Hand Flexor Research Articles

Immediate Effects of Dermatomal Electrical Stimulation on Task-Oriented Movements in Patients with Chronic Hemiplegia

This study tested the hypothesis that performing task-oriented activities while receiving dermatomal electrical stimulation would induce significant improvement in hand functions. Ten chronic stroke patients were recruited. The subjects were able to understand verbal commands, and the spasticity of wrist and hand flexors was between grades 1 to 2 on the Modified Ashworth Scale (MAS). Three functional tasks were given to perform: to attach and detach velcro pegs, to move cones, and the Box and Block Test as a task. All tasks were randomly performed with and without dermatomal electrical stimulation. The surface electrodes for electrical stimulation were attached over the C8 dermatome and the intensity was adjusted to a level just below the threshold for a visible muscle contraction. An accelerometer was worn on the dorsal wrist of the subjects while performing cones task for analysis of the movement velocity. The results of all three tasks, and the accelerometer data showed that task-oriented movements combined with dermatomal electrical stimulation produced a significant immediate improvement in hand functions (p<0.05).

Microstimulation Activates a Handful of Muscle Synergies

Muscle synergies have been proposed as a mechanism to simplify movement control. Whether these coactivation patterns have any physiological reality within the nervous system remains unknown. Here we applied electrical microstimulation to motor cortical areas of rhesus macaques to evoke hand movements. Movements tended to converge toward particular postures, driven by synchronous bursts of muscle activity. Across stimulation sites, the muscle activations were reducible to linear sums of a few basic patterns-each corresponding to a muscle synergy evident in voluntary reach, grasp, and transport movements made by the animal. These synergies were represented nonuniformly over the cortical surface. We argue that the brain exploits these properties of synergies-postural equivalence, low dimensionality, and topographical representation-to simplify motor planning, even for complex hand movements.

Ultrasonographic assessment of longitudinal median nerve and hand flexor tendon dynamics in carpal tunnel syndrome

Ultrasonographic assessment of longitudinal median nerve and hand flexor tendon dynamics in carpal tunnel syndrome

Hand function in systemic sclerosis: A clinical and ultrasonographic study

Aim of the workTo evaluate hand impairment and functional disability in scleroderma patients using clinical and ultrasonographic (US) measures. Patients and methodsFifteen scleroderma patients and 10 age and sex-matched healthy controls were studied. Patients underwent clinical examination including modified Rodnan skin score. Hand function assessment included pinch and grip strength measurement, finger range of motion (ROM) assessment, Hand Mobility in Scleroderma (HAMIS) test and Hand Functional Index (HFI). Hand disability was assessed by Health Assessment Questionnaire (HAQ), Scleroderma HAQ Visual Analogue Scale (SHAQ VAS) and Cochin scale. US hand examination included measuring hand skin thickness, screening of the finger flexor and extensor tendons, measuring cartilage thickness of the 2nd MCP joint, anteroposterior thickness of the flexor retinaculum, and surface area of the median nerve. ResultsNine patients had healed digital ulcers while only one patient had active ulcers. Seven patients had arthralgia in the hand joints. The patients had a significant decrease in grip strength and finger ROM. By US, patients showed significant increase in hand skin thickness and flexor retinaculum thickness and a significant decrease in median nerve surface area. Hand disability measures showed variable significant correlations with pinch and grip strength and hand mobility measures which were significantly correlated with US skin thickness of the 2nd inter-metacarpal web space. ConclusionsHand disability in scleroderma was mainly related to impaired hand mobility and also diminished strength. The use of US in adjunct to clinical examination refines the evaluation of hand impairment in scleroderma.

