Finger Metacarpophalangeal Joint Research Articles

Hand Joint Hypermobility among Dental Students—A Cross-Sectional Study

(1) Background: Joint hypermobility refers to joint movement beyond normal range. Dentistry requires fine motor skills and manual dexterity; thus, the presence of hand joint hypermobility requires early assessment and intervention. The aim of this cross-sectional study was to assess the prevalence of hand joint hypermobility among first-year dental students and investigate correlations between the severity of their hypermobility and muscular strength. (2) Methods: First-year dental students were evaluated by an occupational therapy team composed of certified hand therapists. The extension of distal interphalangeal, proximal interphalangeal, and metacarpophalangeal finger joints was assessed with bilateral testing of digit hypermobility (with a cut-off of >20° for hypermobility) and classified as high, moderate, or low risk according to number/types of joints involved. Muscular strength was assessed by comparing grip strength, lateral pinch, and three-point pinch to norm values. Right- vs. left-handed individuals, and females vs. males were compared with an independent t-test; the relationships between the variables were investigated using the Pearson correlation. (3) Results: Out of 141 dental students (24.6 ± 3.0, 70% females, 87% right-handed), 15% and 16% were classified as having a high and moderate risk of hypermobility, respectively, with no sex difference. Right-handed students scored significantly higher in the right lateral pinch than left-handed students (18.2 ± 4.8 vs. 13.2 ± 4.1, p = 0.045). A higher severity of hypermobility was associated with bilateral lower grip and pinch strength (p < 0.05). (4) Conclusions: One third of the first-year dental students exhibited moderate to severe hand joint hypermobility. Moreover, those identified as having moderate to severe hand joint hypermobility showed a decreased grip strength.

E064 A rare hereditary haemochromatosis type three (3) related arthritis

Abstract Background/Aims Arthritis is a common manifestation in hereditary haemochromatosis (HHC). Haemochromatosis arthropathy frequently involves small joint of hands especially the metacarpo-phalangeal joints (MCPJs) and hence is one of the differentials when assessing for rheumatoid arthritis, psoriatic arthritis along with osteoarthritis but requires a high index of suspicion. We report a case of Haemochromatosis arthropathy where the arthropathy was due to type 3 hereditary haemochromatosis (HHC) which is a much rarer form and requires specialist genetic testing. Methods A 38-year-old lady was referred with abnormal iron profile and ten-month history of small joint arthralgia mainly affecting the index and middle finger in right hand with occasional swelling. She had a normal body mass index with minimal alcohol intake. Clinical examination showed low grade synovitis in index finger metacarpo-phalangeal joint (MCPJ). Blood investigations for Rheumatoid arthritis and connective tissue diseases were negative with normal CRP & ESR, Ferritin was slightly raised at 236 and transferrin saturation was 100% on two successive occasions, LFTs were normal. Xray of hands showed slight narrowing of 2nd MCPJ and US hands showed thickened synovium but no erosions or Doppler activity in 2nd MCPJ. Results Based on these, possible hereditary haemochromatosis (HHC) arthropathy was considered. By that time, she had been seen by the hepatology service where no evidence of iron deposition in other organs was found. Surprisingly her genetic testing for hereditary haemochromatosis (HHC) (Cys282Y/H63D in HFE gene) was negative resulting in most common HFE-related HHC excluded. Iron studies were repeated which were still raised, hence after discussion with hepatologist and biochemist the plan was made to investigate for rarer form of hereditary haemochromatosis (HHC), genetic tests showed that she had TFR2 variant mutation which would be consistent with type 3 hereditary haemochromatosis (HHC), which is inherited in autosomal recessive pattern. Venesections were started with ferritin levels improving to less than 50 with plans to monitor arthralgia to see if there is any improvement over time. Conclusion Metacarpo-phalangeal joints (MCPJs) involvement is common in various arthropathies. This case highlights the importance of considering other, much rarer forms of hereditary haemochromatosis (HHC) as treatment will help in preventing iron deposition in other organs like liver, heart, pancreas etc. These conditions are very rare and there is need to create awareness of genetic testing as hereditary haemochromatosis (HHC) arthropathy does present not uncommonly to rheumatology services and requires dedicated non-HFE molecular panel. Disclosure H. Umair: None. M. Kazmi: None.

