A posterior tibial slope angle over 12 degrees is critical to epiphyseal fracture of the proximal tibia: Three-dimensional finite element analysis.

Introduction: The effects of the proximal tibial slope angle on the proximal tibial epiphysis remain unknown. To elucidate those effects, we investigated the strain distribution in proximal tibial epiphysis with different proximal tibial slope angles and proximal tibial epiphysis closure periods using finite element analysis. Materials and methods: The finite element models of the proximal tibia were reconstructed from CT images and consisted of cancellous/cortical bone and epiphyseal plate. The variations in proximal tibial slope angle (range: 6-16°) and four closure variations in proximal tibial epiphysis (open, semi-open, semi-closed, and closed) were prepared. The loading force on the medial and lateral joint surface, and the tensile force by the patellar tendon were applied to the models, and the distal area of the tibia was fixed. The ratio of the equivalent strain in semi-open/semi-closed proximal tibial epiphysis to the strain in open proximal tibial epiphysis on different proximal tibial slope angles were calculated. Results: The strain ratio between the semi-open/semi-closed and open proximal tibial epiphysis models indicated significant differences between 6 or 8° of proximal tibial slope angle and 12, 14, and 16° of proximal tibial slope angle models. In the increased proximal tibial slope angle model, a hoop-shaped strain in the closing proximal tibial epiphysis was found, and the maximum strain was found in the tibial tubercle. Discussion: During epiphyseal closure, adolescents with an increased proximal tibial slope angle over 12° are significantly at risk for suffering from proximal tibial epiphyseal fractures compared with those under 10°.

The Morel-Lavallée Lesion: Review and Update on Diagnosis and Management.

Morel-Lavallée lesion is a closed soft tissue degloving injury usually associated with high-velocity trauma. It most commonly occurs in the thigh, hip, and pelvis. Because such lesions are prone to a missed or delayed diagnosis, it may present a potential risk of infection at the fracture site once it progresses. Therefore, timely identification and management of Morel-Lavallée lesion is crucial. Moreover, there are no relevant guidelines for the treatment of Morel-Lavallée lesion. Based on the above facts, we reviewed the etiology, epidemiology, pathophysiology, clinical presentation, imaging features, treatment, prognosis, and complications of Morel-Lavallée lesion with the aim of providing a comprehensive overview of Morel-Lavallée lesion, increasing awareness of this injury among orthopaedic surgeons, and thus providing a management algorithm that can be applied to this injury.

Degradation of starch in pasta induced by extrusion below gelatinization temperature.

The structural deformation of starch during pasta extrusion leads to varied effects on pasta quality. We investigated the impact of shearing force on the starch structure of pasta and pasta quality by varying the screw speed (100, 300, 500 and 600 rpm) with a temperature range of 25 to 50 ℃ in increments of 5 ℃, from the feeding zone to the die zone. The higher screw speeds were associated with more specific mechanical energy input (157, 319, 440, and 531 kJ/kg for pasta produced at 100, 300, 500 and 600 rpm, respectively), resulting in a lower pasting viscosity (1084, 813, 522 and 480 mPa·s for pasta produced at 100, 300, 500 and 600 rpm, respectively) in the pasta due to the loss of starch molecular order and crystallinity. Size-exclusion chromatography revealed that pasta produced at 600 rpm screw speed had a lower amylopectin size distribution which indicated molecular breakdown during extrusion. Pasta produced at 600 rpm had higher in vitro starch hydrolysis (both raw and cooked) than the pasta made at 100 rpm. The research provides relationship of how the screw speed can be manipulated to design pasta with varied texture and nutritional functionality.

Talon Noir: A Case Report and Literature Review.

Talon noir is an asymptomatic, self-limiting, dermatological condition that is most commonly seen in young athletes and mountain climbers. Histologically, the characteristic findings are intraepidermal hemorrhage and fluid collection due to shearing forces. Here, we report an interesting case in an elderly female, which mimicked acral melanoma clinically and alerted us to do a biopsy for confirmation.

