Repetitive Friction Research Articles

Molecular dynamics study on the nanofriction and wear mechanism of transverse grain boundaries in nickel-based alloys.

This study employs molecular dynamics simulations to investigate the nanoscale tribological behavior of a single transverse grain boundary in a nickel-based polycrystalline alloy. A series of simulations were conducted using a repetitive rotational friction method to explore the mechanisms by which different grain boundary positions influence variations in wear depth, friction force, friction coefficient, dislocation, stress, and internal damage during repeated friction processes. The results reveal that the grain boundary structure enhances the strength of the nanoscale nickel-based polycrystalline alloy. When the friction surface is far from the transverse grain boundary, the grain boundary's obstructive effect is weaker, leading to larger ranges of atomic displacement and migration of internal defects. This results in smaller fluctuations in friction force and coefficient, along with the formation of numerous densely packed downward defect bundles. At the grain boundary, two grains undergo relative slip along the grain boundary interface, while atoms below the grain boundary remain largely unaffected. When the grain boundary is closer to the friction surface, more wear debris atoms accumulate in front of and on the sides of the friction grinding ball, increasing the friction force during the process. If the friction grinding ball breaches the grain boundary layer, its supporting and strengthening effects are diminished, leading to a significantly greater wear depth compared to when the grain boundary remains intact. In this paper, nanoscale modeling was performed in the large-scale atomic/molecular parallel simulator simulation environment (LAMMPS). Three potential functions, namely EAM potential, Morse potential, and Tersoff potential, are used to simulate the interaction between atoms during the processing. The model was visualized and analyzed in three dimensions by Open Visualization Tool (OVITO).

Natural Approaches & Transdermal Innovations for Foot Corns: A Comprehensive Review

Skin diseases are among the most prevalent health concerns worldwide, affecting billions. Foot corns, also known as clavus, are a significant issue within this category. These thickened skin lesions, marked by a cone-shaped keratin core, arise from repetitive friction or pressure, often due to poor-quality or ill-fitting footwear. Women are disproportionately affected, largely because of specific footwear choices. Corns and calluses, although similar, have distinct features and locations, both causing discomfort and leading many to seek podiatric care. Foot corns affect 14% to 48% of the population, underscoring the need for effective treatments. Transdermal drug delivery systems have emerged as a promising solution, offering controlled, targeted medication delivery through self-contained patches, which minimizes systemic side effects. Recent research indicates the potential of combining natural remedies such as turmeric, neem, aloe vera, and tea tree oil with Transdermal drug delivery system for treating foot corns. These natural ingredients, known for their therapeutic properties, enhance treatment outcomes when used with advanced drug delivery technology. This combination not only increases the effectiveness of managing foot corn but also improves the quality of life for affected individuals. The success of the Transdermal drug delivery system in treating foot corns highlights the need for further research to optimize these systems and ensure their accessibility. For individuals with chronic foot issues, where traditional treatments may be inadequate, Transdermal drug delivery combined with natural remedies represents a significant advancement. This innovative approach offers a more effective and practical solution for managing foot corns and other skin conditions, providing hope and relief to millions worldwide.

Management of Corn Using Agnikarma

Corns (clavi) are a common painful condition caused by hyperkeratosis due to repetitive friction or pressure. Agnikarma, an Ayurvedic thermal cauterization technique, is traditionally used to treat various musculoskeletal and dermatological conditions. This case study evaluates the efficacy of Agnikarma in treating a corn on the sole of a patient's foot. Patient Profile: A 45-year-old male school teacher presented with a painful corn on the plantar aspect of her right foot. The corn had been persistent for six months, causing severe discomfort while walking or standing. The patient opted for Agnikarma after conventional treatments were discussed. Method: The corn was marked and the surrounding area cleaned. A heated Shalaka (metal rod) was applied to the corn in a circular motion to achieve a therapeutic burn. Post-procedure care included keeping the area clean and dry with regular dressing changes. Results: The patient experienced significant pain relief one week post-procedure, with the corn reducing in size by four weeks. By eight weeks, the corn had completely resolved with no recurrence or complications. The patient reported no discomfort and was able to resume normal activities. Conclusion: Agnikarma provided effective and immediate relief for the patient’s corn, showcasing its potential as a minimally invasive and cost-effective treatment. This technique promotes localized tissue necrosis and healing, making it a valuable alternative to conventional treatments, particularly for patients seeking prompt pain relief and reduced recurrence.