Joint and tendon involvement in systemic lupus erythematosus: an ultrasound study of hands and wrists in 108 patients

To estimate the prevalence of, and identify factors associated with, hand and wrist US alterations in a large cohort of SLE patients. One hundred and eight consecutive SLE patients were recruited and classified according to arthropathy type and the musculoskeletal item of the British Isles Lupus Assessment Group (BILAG) 2004 score. US examinations were performed on hand and wrist flexor tendons, wrist extensor tendons, second and third MCP and wrist joints bilaterally using a multi-planar scanning technique. US examination showed joint involvement in 42/108 (38.8%) subjects, tendon involvement in 44/108 (40.7%) and both in 22/108 (20.3%). Patients with rhupus syndrome (n = 8) carried a higher incidence of inflammatory changes (87%) and erosions (87%) compared with the six with Jaccoud's arthropathy (50% and 17%, respectively) and the 94 with non-deforming X-ray non-erosive arthropathy (37% and 21%, respectively). Power Doppler signal was prevalent in patients scoring A (n = 4) or B (n = 9) on the musculoskeletal item of the BILAG 2004, and was significantly more frequent at the joint (92%) and tendon (54%) level than in the 26 patients scoring C (19%, P = 0.0007 and 15%, P = 0.016, respectively) and in the 69 scoring D (3%, P < 0.0001 and 3%, P < 0.0001). US changes in patients who scored C or D were more expressed at the tendon level (50% and 29%, respectively) than at the joint level (35% and 9%, respectively). The picture of musculoskeletal US in SLE depends on arthropathy subtype and disease activity. US examination could be a valid and reliable tool to monitor musculoskeletal features and therapeutic outcomes in SLE patients.

Ultrasonographic assessment of longitudinal median nerve and hand flexor tendon dynamics in carpal tunnel syndrome

Changes in subsynovial connective tissue (SSCT) in carpal tunnel syndrome (CTS) patients may result in altered dynamics; consequently, quantification of these dynamics might support objective diagnosis of CTS. We measured and compared longitudinal excursion of the flexor digitorum superficialis and profundus tendons, the median nerve, and the SSCT between the most and least affected hands of 51 CTS patients during extension-to-fist motion. Median nerve and flexor digitorum superficialis tendon excursions in the most affected hands were smaller than in the least affected hands of the same patients, whereas the excursions of the flexor digitorum profundus were larger. Based on these excursions, logistic regression models classified between 67% and 86% of the hands correctly as having CTS. The altered hand dynamics in CTS patients may have implications for the pathophysiology and clinical evaluation of CTS, and ultrasound-based classification models may further support the diagnosis of CTS.

Ultrasonographic Assessment of Flexor Tendon Mobilization: Effect of Different Protocols on Tendon Excursion

Different mobilization protocols have been proposed for rehabilitation after hand flexor tendon repair to provide tendon excursion sufficient to prevent adhesions. Several cadaver studies have shown that the position of the neighboring fingers influences tendon excursions of the injured finger. We hypothesized that the positions of adjacent fingers influence the long finger flexor digitorum profundus tendon excursion, measured both absolutely and relative to the surrounding tissue of the tendon. Long finger flexor digitorum profundus tendon excursions and surrounding tissue movement were measured in zone V in eleven healthy subjects during three different rehabilitation protocols and two experimental models: (1) an active four-finger mobilization protocol, (2) a passive four-finger mobilization protocol, (3) a modified Kleinert mobilization protocol, (4) an experimental modified Kleinert flexion mobilization model, and (5) an experimental modified Kleinert extension mobilization model. Tendon excursions were measured with use of a frame-to-frame analysis of high-resolution ultrasound images. The median absolute long finger flexor digitorum profundus tendon excursions were 23.4, 17.8, 10.0, 13.9, and 7.6 mm for the active four-finger mobilization protocol, the passive four-finger mobilization protocol, the modified Kleinert mobilization protocol, the experimental modified Kleinert flexion mobilization model, and the experimental modified Kleinert extension mobilization model, respectively, and these differences were all significant (p ≤ 0.041). The corresponding relative flexor digitorum profundus tendon excursions were 11.2, 8.5, 7.2, 10.4, and 5.6 mm. Active four-finger mobilization protocol excursions were significantly (p = 0.013) greater than passive four-finger mobilization protocol excursions but were not significantly greater than experimental modified Kleinert flexion mobilization model excursions (p =0.213). The present study demonstrated large and significant differences among the different rehabilitation protocols and experimental models in terms of absolute and relative tendon displacement. More importantly, the present study clearly demonstrated the influence of the position of the adjacent fingers on the flexor tendon displacement of the finger that is mobilized.