Ten-year incidence and treatment outcomes of closed degloving injuries (Morel-Lavallee lesions) in a level 1 trauma centre.

INTRODUCTION: Morel-Lavallée lesions (MLL), also referred to as closed degloving injuries, result from traumatic shearing forces with separation of the subcutaneous fat from the underlying fascia. The aim of this study was to determine the incidence and treatment of MLLs at a level 1 trauma centre. METHODS: Single-centre retrospective cross-sectional study of consecutive patients with an imaging diagnosis of a Morel-Lavallee lesion from 1/1/2010-31/12/2019. Demographic data, mechanism of injury, volume of lesion, management and outcome data were collated. RESULTS: Sixty-six MLLs were identified in 63 patients (64% Male) with a median age of 49.5 years (19-94 years). Mechanism of injury were road traffic accidents in the majority (66%). Median injury severity score (ISS) was 17 (range 1-33). Patients on oral anti-coagulants had significantly larger lesions (181.9 cc v 445.5 cc, P = 0.044). The most common lesion location was the thigh (60.5%). Patients that underwent imaging within 72 h of injury had significantly larger lesions than those imaged more than 72 h after the inciting trauma (65 cc v 167 cc, P < 0.05). Management data were documented in 59% of lesions (39/66) in which 66.6% (n = 26) had invasive treatment. In the 31 patients where follow-up was available, 64.5% (n = 20) were persistent but decreasing in size. There was no significant difference in follow-up size for those who had invasive compared to conservative treatment (P = 0.3). CONCLUSION: The diagnosis of MLL should be considered for soft-tissue swelling in the context of shearing trauma. A variety of management options have been employed, with good overall outcomes.

Application of the predicted biomechanics approach in assessing work-related musculoskeletal discomfort among female brickfield workers in West Bengal, India.

BACKGROUND: Manual brick manufacturing units in West Bengal, India are mostly unorganized sectors employing many migrant female workers in manual material handling tasks as brick moulders and brick carriers. OBJECTIVE: The study estimated the biomechanical postural stress developed due to manual load handling, carriage and brick transportation. METHODS: Body Part Discomfort Scale was used to assess the subjective pain felt by 18 adult female brick moulders and 12 brick carriers during work. Video recordings were taken during the actual field work and the images were analyzed for two-dimensional prediction kinetics and kinematics. RESULTS: Results show that the horizontal distance of the load from the body was 59.95±3.74 cm during the initial lifting of bricks by the brick carriers and so their biomechanical trunk angle inclination was significantly detrimental. The bending moment at the lumbosacral disc was much higher during the squatting posture while initial brick lifting. Moreover, the trunk and the neck pain of the brick carriers were caused by carrying 18% of body weight load. CONCLUSIONS: The brick carriers were the more vulnerable group in terms of work-related musculoskeletal disorders. Therefore, ergonomic interventions such as relay brick carrying and pole supported balanced brick carrying, may be implemented to reduce the prevalence of pain. This study is the first of its kind that validates the extent or the prevalence of work-related musculoskeletal disorders among the female brickfield workers through approaches of predicted biomechanics.

Highly Sensitive Flexible Tactile Sensor Mimicking the Microstructure Perception Behavior of Human Skin.

A 3D printed flexible tactile sensor with graphene-polydimethylsiloxane (PDMS) microspheres for microstructure perception is presented. The structure of the tactile sensor is inspired by the texture of the human finger and is designed to enable the detection of various levels of surface roughness via the processing of tactile signals. The tactile sensor with a unique graphene-PDMS microsphere structure shows excellent comprehensive mechanical properties, including a robust stretching ability (elongation at break of the sensing layer is 70%), excellent sensing ability (short response time of 60 ms), high sensitivity (sensitivity up to 2.4 kPa-1), and cycle stability (over 2000 loading cycles). In addition, such versatility and sensitivity allow the electronic skin not only to accurately monitor pressure but also to distinguish various surface topographies with microscale differences, and to detect the action of an air fluid.