Finger Metacarpophalangeal Joint Injuries in Athletes: Evaluation, Diagnosis, Treatment, and Return to Play.

Metacarpophalangeal (MCP) joint injuries of the fingers are frequent among athletes and can markedly affect an athlete's ability to perform at a high level. Despite this, MCP finger injuries in athletes are not frequently discussed, particularly in comparison with MCP joint injuries of the thumb, and remain unrecognized and undertreated injuries in this cohort. Accurate diagnosis and treatment of these injuries begins with an understanding of all the potential diagnoses. The purpose of this study was to review the pertinent anatomy and differential diagnoses for MCP joint injuries in athletes, including the evaluation and management to allow for safe and early return to play.

Proprioceptive response strength in the primary sensorimotor cortex is invariant to the range of finger movement

Proprioception is the sense of body position and movement that relies on afference from the proprioceptors in muscles and joints. Proprioceptive responses in the primary sensorimotor (SM1) cortex can be elicited by stimulating the proprioceptors using evoked (passive) limb movements. In magnetoencephalography (MEG), proprioceptive processing can be quantified by recording the movement evoked fields (MEFs) and movement-induced beta power modulations or by computing corticokinematic coherence (CKC) between the limb kinematics and cortical activity. We examined whether cortical proprioceptive processing quantified with MEF peak strength, relative beta suppression and rebound power and CKC strength is affected by the movement range of the finger.MEG activity was measured from 16 right-handed healthy volunteers while movements were applied to their right-index finger metacarpophalangeal joint with an actuator. Movements were either intermittent, every 3000 ± 250 ms, to estimate MEF or continuous, at 3 Hz, to estimate CKC. In both cases, 4 different ranges of motion of the stimuli were investigated: 15, 18, 22 and 26 mm for MEF and 6, 7, 9 and 13 mm for CKC. MEF amplitude, relative beta suppression and rebound as well as peak CKC strength at the movement frequency were compared between the movement ranges in the source space. Inter-individual variation was also compared between the MEF and CKC strengths.As expected, MEF and CKC responses peaked at the contralateral SM1 cortex. MEF peak, beta suppression and rebound and CKC strengths were similar across all movement ranges. Furthermore, CKC strength showed a lower degree of inter-individual variation compared with MEF strength.Our result of absent modulation by movement range in cortical responses to passive movements of the finger indicates that variability in movement range should not hinder comparability between different studies or participants. Furthermore, our data indicates that CKC is less prone to inter-individual variability than MEFs, and thus more advantageous in what pertains to statistical power.

Reliability, validity and clinical usability of a robotic assessment of finger proprioception in persons with multiple sclerosis.

Multiple sclerosis often leads to proprioceptive impairments of the hand. However, it is challenging to objectively assess such deficits using clinical methods, thereby also impeding accurate tracking of disease progression and hence the application of personalized rehabilitation approaches. We aimed to evaluate test-retest reliability, validity, and clinical usability of a novel robotic assessment of hand proprioceptive impairments in persons with multiple sclerosis (pwMS). The assessment was implemented in an existing one-degree of freedom end-effector robot (ETH MIKE) acting on the index finger metacarpophalangeal joint. It was performed by 45 pwMS and 59 neurologically intact controls. Additionally, clinical assessments of somatosensation, somatosensory evoked potentials and usability scores were collected in a subset of pwMS. The test-retest reliability of robotic task metrics in pwMS was good (ICC=0.69-0.87). The task could identify individuals with impaired proprioception, as indicated by the significant difference between pwMS and controls, as well as a high impairment classification agreement with a clinical measure of proprioception (85.00-86.67%). Proprioceptive impairments were not correlated with other modalities of somatosensation. The usability of the assessment system was satisfactory (System Usability Scale ≥73.10). The proposed assessment is a promising alternative to commonly used clinical methods and will likely contribute to a better understanding of proprioceptive impairments in pwMS.