The Effect of Neurophysiological Modulation on Muscle Power and Pain Through Manual Therapy Over Electro- Physiotherapy for Athletes with Illio Tibial Band Syndrome (ITBS)

Introduction and Objectives: Iliotibial Band Syndrome (ITBS) is a common overuse injury in athletes, primarily impacting the knee and hip due to repetitive friction of the iliotibial band against the femur, resulting in pain and restricted hip abduction and knee extension. Muscle power and pain associated with ITBS can be measured using Hand-held Dynamometer (HHD) and Visual-Analog-Scale scores (VAS) respectively. This study aimed to compare the efficacy of two treatment groups, Manual-Therapy (MT) and Electro-Physiotherapy (EPT), in determining the most effective approach for managing ITBS. Materials and Methods: A RCT was conducted at the Sports Medicine Clinic of the Teaching Hospital Karapitiya, enrolling twenty athletes in each group as controls and experimental subjects. The control group received EPT, NSAIDS, and paracetamol for one week, while the experimental group received MT, NSAIDS, and paracetamol for the same duration. Muscle power and pain measurements were assessed using HHD & VAS on D1 and D28. P-values for statistical significance were obtained using RM-ANOVA followed by Bonferroni test. Results: Mean ages for EPT and MT groups were 24.4±6.6 and 25.4±6.6years, respectively. Muscle power (N) for EPT group on D1, and D28 were 101.7±26.3 and 112.7±23 respectively. The same parameters for MT group were 98.1±26 and 186.8±25.3. The mean differences for muscle power of two groups on D1 and D28 were -3.600(P=0.666) and 74.050(P<0.001). VAS scores for EPT group on D1, and D28 were 8.2±0.9 and 7±1 respectively. The same parameters for MT group were 7.9±0.8 and1.8±0.8. The mean differences for pain of two groups on D1 and D28 were 0.250(P=0.395) and -5.200(P<0.001). Partial-Eta-Squared for the two groups were 0.355 and 0.758respectively. ManualTherapy group’s higher effectiveness was statistically significant (p<0.001) and a 35.5% variance in muscle power and 75.8% variance in VAS score was attributable to it. Conclusion:Manual-therapy is superior to electro-physiotherapy in improving muscle power and decreasing in VAS scores of athletes with ITBS.

Atomic-scale study of linear reciprocating friction of TCP/γ phase in nickel-based single crystal alloy

In order to systematically investigate the role of TCP (topologically close-packed) phases in the fretting wear process of nickel-based single crystal alloys (NBSC), this study employed molecular dynamics to conduct comparative analyses of mechanical properties, atomic displacements, wear depth, defects, dislocation density, and the influence of temperature under constant load on the friction process in material wear. The research revealed that during the repetitive friction process, the friction force exhibited a peak at the extreme positions of reciprocating friction on the workpieces, and this peak increased with the number of friction cycles. The dislocation density in the worn area increased, resulting in hardening, and the removal rate of material decreased. At the initial stages of friction, the presence of interfaces notably hindered the transfer of temperature, defects, and atomic displacements in the workpiece, and this inhibitory effect weakened with an increasing number of friction cycles. The TCP phases experienced stratification due to the overall deformation they underwent. Furthermore, as the relaxation temperature increased, the workpiece exhibited enhanced plastic deformation capacity, an increase in dislocation density, and adhesion between abrasive particles and the grinding ball occurred.