Hand Robotics Rehabilitation: Feasibility and Preliminary Results of a Robotic Treatment in Patients with Hemiparesis

Background. No strongly clinical evidence about the use of hand robot-assisted therapy in stroke patients was demonstrated. This preliminary observer study was aimed at evaluating the efficacy of intensive robot-assisted therapy in hand function recovery, in the early phase after a stroke onset. Methods. Seven acute ischemic stroke patients at their first-ever stroke were enrolled. Treatment was performed using Amadeo robotic system (Tyromotion GmbH Graz, Austria). Each participant received, in addition to inpatients standard rehabilitative treatment, 20 sessions of robotic treatment for 4 consecutive weeks (5 days/week). Each session lasted for 40 minutes. The exercises were carried out as follows: passive modality (5 minutes), passive/plus modality (5 minutes), assisted therapy (10 minutes), and balloon (10 minutes). The following impairment and functional evaluations, Fugl-Meyer Scale (FM), Medical Research Council Scale for Muscle Strength (hand flexor and extensor muscles) (MRC), Motricity Index (MI), and modified Ashworth Scale for wrist and hand muscles (AS), were performed at the beginning (T0), after 10 sessions (T1), and at the end of the treatment (T2). The strength hand flexion and extension performed by Robot were assessed at T0 and T2. The Barthel Index and COMP (performance and satisfaction subscale) were assessed at T0 and T2. Results. Clinical improvements were found in all patients. No dropouts were recorded during the treatment and all subjects fulfilled the protocol. Evidence of a significant improvement was demonstrated by the Friedman test for the MRC (P < 0.0123). Evidence of an improvement was demonstrated for AS, FM, and MI. Conclusions. This original rehabilitation treatment could contribute to increase the hand motor recovery in acute stroke patients. The simplicity of the treatment, the lack of side effects, and the first positive results in acute stroke patients support the recommendations to extend the clinical trial of this treatment, in association with physiotherapy and/or occupational therapy.

Isometric Force Development of Some Muscle Groups in Athletes

In a large sample of both male and female athletes, subdivided by age and sex, a development curve of isometric muscule force (F) was analyzed for hand flexors, upper-body flexors and extensors, and knee extensors (PDS). A sample of 1,857 male and 1,009 female athletes, aged 8-30 years, subdivided by their age and sex, was used to measure the mean values of isometric muscle force of certain muscle groups by way of 5 topologically defined tests. Based on the results, isometric muscle force (F) development curves are shown and analyzed for the right-hand and left-hand (PLS) flexors, upper-body flexors (PTR), upper-body extensors (OTR), and knee extensors (ONO). The application of certain statistical programs gave rise to equations of the relationship between isometric force and age. The maximum mean value of PLS was chosen as the reference value or "the gold standard," with which PTR, OTR, and ONO were subsequently compared. The relationships were 1:1:1:2.8:5.9 (for male athletes), and 1:1:1.3:3.2:5.2 (for female athletes). The newly derived relationship was recognized as "the canon." The results may have practical application in athletes' fitness and conditioning. Every topologically defined muscle force has its own patterns and rules that should be closely followed in the training process, because any generalization may lead to false conclusions.

Cognitive task performance causes impaired maximum force production in human hand flexor muscles

The purpose of this study was to investigate effects of demanding cognitive task performance on intermittent maximum voluntary muscle contraction (MVC) force production. Participants performed either a modified Stroop or control task for 22min. After the first min and at 3-min intervals thereafter, participants rated fatigue, perceived mental exertion and performed a 4-s MVC handgrip squeeze. A mixed ANOVA showed a significant interaction, F(7, 259)=2.43, p=.02, with a significant linear reduction in MVC force production over time in the cognitively depleting condition (p=.01) and no change for controls. Ratings of perceived mental exertion, F(7, 252)=2.39, p<.05, mirrored the force production results with a greater linear increase over time in the cognitive depletion condition (p<.001) compared to controls. Findings support current views that performance of cognitively demanding tasks diminishes central nervous system resources that govern self-regulation of physical tasks requiring maximal voluntary effort.