A Novel Soft Glove Utilizing Honeycomb Pneumatic Actuators (HPAs) for Assisting Activities of Daily Living.

Fabric-based pneumatic actuators (FPAs) are extensively employed in the design of lightweight and compliant soft wearable assistive gloves. However, conventional FPAs typically exhibit limited output force, thereby restricting the applications of such gloves. This paper presents the development of a novel honeycomb pneumatic actuator (HPA) constructed using flexible thermoplastic polyurethane (TPU) coating through hot pressing or ultrasonic welding techniques. Compared to the previously utilized double-layer fabric-based pneumatic actuators (DLFPAs), the HPAs yields a remarkable 862% increase in end output force. It can produce a tip force of 13.57 N at a pressure of 150 kPa. The integration of HPAs onto a soft pneumatic glove enables the facilitation of various activities of daily living. A series of trials involving nine patients were conducted to assess the effectiveness of the soft glove. The experimental results indicate that when assisted by the glove, the patients' finger metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints achieved angles of 87.67 ± 19.27° and 64.2 ± 30.66°, respectively. Additionally, the average fingertip force reached 10.16 ± 4.24 N, the average grip force reached 26.04 ± 15.08 N, and the completion rate of daily functions for the patients increased from 39% to 76%. These outcomes demonstrate that the soft glove effectively aids in finger movements and significantly enhances the patients' daily functioning.

3D Hand Pose and Shape Estimation from Single RGB Image for Augmented Reality

In the realm of Human-Computer Interaction (HCI), the importance of hands cannot be overstated. Hands serve as a fundamental means of communication, expression, and interaction in the physical world. In recent years, Augmented Reality (AR) has emerged as a next-generation technology that seamlessly merges the digital and physical worlds, providing transformative experiences across various domains. In this context, accurate hand pose and shape estimation plays a crucial role in enabling natural and intuitive interactions within AR environments. Augmented Reality, with its ability to overlay digital information onto the real world, has the potential to revolutionize how we interact with technology. From gaming and education to healthcare and industrial training, AR has opened up new possibilities for enhancing user experiences. This study proposes an innovative approach for hand pose and shape estimation in AR applications. The methodology commences with the utilization of a pre-trained Single Shot Multi-Box (SSD) model for hand detection and cropping. The cropped hand image is then transformed into the HSV color model, followed by applying histogram equalization on the value band. To precisely isolate the hand, specific bounds are set for each band of the HSV color space, generating a mask. To refine the mask and diminish noise, contouring techniques are applied to the mask, and gap-filling methods are employed. The resultant refined mask is then combined with the original cropped image through logical AND operations to accurately delineate the hand boundaries. This meticulous approach ensures robust hand detection even in complex scenes. To extract pertinent features, the detected hand undergoes two concurrent processes. Firstly, the Scale-Invariant Feature Transform (SIFT) algorithm identifies distinctive keypoints on the hand's outer surface. Simultaneously, a pre-trained lightweight Convolutional Neural Network (CNN), namely MobileNet, is employed to extract 3D hand landmarks, the hand's center (middle finger metacarpophalangeal joint), and handedness information. These extracted features, encompassing hand keypoints, landmarks, center, and handedness, are aggregated and compiled into a CSV file for further analysis. A Gated Recurrent Unit (GRU) is then employed to process the features, capturing intricate dependencies between them. The GRU model successfully predicts the 3D hand pose, achieving high accuracy even in dynamic scenarios. The evaluation results for the proposed model are very promising that the Mean Per Joint Position Error in 3D (MPJPE) is 0.0596 between the predicted pose and the ground truth hand landmarks, while the Percentage of Correct Keypoints (PCK) is 95%. Upon predicting the hand pose, a mesh representation is employed to reconstruct the 3D shape of the hand. This mesh provides a tangible representation of the hand's structure and orientation, enhancing the realism and usability of the AR application. By integrating sophisticated detection, feature extraction, and predictive modeling techniques, this method contributes to creating more immersive and intuitive AR experiences, thereby fostering the seamless fusion of the digital and physical worlds.

