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Concept: Wrist

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INTRODUCTION: We present the case of a patient with extensor carpi ulnaris tendon subluxation who was first treated for distal radioulnar joint sprain. CASE PRESENTATION: A 25-year-old Caucasian man was seen at our policlinic one month after he had fallen on his outstretched hand. A diagnosis of extensor carpi ulnaris subluxation was made clinically but we also had the magnetic resonance imaging scan of the patient’s wrist which displayed an increased signal on T2-weighted images consistent with inflammation around the extensor carpi ulnaris tendon. The extensor carpi ulnaris tendon was found to be dislocating during supination and relocating during pronation. The sheath was reconstructed using extensor retinaculum due to attenuation of subsheath. CONCLUSION: There was no recurrent dislocation of the extensor carpi ulnaris tendon of the patient at his last follow up 12 months after the operation.

Concepts: Nuclear magnetic resonance, Magnetic resonance imaging, Wrist, Joint dislocation, Distal radioulnar articulation, Extensor carpi ulnaris muscle, Extensor carpi radialis longus muscle, Proximal radioulnar articulation

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Cross education (CE) occurs after unilateral training whereby performance of the untrained contralateral limb is enhanced. A few studies have shown that CE can preserve or “spare” strength and size of an opposite immobilized limb, but the specificity (i.e., trained homologous muscle and contraction type) of these effects is unknown. The purpose was to investigate specificity of CE “sparing” effects with immobilization. The nondominant forearm of 16 participants was immobilized with a cast, and participants were randomly assigned to a resistance training (eccentric wrist flexion, 3 times/week) or control group for 4 weeks. Pre- and posttesting involved wrist flexors and extensors eccentric, concentric and isometric maximal voluntary contractions (via dynamometer), muscle thickness (via ultrasound), and forearm muscle cross-sectional area (MCSA; via peripheral quantitative computed tomography). Only the training group showed strength preservation across all contractions in the wrist flexors of the immobilized limb (training: -2.4% vs. control: -21.6%; P = 0.04), and increased wrist flexors strength of the nonimmobilized limb (training: 30.8% vs. control: -7.4%; P = 0.04). Immobilized arm MCSA was preserved for the training group only (training: 1.3% vs. control: -2.3%; P = 0.01). Muscle thickness differed between groups for the immobilized (training: 2.8% vs. control: -3.2%; P = 0.01) and nonimmobilized wrist flexors (training: 7.1% vs. control: -3.7%; P = 0.02). Strength preservation was nonspecific to contraction type ( P = 0.69, [Formula: see text] = 0.03) yet specific to the trained flexors muscle. These findings suggest that eccentric training of the nonimmobilized limb can preserve size of the immobilized contralateral homologous muscle and strength across multiple contraction types. NEW & NOTEWORTHY Unilateral strength training preserves strength, muscle thickness, and muscle cross-sectional area in an opposite immobilized limb. The preservation of size and strength was confined to the trained homologous muscle group. However, strength was preserved across multiple contraction types.

Concepts: Muscle, Muscle contraction, Strength training, Forearm, Upper limb, Wrist, Isometric exercise, Preservation

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The boom in computer use and concurrent high rates in musculoskeletal complaints and carpal tunnel syndrome (CTS) among users have led to a controversy about a possible link. Most studies have used cross-sectional designs and shown no association. The present study used longitudinal data from two large complementary cohorts to evaluate a possible relationship between CTS and the performance of computer work.

Concepts: Cross-sectional study, Syndromes, Computer, Computer program, Wrist, Carpal tunnel, Carpal tunnel syndrome, Median nerve

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A previous ultrasound study showed inflammation around the extensor pollicis longus tendon and surrounding structures at 6 weeks after manipulation, with or without pin fixation, and immobilization for distal radius fracture. Ultrasound examination after plating of distal radius fracture followed by early active mobilization of the wrist showed a short-lived inflammatory response, evident at 2 weeks but not at 6 weeks, around the extensor pollicis longus tendon (26 wrists examined) and flexor pollicis longus tendon (18 wrists examined). Early active mobilization of the wrist appears to limit the duration of inflammation around these tendons.