The “50% Rule” in Arthroscopic and Orthopaedic Surgery

The “50% rule” is used commonly to guide treatment of partial tears of tendons and ligaments. The purpose of this study was to examine the history and validity of the 50% rule in arthroscopic and orthopaedic surgery. A PubMed search yielded 1,039 articles that were reviewed to identify the origins of the 50% rule for hand flexor tendon lacerations, partial anterior cruciate ligament tears, partial-thickness rotator cuff tears, and partial injuries of the long head of the biceps tendon. The rule appears to have evolved from the hand literature toward somewhat arbitrary application for other orthopaedic conditions. Little scientific information is available to support the 50% rule for these disparate entities. In our Level V opinion, the 50% rule allows surgeons to use subjective discretion in the management of prevalent orthopaedic conditions but there is very little scientific support for this ubiquitous decision-making criterion.

Moment arms of the human digital flexors

For the extrinsic hand flexors (flexor digitorum profundus, FDP; flexor digitorum superficialis, FDS; flexor pollicis longus, FPL), moment arm corresponds to the tendon's distance from the center of the metacarpalphalangeal (MP), proximal interphalangeal (PIP), or distal interphalangeal (DIP) joint. The clinical value of establishing accurate moment arms has been highlighted for biomechanical modeling, the development of robotic hands, designing rehabilitation protocols, and repairing flexor tendon pulleys ( Brand et al., 1975; An et al., 1983; Thompson and Giurintano, 1989; Deshpande et al., 2010; Wu et al., 2010). In this study, we define the moment arms for all of the extrinsic flexor tendons of the hand across all digital joints for all digits in cadaveric hands.

Upper Limb Nerve Injury - Baseball

HISTORY: A 21 year old right-handed baseball player suffered a fracture of his left 4th metacarpal after being struck by a fastball. He underwent surgical correction of his injury and did not play baseball for the next four weeks. He then returned to play for two weeks without incident. At this time the patient took a two week vacation and upon return to training he experienced numbness in the ulnar distribution of his right hand, an "electric sensation" into his hand from his elbow when throwing, and grip incoordination. The only change to his training regimen was the addition of triceps push-ups for the first time, but he indicated that he was asymptomatic while doing them. PHYSICAL EXAMINATION: Weakness of the right ulnar hand intrinsic muscles and flexor digitorum profundus at the ring and small fingers was noted. Wrist flexion was minimally affected and strength was normal in all other areas. Decreased appreciation to light touch in the ulnar distribution of the right hand was also observed. No significant deformity was noted about the elbow and no snapping or popping was evident on routine examination. This phenomenon was appreciated, however, while the patient performed triceps push-ups. DIFFERENTIAL DIAGNOSIS Ulnar nerve entrapment at the elbow Ulnar neuropathy at the wrist C8-T1 radiculopathy Lower trunk/medial cord brachial plexopathy Neurogenic thoracic outlet syndrome TEST AND RESULTS: Electrodiagnosis: Electrodiagnostic studies demonstrated a moderate ulnar neuropathy with neurapraxic block just proximal to the medial epicondyle. Musculoskeletal ultrasound: High frequency ultrasound demonstrated proximal swelling of the right ulnar nerve just proximal to the medial epicondyle. Dramatic subluxation of the medial triceps tendon and ulnar nerve was observed over the medial epicondyle while the patient performed triceps push-ups. This was not seen during routine flexion/extension of the elbow. FINAL WORKING DIAGNOSIS: Dynamic subluxation of the triceps under load causing Snapping Triceps Syndrome with resultant Ulnar Neuropathy at the elbow. TREATMENT AND OUTCOMES: Recognition of this syndrome with avoidance of triceps push-ups and similar repetitive motions at the elbow led to a nearly complete resolution of symptoms and successful return to competitive baseball within four weeks.