Self-Calibrating Magnetometer-Free Inertial Motion Tracking of 2-DoF Joints.

Human motion analysis using inertial measurement units (IMUs) has recently been shown to provide accuracy similar to the gold standard, optical motion capture, but at lower costs and while being less restrictive and time-consuming. However, IMU-based motion analysis requires precise knowledge of the orientations in which the sensors are attached to the body segments. This knowledge is commonly obtained via time-consuming and error-prone anatomical calibration based on precisely defined poses or motions. In the present work, we propose a self-calibrating approach for magnetometer-free joint angle tracking that is suitable for joints with two degrees of freedom (DoF), such as the elbow, ankle, and metacarpophalangeal finger joints. The proposed methods exploit kinematic constraints in the angular rates and the relative orientations to simultaneously identify the joint axes and the heading offset. The experimental evaluation shows that the proposed methods are able to estimate plausible and consistent joint axes from just ten seconds of arbitrary elbow joint motion. Comparison with optical motion capture shows that the proposed methods yield joint angles with similar accuracy as a conventional IMU-based method while being much less restrictive. Therefore, the proposed methods improve the practical usability of IMU-based motion tracking in many clinical and biomedical applications.

EARLY ACTIVE MOBILIZATION AFTER RECONSTRUCTION OF RUPTURED FINGER EXTENSOR TENDONS AT THE WRIST JOINT

Background: Subcutaneous spontaneous ruptures of the finger extensor tendons at the wrist frequently occur. This study aims to evaluate the outcomes of patients with extensor tendon ruptures treated by our operative methods and postoperative early active mobilization. Methods: A total of 38 patients with 68 extensor tendon ruptures were included in this study. In the reconstruction of extensor tendon ruptures, tendon transfers (extensor indicis proprius (EIP) tendon transfer and/or interlacing end-to-side suture) and/or free tendon bridge graftings were performed. Immediately after operation in all patients, early active mobilization began by wearing a specially designed bandage or splint. Results: There was no reoccurrence of re-rupture of a tendon post surgery. A patient satisfaction survey revealed that 29 patients rated their results as “excellent” and 9 were “good.” Postoperatively, the active range of motion of the finger metacarpophalangeal (MP) joint averaged +3∘(range:- 14[Formula: see text]+20∘) in extension and 69∘(range: 60–80∘) in flexion. Conclusions: We treated finger extensor tendon ruptures by tendon transfer (EIP tendon transfer to the ruptured extensor tendon and/or interlacing end-to-side suture) and/or bridge tendon grafting. We employed early active mobilization with patients wearing a specially designed bandage or splint immediately after reconstructing surgery. There was no case with re-rupture postoperatively. Our operative techniques and postoperative physiotherapy as early active mobilization in this study led to excellent results after finger extensor tendon ruptures.

Reliable and Valid Robotic Assessments of Hand Active and Passive Position Sense in Children With Unilateral Cerebral Palsy.

