speeds (0.5°/s, 1°/s, 2°/s, and 4°/s) and three reference targets (elbow flexion at 0°–15°, 45°–60°, and 75°–90°), using an isokinetic dynamometer. The absolute and variable errors of each condition were calculated for comparison. ResultsIn active matching task with elbow flexion of 0°–15°, the absolute error at 0.5°/s was significantly larger than that at 2°/s and 4°/s, while the variable error at 1°/s was significantly larger than that at 2°/s. However, no differences were found at elbow flexion angles of 45°–60° and 75°–90°. Larger absolute errors were found at 4°/s with three testing angles in passive matching task. ConclusionsThis study compared the joint position sense errors under various testing conditions in the active and passive reproduction tasks. The movement speeds and target position effects should be considered during evaluation.

Trends in reported outcomes and patient reported outcome measures (PROMs) in humeral shaft fracture literature: a systematic review.

With a lack of standardization among outcome measures in fracture literature, cross-study comparisons remain limited. This systematic review aimed to identify trends in outcome measures reported by studies of the treatment of humeral shaft fractures. A systematic review was performed of studies reporting clinical outcomes of humeral shaft fractures indexed in PubMed. Extracted data included demographics, fracture characteristics, treatment modalities, outcomes, patient reported outcome measures (PROMs), and journal characteristics. Cochran-Armitage tests and linear regressions were used to identify data trends. Pearson chi-square and Kruskal-Wallis tests were used for comparisons between studies. This review included 197 studies with outcomes of 15,445 humeral shaft fractures. 126 studies reported PROMs and 37 different PROMs were used. The Constant Score was most commonly reported (34% of studies), followed by ASES Score (21%), MEPS (21%), and DASH Score (20%). There was a significant increase in PROM usage over time (p = 0.016) and in articles using three or more PROMs (p = 0.005). The number of PROMs were significantly greater in prospective cohort studies and RCTs (p = 0.012) compared to retrospective cohort studies and case series (p = 0.044 for both). Post-treatment shoulder motion was reported in 43% of studies and 34% reported elbow motion. 86% of studies reported complications as an outcome parameter. Time to union and nonunion rate were published in 69% and 88% of studies, respectively. This study identified increasing PROM usage over time and disparities in the reporting of outcomes in humeral shaft fracture literature requiring further validation and standardization of available outcome measures.

Force reserve predicts compensation in reaching movement with induced shoulder strength deficit.

Following events such as fatigue or stroke, individuals often move their trunks forward during reaching, leveraging a broader muscle group even when only arm movement would suffice. In previous work, we showed the existence of a "force reserve": a phenomenon where individuals, when challenged with a heavy weight, adjusted their motor coordination to preserve approximately 40% of their shoulder's force. Here, we investigated if such reserve can predict hip, shoulder, and elbow movements and torques resulting from an induced shoulder strength deficit. We engaged 20 healthy participants in a reaching task with incrementally heavier dumbbells, analyzing arm and trunk movements via motion capture and joint torques through inverse dynamics. We simulated these movements using an optimal control model of a 3-degree-of-freedom upper body, contrasting three cost functions: traditional sum of squared torques, a force reserve function incorporating a nonlinear penalty, and a normalized torque function. Our results demonstrate a clear increase in trunk movement correlated with heavier dumbbell weights, with participants employing compensatory movements to maintain a shoulder force reserve of approximately 40% of maximum torque. Simulations showed that while traditional and reserve functions accurately predicted trunk compensation, only the reserve function effectively predicted joint torques under heavier weights. These findings suggest that compensatory movements are strategically employed to minimize shoulder effort and distribute load across multiple joints in response to weakness. We discuss the implications of the force reserve cost function in the context of optimal control of human movements and its relevance for understanding compensatory movements poststroke.NEW & NOTEWORTHY Our study reveals key findings on compensatory movements during upper limb reaching tasks under shoulder strength deficits, as observed poststroke. Using heavy dumbbells with healthy volunteers, we demonstrate how forward trunk displacement conserves around 40% of shoulder strength reserve during reaching. We show that an optimal controller employing a cost function combining squared motor torque and a nonlinear penalty for excessive muscle activation outperforms traditional controllers in predicting torques and compensatory movements in these scenarios.

Minimum four-year clinical outcomes after on-table reconstruction technique for Dubberley type III in coronal shear fractures of the capitellum and trochlea: a report of 10 patients

PurposeComminuted coronal shear fractures of the distal humerus represent rare injuries and are difficult to treat, especially comminuted capitellum and trochlear fractures (Dubberley Type III). The on-table reconstruction technique of comminuted articular fractures may be an option, although it has not been reported in the coronal shear fracture of the distal humerus. The aim of the present case series is to determine the functional and radiological outcomes of on-table reconstructed Dubberley III fractures.MethodsA retrospective review was conducted of 10 patients with Dubberley type III fractures in coronal shear fractures of the capitellum and trochlea who underwent an ‘on-table’ reconstruction technique between January 2009 and October 2019. All patients were evaluated using the disabilities of the arm, shoulder, and hand (DASH) score, American Shoulder and Elbow Surgeons(ASES) score, Mayo Elbow Score Performance Index (MEPI) score and at least 4 years later.ResultsAll cases achieved union. At the final follow-up, the mean range of elbow motion was 11.5°of flexion contracture and 131.9° of further flexion. The mean DASH score was 21.2 (5.7) points (range 13.3–32.5). The mean ASES score was 88.6 ± 7.4 (range, 77 to 100). The mean MEPI score was 87 (10) points (range 70–100). In complication, partial osteonecrosis of capitellum is developed in one patient. One patient had heterotopic ossification without functional impairment.ConclusionThe on-table reconstruction technique can be a reliable option in the surgical treatment of complex distal humerus fractures. This technique allows anatomical reduction of comminuted capitellum and trochlea, with a low risk of avascular necrosis over 4 years of follow-up.Level of evidenceLevel IV, retrospective case series.