Monitoring hand flexor fatigue in a 24-h motorcycle endurance race

Motorcycle riders must endure high levels of muscle tension for long periods of time, especially in their arms and forearms, when steering and using handlebar controls. Because the right hand operates the gas handle and front brakes, the present research focuses on fatigue in the right hand flexors. Ten adult riders, aged 32.5 ± 5.5 years, volunteered to participate in this study. During the 24 h race each rider, on completion of a relay stage, visited the assessment box to do the following handgrip test sequence: (1) 10 s of EMG recording at rest, (2) one 3-s maximal voluntary contraction (MVC), (3) 1 min rest interval and (4) 50% MVC maintained during 10 s. EMG amplitude (MP: μV) and median and mean frequency (MF and MPF: Hz) over the superficial finger flexors were recorded during the whole handgrip test sequence with adhesive surface electrodes. MVC values were maintained during the first two relays (50–60 min duration in total) and dropped gradually thereafter ( p < 0.01). During the monitoring of the 50% MVC, mean amplitude increased ( p = 0.024) while median and mean frequency tended to decrease. These results suggest fatigue is produced in motorcycle riders in a 24 h race. However, the expected reduction of EMG frequency was not confirmed given to a potentially large variability.

Shooting dynamics in archery: A multidimensional analysis from drawing to releasing in male archers

The purpose of this study is to investigate the relationships between physiological and mechanical dynamics during arrow releasing in archery with the quality of the arrow shot. Four elite male archers were involved in this study. Mechanical clicker reaction time (MCRT), Integrated Electromygraphic % (IEMG %) activity of hand flexor and extensor, deltoid and trapezius were recorded at a sampling frequency of 600Hz. Aiming behaviours, aiming time, total drawing time (TDT) and full drawing time (FDT) were calculated by the first act in trapezius. Postural sway, aiming sway and body weight shifts, changes in the posture of archers toward sideways (DX) and front-back (DY), decrease in the body weight (DBW) on legs were recorded at the same sampling rate using force plates for every arrow of archers. All the measurement methods were synchronized with each other and referenced to the clicker fall. Subjects completed 30 arrows on an 18m range constructed indoors. Statistical analysis was conducted using SPSS 12.0. It has been found that performance of male archers varies according to flexor muscle one second prior to clicker falls and that the performance increases when the muscular activity of flexor and deltoid muscles decreases. It has been stated that archers have better shots as the posture sways towards right-left within the period of holding the bow tight and as the drawing time decreases. In conclusion, archers MCRT is shorter for high performance. As muscle activity decreases, performance increases. Aiming sways on the target towards right-left, up and down and postural sways during releasing towards sideways and anterio-posterior affect performance. Drawing time may change with performance and which is affected by shift in the body weight especially after releasing.

Psychometric characteristics of Duruoz Hand Index in patients with traumatic hand flexor tendon injuries

Introduction. The aim of the study was to assess reliability, validity and responsiveness of Duruoz Hand Index (DHI), which has been developed for evaluation of activity limitation in rheumatoid arthritis in patients with traumatic hand flexor tendon injuries.Material and method. Sixty-five patients older than 16 years who underwent surgical intervention after flexor tendon injuries were enrolled. Reliability was assessed by internal consistency (with Cronbach's-α) and test-retest intraclass correlation coefficient (ICC). Construct validity was estimated correlating the scale with the DASH and VAS-hd. Also responsiveness was estimated using standardised response mean (SRM) and effect size (ES).Result. Mean age of the patients was 30.25 ± 11.07 years and totally 140 fingers were evaluated. Cronbach's-α and ICC values of DHI were found to be 0.87 and 0.99, respectively. In validation study, highly significant correlation was detected between DHI with DASH and VAS-hd (r == 0.86, r == 0.54, p < 0.0001, respectively). SRM values and ES values (excepting workplaces subgroup score) were higher than 0.80 for total and all subgroup scores.Conclusion. DHI is a reliable, valid questionnaire to assess hand-related activity limitation in patients with traumatic hand flexor tendon injuries. Also, due to its high level responsiveness DHI can be used for assessing the clinical course of the traumatic hand flexor tendon injured patient.