Impaired hand proprioception can lead to difficulties in performing fine motor tasks, thereby affecting activities of daily living. The majority of children with unilateral cerebral palsy (uCP) experience proprioceptive deficits, but accurately quantifying these deficits is challenging due to the lack of sensitive measurement methods. Robot-assisted assessments provide a promising alternative, however, there is a need for solutions that specifically target children and their needs. We propose two novel robotics-based assessments to sensitively evaluate active and passive position sense of the index finger metacarpophalangeal joint in children. We then investigate test-retest reliability and discriminant validity of these assessments in uCP and typically developing children (TDC), and further use the robotic platform to gain first insights into fundamentals of hand proprioception. Both robotic assessments were performed in two sessions with 1-h break in between. In the passive position sense assessment, participant's finger is passively moved by the robot to a randomly selected position, and she/he needs to indicate the perceived finger position on a tablet screen located directly above the hand, so that the vision of the hand is blocked. Active position sense is assessed by asking participants to accurately move their finger to a target position shown on the tablet screen, without visual feedback of the finger position. Ten children with uCP and 10 age-matched TDC were recruited in this study. Test-retest reliability in both populations was good (intraclass correlation coefficients (ICC) >0.79). Proprioceptive error was larger for children with uCP than TDC (passive: 11.49° ± 5.57° vs. 7.46° ± 4.43°, p = 0.046; active: 10.17° ± 5.62° vs. 5.34° ± 2.03°, p < 0.001), indicating discriminant validity. The active position sense was more accurate than passive, and the scores were not correlated, underlining the need for targeted assessments to comprehensively evaluate proprioception. There was a significant effect of age on passive position sense in TDC but not uCP, possibly linked to disturbed development of proprioceptive acuity in uCP. Overall, the proposed robot-assisted assessments are reliable, valid and a promising alternative to commonly used clinical methods, which could help gain a better understanding of proprioceptive impairments in uCP, facilitating the design of novel therapies.

Outcomes of a Trans-Web Approach to Fractures around the Finger Metacarpophalangeal Joint.

Background: A fracture around the finger metacarpophalangeal joint (MCPJ) can be difficult to access. We developed a trans-web approach that could lead surgeons directly to this site. An incision across the web is believed to result in a web contracture. The aim of this study is to present the outcomes of the trans-web approach. Methods: This is a retrospective study of all patients in whom a trans-web approach was used to fix fractures around the MCPJ in the period from October 2008 and September 2020. The outcomes of the trans-web approach were evaluated by appearance of the scar, presence of pain in relation to the scar, grading web creep, range of motion at the MCPJ and degree of abduction and adduction of the finger. Any complications of surgery were also recorded. Results: This study included 10 patients with 11 fractures around the MCPJ (6 avulsion fractures and 5 extra-articular fractures). The mean follow-up was 5 months. Skin contractures did not occur in any avulsion fracture case where original or extended trans-web skin incisions were used. However, they occurred in 2 extra-articular cases treated via a trans-web plus a mid-lateral approach. The mean range of motion of the MCP joint in all the patients was 80° (range, 70°-95°). There was a 10° loss of abduction in one patient and temporary sensory disturbance in another patient. Both these patients had been treated with extended incisions. Conclusions: The trans-web incision is a useful approach for the open reduction of fractures around the finger MCPJ, especially in avulsion fractures of the lateral volar base of the proximal phalanx with minimal risk of scar contracture. The risk of scar contracture is higher when the trans-web incision is combined with a mid-lateral incision for extra-articular fractures. Levels of Evidence: Level IV (Therapeutic).

P 61 Robotic assessments of upper limb sensorimotor impairments in neurological disorders