Glenohumeral contact force during flat and topspin tennis forehand drives.

The primary role of the shoulder joint in tennis forehand drive is at the expense of the loadings undergone by this joint. Nevertheless, few studies investigated glenohumeral (GH) contact forces during forehand drives. The aim of this study was to investigate GH compressive and shearing forces during the flat and topspin forehand drives in advanced tennis players. 3D kinematics of flat and topspin forehand drives of 11 advanced tennis players were recorded. The Delft Shoulder and Elbow musculoskeletal model was implemented to assess the magnitude and orientation of GH contact forces during the forehand drives. The results showed no differences in magnitude and orientation of GH contact forces between the flat and topspin forehand drives. The estimated maximal GH contact force during the forward swing phase was 3573 ± 1383 N, which was on average 1.25 times greater than during the follow-through phase, and 5.8 times greater than during the backswing phase. Regardless the phase of the forehand drive, GH contact forces pointed towards the anterior-superior part of the glenoid therefore standing for shearing forces. Knowledge of GH contact forces during real sport tasks performed at high velocity may improve the understanding of various sport-specific adaptations and causative factors for shoulder problems.

Selective effects of head posture on ocular vestibular-evoked myogenic potential (oVEMP) by bone-conducted vibration.

OBJECTIVE: By altering head postures from sitting, supine to head hanging, this study investigated the effects of gravitational force on ocular vestibular-evoked myogenic potential (oVEMP) via either air-conducted sound (ACS) or bone-conducted vibration (BCV) stimuli. METHODS: Twenty healthy volunteers underwent the oVEMP test via ACS or BCV stimuli with the sitting, supine, and head hanging positions on the same day in a randomized order. RESULTS: All subjects had clear BCV oVEMPs in the three head postures. No significant differences existed in terms of mean nI and pI latencies, the nI-pI interval, and asymmetry ratio regardless of various positions. However, the mean nI-pI amplitude with the head hanging position (15.9 ± 6.4 µV) was significantly larger than that with the sitting position (13.8 ± 6.0 µV), but not significantly larger than that with the supine position (14.7 ± 6.1 µV). Nevertheless, such a difference in reflex amplitude does not exist in oVEMPs elicited by ACS stimuli. With the sitting position, mean linear acceleration at the mastoids in response to BCV stimuli was -0.06 ± 0.02, 0.20 ± 0.04 and -0.04 ± 0.02 g along the x-, y-, and z-axis, respectively, which did not differ significantly from those with the head hanging position. CONCLUSION: By altering head postures from sitting to head hanging, gravitational force can exert a selective effect on the reflex amplitude of oVEMPs elicited by BCV stimuli, but not by ACS stimuli. SIGNIFICANCE: Compared to ACS mode, BCV mode can provoke higher response rate, generate earlier and larger waveforms, and be influenced by both dynamic shearing force and static gravitational force to enlarge the reflex amplitude of oVEMPs.

Fatal thrombocytopenia: A rare case with possible explanation.

A 22 year old male presented with breathlessness on exertion, ecchymosis, jaundice and features of worsening right heart failure for the last fifteen days. On physical examination, he had a mid diastolic murmur in the tricuspid area and an ejection systolic murmur in the pulmonary area. Bone marrow histopathology report showed an increased in megakaryocytes count. Routine investigations reports were normal. Echocardiography and computerized tomography (CT) revealed a single mobile large intra cardiac mass originating from the right atrium and causing dynamic obstruction of the right ventricular inflow and outflow tract. Associated fatal thrombocytopenia did not respond to intravenous steroids or platelet transfusion. Patient could not be operated because of very low platelet count, and died during hospital stay before excision biopsy could be done. Pathological autopsy was not done. This is a rare case, as the fatal thrombocytopenia observed here was the result of mechanical effects like frictional and shear force, which can be attributed to the physical presence of a large intra cardiac mass resulting in obstruction to flow.