Corticospinal interaction during isometric compensation for modulated forces with different frequencies

BackgroundDuring isometric compensation of modulated low-level forces corticomuscular coherence (CMC) has been shown to occur in high-beta or gamma-range. The influence of the frequency of force modulation on CMC has up to now remained unexplored. We addressed this question by investigating CMC, motor performance, and cortical spectral power during a visuomotor task in which subjects had to compensate a modulated force of 8% of the maximum voluntary contraction exerted on their right index finger. The effect of three frequencies of force modulation (0.6, 1.0 and 1.6 Hz) was tested. EEG, EMG from first dorsal interosseus, hand flexor and extensor muscles, and finger position were recorded in eight right-handed women.ResultsFive subjects showed CMC in gamma- (28-45 Hz) and three in beta-range (15-30 Hz). Beta- and gamma-range CMC and cortical motor spectral power were not modulated by the various frequencies. However, a sharp bilateral CMC peak at 1.6 Hz was observed, but only in the five gamma-range CMC subjects. The performance error increased linearly with the frequency.ConclusionsOur findings suggest that the frequency of force modulation has no effect on the beta- and gamma-range CMC during isometric compensation for modulated forces at 8% MVC. The beta- and gamma-range CMC may be related to interindividual differences and possibly to strategy differences.

Effects of Font Size on Muscle Activity

A laboratory study was conducted to determine the effect of display font size on muscle activity, using surface electromyography (SEMG) and Rapid Upper Limb Assessment (RULA). The study showed that volunteers performing the experiment on small font size increased left hand flexor and neck extensor muscles activity. There was also a significant difference in RULA grand scores based on posture angle measures between the three tasks that subjects performed. In addition, there was an effect of time on upper body posture and subjective measures. There was no impact of font size on the dominant hand deltoid and trapezius, or left and right hand extensor muscles. In general, the results suggest that software developers should be sensitive to font size while designing software. The results also suggest that computer users should have better knowledge regarding the benefits of increasing the font size on their displays.

Rupture of the Flexor Digitorum Profundus Tendon Caused by Closed Blunt Trauma

Rupture of the flexor tendon due to closed direct trauma is rare ( 1 Hofmeister E.P. Craven Jr, C.E. Zone I rupture of the flexor digitorum profundus tendon caused by blunt trauma: a case report. J Hand Surg [Am]. 2008; 33: 247-249 Abstract Full Text Full Text PDF PubMed Scopus (9) Google Scholar ). Generally, flexor tendon injuries are diagnosed easily. However, pain, swelling, a closed wound, and non-cooperation can make the diagnosis more difficult ( 2 Wang P.T. Bonavita J.A. DeLone Jr, F.X. et al. Ultrasonic assistance in the diagnosis of hand flexor tendon injuries. Ann Plast Surg. 1999; 42: 403-407 Crossref PubMed Scopus (30) Google Scholar ).

Musculoskeletal sonography in juvenile systemic lupus erythematosus

To demonstrate the role of sonography in depicting periarticular changes in juvenile systemic lupus erythematosus (SLE) and to find out whether certain tendons in juvenile SLE patients were different from those of healthy controls. Thirty juvenile SLE patients (27 female, 3 male) were recruited for this study. Sonographic evaluations were performed in the knee, ankle, elbow, wrist, and metacarpophalangeal (MCP) joints on the nondominant sides of the individuals. For comparison, 32 healthy volunteers were included as a control group. Knee effusion was observed more frequently in the juvenile SLE group compared with the control group (P = 0.00). When tendon thickness measurements were compared between the groups, flexor and extensor tendons of the third finger (at MCP joint level) of juvenile SLE patients were found to be thinner (P = 0.04 and P = 0.03, respectively). Tendon thickness values did not correlate with disease duration or SLE disease activity index scores (P > 0.05). The main findings of our study were relevant with 1) increased involvement of the knee, ankle, hand extensor tendons, wrist, elbow, and hand flexor tendons (in decreasing order of frequencies) in juvenile SLE, and 2) decreased extensor/flexor tendon thicknesses in the hands of juvenile SLE patients. Physicians should be aware of the potentially disabling scenario of tendon pathologies. Defining the extent of joint and tendon pathologies in juvenile SLE may guide us in the management of the disease.