Background: Upper limb sensorimotor impairments are common in neurological disorders. In order to personalize and evaluate interventions aiming to improve upper limb function, it is essential to accurately assess the presence and extent of these impairments. Clinical assessments rely on experience-based observations, subjective evaluation, and ordinal scales, thus challenging a sensitive capture of intervention-induced changes in clinical trials. Novel robotic technologies promise sensitive and objective endpoints describing upper limb kinematic and kinetics during behavioural tasks. Over the last decades, we successfully developed, validated, and clinically applied such technologies in neurological disorders. The aim is to report on the feasibility, clinimetric properties, and clinical applicability of two complementary robotic assessments quantifying upper limb sensorimotor impairments. Methods: First, we relied on a haptic end-effector to record upper limb movement patterns and hand grip forces during a goal-directed pick-and-place task (Kanzler et al. 2020). Second, we custom-designed a robotic device and behavioural tasks providing precise stimuli to the index finger metacarpophalangeal joint, thereby allowing to study finger proprioception as well as motor and sensorimotor impairments (Zbytniewska et al. 2021). The recorded sensor data is analyzed with signal processing pipelines to generate objective digital health metrics describing movement quality (e.g., efficiency), grip force control (e.g., smoothness), and the response to well-controlled displacements (e.g., position matching error). Results: Feasibility of the assessments was established in persons with stroke, multiple sclerosis, or ataxia and matched able-bodied controls, revealing that the approaches are rapidly and easily applicable in a wide range of patients. For each platform, a core set of statistically optimal metrics was selected based on their test-retest reliability, measurement error, and discriminative power. Concurrent validity indicated low-moderate correlations with clinical scales, highlighting that the metrics provide novel, complementary information. By applying the metrics, we were able to reveal the presence of sensorimotor impairments and subtle longitudinal changes in persons that did not show abnormalities in clinical assessments. Conclusions: Robotic assessments are valuable tools to accurately and sensitively assess upper limb sensory, motor, and sensorimotor impairments in neurological disorders, thus opening novel avenues for evaluating clinical trials. References Kanzler CM, et al. A data-driven framework for selecting and validating digital health metrics: use-case in neurological sensorimotor impairments. npj Digit. Med. 2020;3(1):80. Zbytniewska M, et al. Reliable and valid robot-assisted assessments of hand proprioceptive, motor and sensorimotor impairments after stroke. J. Neuroeng. Rehabil. 2021;18(1):115.

Hand Swelling in an Adolescent.

Hand Swelling in an Adolescent.

Hand kinematics in osteoarthritis patients while performing functional activities

Purpose To identify the impact of kinematic limitations on hand osteoarthritis patients’ ability to perform daily living activities. Methods An experiment was performed on 33 patients and 32 healthy subjects. Active ranges of motion (AROM) of 16 hand joint angles were measured, together with scores of different hand tests of dexterity (Box and Block, Nine Hole Peg, Kapandji) and function (Sollerman Hand Function Test, SHFT). Functional ranges of motion (FROM) were recorded during SHFT tasks. Results by task are also reported. Results Patients’ AROM is limited in flexion of thumb carpometacarpal and interphalangeal, and finger metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints, and in palmar arch. Patients scored worse in gross dexterity and opposition, but only Kapandji score was correlated with AROM limitations. Pain is mostly reported in patients with limited extension of finger MCP and PIP joints. Patients used significantly different FROM in almost all the joints, and needed more time to accomplish the SHFT tasks. Conclusions AROM measurements can be used as indicators for early diagnosis. Patients use specific strategies to accomplish each task, arising from AROM limitations; some tasks with very extreme postures. The tasks where precision or force are required for thumb are the most affected ones. Implications for rehabilitation Active range of motion is an indicator for early hand osteoarthritis diagnosis. Patients' functional ranges are reduced, and thumb opposition and gross dexterity are hindered. Rehabilitation should focus especially on tasks requiring precision and thumb strength. Rehabilitation should favor the improvement of task completion times.

Flexohand: A Hybrid Exoskeleton-Based Novel Hand Rehabilitation Device.