Concepts: Flexor digitorum profundus muscle, Wrist, Distal radius fracture, Flexor pollicis longus muscle, Extensor pollicis brevis muscle, Carpal tunnel, Flexor pollicis brevis muscle, Extensor pollicis longus muscle

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Previous research has revealed significant size differences between human male and female carpal bones but it is unknown if there are significant shape differences as well. This study investigated sex-related shape variation and allometric patterns in five carpal bones that make up the radiocarpal and midcarpal joints in modern humans. We found that many aspects of carpal shape (76% of all variables quantified) were similar between males and females, despite variation in size. However, 10 of the shape ratios were significantly different between males and females, with at least one significant shape difference observed in each carpal bone. Within-sex standard major axis regressions (SMA) of the numerator (i.e., the linear variables) on the denominator (i.e., the geometric mean) for each significantly different shape ratio indicated that most linear variables scaled with positive allometry in both males and females, and that for eight of the shape ratios, sex-related shape variation is associated with statistically similar sex-specific scaling relationships. Only the length of the scaphoid body and the height of the lunate triquetrum facet showed a significantly higher SMA slope in females compared with males. These findings indicate that the significant differences in the majority of the shape ratios are a function of subtle (i.e., not statistically significant) scaling differences between males and females. There are a number of potential developmental, functional, and evolutionary factors that may cause sex-related shape differences in the human carpus. The results highlight the potential for subtle differences in scaling to result in functionally significant differences in shape. Anat Rec, 2013. © 2012 Wiley Periodicals, Inc.

Concepts: Human, Male, Female, Wrist, Carpus, Lunate bone, Trapezoid bone, Scaphoid bone

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Following two decades of design and clinical research on robot-mediated therapy for the shoulder and elbow, therapeutic robotic devices for other joints are being proposed: several research groups including ours have designed robots for the wrist, either to be used as stand-alone devices or in conjunction with shoulder and elbow devices. However, in contrast with robots for the shoulder and elbow which were able to take advantage of descriptive kinematic models developed in neuroscience for the past 30 years, design of wrist robots controllers cannot rely on similar prior-art: wrist movement kinematics has been largely unexplored. This study aimed at examining speed profiles of fast, visuallyevoked, visually-guided, target-directed human wrist pointing movements. Thirteen hundred ninety-eight (1398) trials were recorded from seven unimpaired subjects who performed centerout flexion/extension and abduction/adduction wrist movements and fitted with nineteen models previously proposed for describing reaching speed profiles. A nonlinear, least-squares optimization procedure extracted parameters sets that minimized error between experimental and reconstructed data. Models performances were compared based on their ability to reconstruct experimental data. Results suggest that the support-bounded lognormal is the best model for speed profiles of fast, wrist pointing movements. Applications include design of control algorithms for therapeutic wrist robots and quantitative metrics of motor recovery.

Concepts: Medicine, Human anatomy, Velocity, Kinematics, Joints, Wrist, Inverse kinematics

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OBJECTIVE: To compare ultrasound measurement of median nerve cross-sectional area (CSA) at different anatomical landmarks and to assess the value of power Doppler signals within the median nerve for diagnosis of carpal tunnel syndrome (CTS). METHODS: A prospective study of 135 consecutive patients with suspected CTS undergoing two visits within 3 months. A final diagnosis of CTS was established by clinical and electrophysiological findings. CSA was sonographically measured at five different levels at forearm and wrist; and CSA wrist to forearm ratios or differences were calculated. Intraneural power Doppler signals were semiquantitatively graded. Diagnostic values of different ultrasound methods were compared by receiver operating characteristic curves using SPSS. RESULTS: CTS was diagnosed in 111 (45.5%) wrists; 84 (34.4%) had no CTS and 49 (20.1%) were possible CTS cases. Diagnostic values were comparable for all sonographic methods to determine median nerve swelling, with area under the curves ranging from 0.75 to 0.85. Thresholds of 9.8 and 13.8 mm(2) for the largest CSA of the median nerve yielded a sensitivity of 92% and a specificity of 92%. A power Doppler score of 2 or greater had a specificity of 90% for the diagnosis of CTS. Sonographic median nerve volumetry revealed a good reliability with an intraclass correlation coefficient of 0.90 (95% CI 0.79 to 0.95). CONCLUSIONS: Sonographic assessment of median nerve swelling and vascularity allows for a reliable diagnosis of CTS. Determination of CSA at its maximal shape offers an easily reproducible tool for CTS classification in daily clinical practice.