Home-based hand rehabilitation has excellent potential as it may reduce patient dropouts due to travel, transportation, and insurance constraints. Being able to perform exercises precisely, accurately, and in a repetitive manner, robot-aided portable devices have gained much traction these days in hand rehabilitation. However, existing devices fall short in allowing some key natural movements, which are crucial to achieving full potential motion in performing activities of daily living. Firstly, existing exoskeleton type devices often restrict or suffer from uncontrolled wrist and forearm movement during finger exercises due to their setup of actuation and transmission mechanism. Secondly, they restrict passive metacarpophalangeal (MCP) abduction–adduction during MCP flexion–extension motion. Lastly, though a few of them can provide isolated finger ROM, none of them can offer isolated joint motion as per therapeutic need. All these natural movements are crucial for effective robot-aided finger rehabilitation. To bridge these gaps, in this research, a novel lightweight robotic device, namely “Flexohand”, has been developed for hand rehabilitation. A novel compliant mechanism has been developed and included in Flexohand to compensate for the passive movement of MCP abduction–adduction. The isolated and composite digit joint flexion–extension has been achieved by integrating a combination of sliding locks for IP joints and a wire locking system for finger MCP joints. Besides, the intuitive design of Flexohand inherently allows wrist joint movement during hand digit exercises. Experiments of passive exercises involving isolated joint motion, composite joint motions of individual fingers, and isolated joint motion of multiple fingers have been conducted to validate the functionality of the developed device. The experimental results show that Flexohand addresses the limitations of existing robot-aided hand rehabilitation devices.

Reliable and valid robot-assisted assessments of hand proprioceptive, motor and sensorimotor impairments after stroke

BackgroundNeurological injuries such as stroke often differentially impair hand motor and somatosensory function, as well as the interplay between the two, which leads to limitations in performing activities of daily living. However, it is challenging to identify which specific aspects of sensorimotor function are impaired based on conventional clinical assessments that are often insensitive and subjective. In this work we propose and validate a set of robot-assisted assessments aiming at disentangling hand proprioceptive from motor impairments, and capturing their interrelation (sensorimotor impairments).MethodsA battery of five complementary assessment tasks was implemented on a one degree-of-freedom end-effector robotic platform acting on the index finger metacarpophalangeal joint. Specifically, proprioceptive impairments were assessed using a position matching paradigm. Fast target reaching, range of motion and maximum fingertip force tasks characterized motor function deficits. Finally, sensorimotor impairments were assessed using a dexterous trajectory following task. Clinical feasibility (duration), reliability (intra-class correlation coefficient ICC, smallest real difference SRD) and validity (Kruskal-Wallis test, Spearman correlations rho with Fugl-Meyer Upper Limb Motor Assessment, kinesthetic Up-Down Test, Box & Block Test) of robotic tasks were evaluated with 36 sub-acute stroke subjects and 31 age-matched neurologically intact controls.ResultsEighty-three percent of stroke survivors with varied impairment severity (mild to severe) could complete all robotic tasks (duration: <15 min per tested hand). Further, the study demonstrated good to excellent reliability of the robotic tasks in the stroke population (ICC>0.7, SRD<30%), as well as discriminant validity, as indicated by significant differences (p-value<0.001) between stroke and control subjects. Concurrent validity was shown through moderate to strong correlations (rho=0.4-0.8) between robotic outcome measures and clinical scales. Finally, robotic tasks targeting different deficits (motor, sensory) were not strongly correlated with each other (rho le0.32, p-value>0.1), thereby presenting complementary information about a patient’s impairment profile.ConclusionsThe proposed robot-assisted assessments provide a clinically feasible, reliable, and valid approach to distinctly characterize impairments in hand proprioceptive and motor function, along with the interaction between the two. This opens new avenues to help unravel the contributions of unique aspects of sensorimotor function in post-stroke recovery, as well as to contribute to future developments towards personalized, assessment-driven therapies.

A Linkage Representation of the Human Hand Skeletal System Using CT Hand Scan Images

The present study proposed a method for establishing a linkage representation of the human hand skeletal system. Hand skeletons of 15 male subjects were reconstructed from computed tomography (CT) scans in 10 different postures selected from a natural hand-closing motion. The wrist joint center was estimated as the intersection of the centerline of the metacarpal of the middle finger and the distal wrist crease. The remaining joint centers were kinematically estimated based on the relative motion between the distal bone segment and the proximal bone segment of a given joint. A hand linkage representation was then formed by connecting the derived joint centers. Regression models for predicting internal hand link lengths using hand length as the independent variable were established. In addition, regression models for predicting the joint center coordinates of the thumb carpometacarpal (CMC) and finger metacarpophalangeal (MCP) joints using hand length or hand breadth were established. Our models showed higher R2 values and lower maximum standard errors than the existing models. The findings of the present study can be applied to hand models for ergonomic design and biomechanical modeling.