Concepts: Diagnosis, Medical ultrasonography, Wrist, Ulnar nerve, Carpal tunnel, Carpal tunnel syndrome, Median nerve, Carpus

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PURPOSE: The purpose of this study was to determine functional and subjective results of patients who received arthroscopic debridement for their TFCC Palmer 1B lesions and to compare their results with those of arthroscopic suture repair. METHODS: Between March 2007 and August 2011, 36 patients were diagnosed with Palmer type 1B tears and underwent arthroscopic debridement. 31 patients (15 males and 16 females) were followed up for an average of 26.7 months (±17.4 months) postoperatively. Their average age was 36.7 years (±12.7 years). Follow-up included the determination of range of motion (ROM), grip strength, pain, and wrist scores (modified Mayo wrist score (MMWS), Disabilities of the Arm, Shoulder and Hand questionnaire (DASH score)). RESULTS: Postoperative ROM averaged 99.2 % for the extension/flexion arc, 95.5 % for the radial/ulnar deviation arc, and 99.4 % for the pronation/supination arc of motion when compared with the contralateral wrist. The MMWS was rated excellent in 48 % of patients, good in 39 %, fair in 13 %, and poor in 0 %. The average DASH score was 17.02 (±14.92). There was a significant reduction in pain. The grip strength was 96.7 % (±15.8), pulp-to-pulp pinch 101.9 % (±17.4), and the ulnar variance -0.12 ± 1.69 mm. CONCLUSIONS: Arthroscopic debridement of Palmer type 1B lesions in stable DRUJ yields satisfactory to excellent results. Our study showed similar results compared with the studies of arthroscopic suture repair with shorter postoperative care and fewer complications.

Concepts: Forearm, Wrist, Arthroscopy, Objective pronoun, Grip strength, Distal radioulnar articulation, Triangular fibrocartilage

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BACKGROUND: Contradictory reports have been published regarding the association of Carpal Tunnel Syndrome (C.T.S) and the use of computer keyboard. Previous studies did not take into account the cumulative exposure to keyboard strokes among computer workers. The aim of the present study was to investigate the association between cumulative keyboard use (keyboard strokes) and C.T.S. METHODS: Employees (461) of a Governmental data entry & processing unit accepted to participated in a cross-sectional study (response rate: 84.1%). A questionnaire was distributed to the participants with the aim to obtain information on socio-demographics, and risk factors for CTS. The participants were examined for signs and symptoms related to CTS and were asked about previous history or surgery for CTS. The cumulative amount of the keyboard strokes per worker per year was calculated by the use of payroll’s registry. Two case definitions for CTS were used. The first included subjects with positive personal history of CTS/surgery for CTS while the second included subjects that belonged to the first case definition plus cases identified through clinical examination. RESULTS: Multivariate analysis indicated-for both case definitions- that those employees with high cumulative exposure to keyboard strokes were at increased risk of CTS (case definition A: OR=2.23;95% CI=1.09-4.52 and case definition B: OR=2. 41; 95%CI=1.36-4.25). A dose response pattern between cumulative exposure to keyboard strokes and CTS has been revealed (p<0.001). CONCLUSIONS: The present study indicated a possible association between cumulative exposure to keyboard strokes and the development of CTS. Cumulative exposure to key-board strokes would be taken into account as an exposure indicator regarding exposure assessment of computer workers. Further research is needed in order to test the results of the current study and assess causality between cumulative keyboard strokes and development of CTS.

Concepts: Epidemiology, The Canon of Medicine, Avicenna, Wrist, Carpal tunnel, Carpal tunnel syndrome, Median nerve, Keystroke logging

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The effectiveness of acupuncture for managing carpal tunnel syndrome is uncertain, particularly in patients already receiving conventional treatments (e.g., splinting). We aimed to assess the effects of electroacupuncture combined with splinting.

Concepts: Randomized controlled trial, Effectiveness, Syndromes, Acupuncture, Wrist, Carpal tunnel, Carpal tunnel syndrome, Median nerve