Design and Preliminary Performance Assessment of a Wearable Tremor Suppression Glove.

Approximately 25% of individualsliving with parkinsonian tremor do not respond to traditional treatments. Wearable tremor suppression devices (WTSD) provide an alternative approach, however, tremor in the fingers has not been given as much attention as tremor in the elbow and the wrist. Therefore, the objective of this study is to design a wearable tremor suppression glove that can suppress tremor simultaneously, but independently, in multiple hand joints without restricting the user's voluntary motion. A WTSD was designed for managing tremor in the index finger metacarpophalangeal (MCP) joint, thumb MCP joint, and the wrist. The prototype was tested and assessed on a participant living with parkinsonian tremor. The experimental evaluation showed an overall suppression of 73.1%, 80.7%, and 85.5% in resting tremor, 70.2%, 79.5%, and 81% in postural tremor, and 60.0%, 58.7%, and 65.0% in kinetic tremor in the index finger MCP joint, the thumb MCP joint, and the wrist, respectively. This first assessment of a WTSD for people living with Parkinson's disease provides confirmation of the feasibility of the approach. The next step requires a comprehensive validation on a broader population in order to evaluate the performance of the WTSD. This study demonstrates the feasibility of using a WTSD to manage hand and finger tremor. The device enriches the field of upper-limb tremor management, as the first WTSD for multiple joints of the hand.

Three concomitant locked finger metacarpophalangeal joints caused by degenerative metacarpal heads: Case report

A locked metacarpophalangeal joint (LMCP) is a rare condition often confused with trigger finger. Its causes are numerous and typically divided into two broad categories: acquired LMCP in younger patients, and degenerative LMCP in older patients. This pathology usually affects only one MCP. Even though several external reduction techniques have been described, the main risk of non-surgical reduction treatment is recurrence. Thus, its management is most often surgical. We report the case of a 60-year-old woman with 3 simultaneous LMCP (3rd, 4th, and 5th rays of the left hand) due to degenerative metacarpal heads. Surgical treatment was performed and found that locking was due to entrapment of the radial collateral ligament on metacarpal head osteophytes. Full extension was regained at the end of the surgery. The follow-up was uneventful, no recurrence occurred. This case highlights the need for careful examination to prevent medical and surgical wandering for a rare but well-described and easy to treat condition.

Influence of pitching grip on shoulder and elbow injuries in junior baseball players, focusing on hand length and the metacarpophalangeal joint angle

[Purpose] We investigated the relationship of pitching grip with hand length and index finger metacarpophalangeal joint angle. [Participants and Methods] A total of 650 junior baseball players divided into two groups according to whether they experienced shoulder or elbow pain were divided into two groups based on their pitching grip, i.e., those who held the ball with the ulnar side of the thumb and those who held it with the finger pad of the thumb. The metacarpophalangeal joint angle was measured while the participants held a ball. [Results] The average hand length was 16.3 ± 1.4 cm for those holding the ball with the ulnar side of the thumb and 15.8 ± 1.2 cm for those holding it with the finger pad of the thumb. Hand length and metacarpophalangeal angle were significantly greater in the group using the ulnar side of the thumb. The two groups showed no significant differences in the distribution of grip type or history of shoulder/elbow pain. The index finger metacarpophalangeal angle and shoulder/elbow pain were significantly lower in the pain group. [Conclusion] With respect to the pitching grip for junior baseball players, we recommend a slightly flexed rather than extended position with the metacarpophalangeal angle.