Molecular dynamics study of the repetitive friction mechanism of nickel-based single crystals in an aqueous environment

In this study, molecular dynamics simulations were used to simulate the iterative rotational friction of nickel-based single crystals using diamond grinding balls in both the presence and absence of water. First, the friction force, depth and morphology of wear marks, wear rate, and evolution of internal defects during the friction process of nickel-based single crystals were investigated. Second, a comparative study of the frictional wear of nickel-based single crystals in both the presence and absence of water was carried out in terms of temperature, water molecule distribution, atomic displacement vector, and wear scar depth during the friction process. Finally, the formation process of irregular grinding chips under aqueous conditions was elucidated. The following phenomena were observed: As the number of rubs increased, the single rub depth of the workpiece, the wear rate, and the rate of increase in the number of defective atoms produced all decreased. A comparison of friction under aqueous and water-free conditions showed that, in the presence of water, the force exerted by the grinding ball on the workpiece was shared by the water molecules. This resulted in a decrease in the roughness of the machined surface, a reduction in the number of internally generated layer errors, a lower overall friction temperature, and a nickel matrix that was protected by water molecules. Finally, when grinding under aqueous conditions, water molecules interfered with the normal chip removal process of the grinding balls, leading to the production of irregular grinding chips.

Correlation between Leg Length Discrepancies (LLD) with ITB Syndrome: A Systematic Review

Backgrounds: Iliotibial band syndrome (ITBS) is one of the many different causes of lateral knee pain. The iliotibial band (ITB) is the distal fascial continuation of the tensor fascia lata, gluteus medius, and gluteal maximus. It traverses superficial to the vastus lateralis and inserts on the Gerdy tubercle of the lateral tibial plateau and partially to the supracondylar ridge of the lateral femur. The etiology of ITBS is controversial and likely multifactorial. One theory advocates that repetitive friction of the ITB and the lateral epicondyle during flexion and extension lead to inflammation of the contact area of the ITB. The discrepancy in leg length has long been a source of controversy in the research and clinical environment. It disagrees on many aspects, such as its effect on various neuro musculoskeletal disorders and the evaluation of different measurement methods. Several orthopaedic disorders have also been associated with LLD, including low back pain, iliotibial band syndrome, hip osteoarthritis, intervertebral disc disease, and stress fractures of the femur, tibia, fibula, and metatarsal bones. Methods: Our trial was an international, expertise-based, randomized, controlled trial. Details of the trial objectives and design have been published previously. To identify studies about correlation between leg length discrepancy with ITB Syndrome, we reviewed the Cochrane, Pubmed, Embase databases for relevant articles published up to June 2022. Following the PICOS (Participants, Interventions, Comparisons, Outcomes and Study design) principle, the key search terms included (P) patients with ITB syndrome; (I) Leg length discrepancy; (C/O) the comparisons between ITB syndrome with leg length discrepancy thant without leg length discrepancy; (S) RCT, cohort study, or case-control study. Results: This study results Literature search through The flow diagram of study selection that shown in Figure 1. A total of RCT, cohort and case control study, meta analysis and systematic review about correlation between leg length dicrepancy with ITB Syndrome.Discussions: There can be a predisposition to developing IT band syndrome. Anatomy issues may include leg length discrepancy, an abnormal tilt to the pelvis, or bowed legs (genu varum). These situations can cause the IT band to become excessively tight, leading to increased friction and irritation as the band crosses over the femoral condyle with movement. leg length discrepancy, which can also increase ITB tightness. Leg length discrepancy can make an impact to biomechanical abnormalities. ITBS is usually caused by biomechanical abnormalities, often combined with overtraining. Conclusions: This confirms that may be leg length discrepancy also a factor that contributes to iliotibial band syndrome (ITBS).

Iliotibial Band Friction Syndrome: A Common Cause of Lateral Knee Pain in Long-Distance Runners

Introduction: Iliotibial band friction syndrome (ITBFS) is an injury of the knee joint which is common in long distance runners and cyclists. It is caused by repetitive friction between the iliotibial band and the lateral femoral epicondyle during active flexion and extension of the knee. Methods: Magnetic resonance imaging of the knee was performed for 45 long distance runners who presented with lateral knee pain after long distance running for 6 months. The analysis of the images was done by two radiologists in all the three planes to confirm or rule out any findings suggestive of ITBFS. The various imaging features which were noted in the MRI scans by the radiologists to label it as ITBFS were poorly defined abnormal signal intensity deep to the iliotibial band as the primary finding and other associated MRI findings such as fluid collection medial to the iliotibial band, increased thickness of the iliotibial band and joint effusion. Results: Out of these 45 runners 30 patients had ITBFS, 3 had lateral collateral ligament sprain, 3 had a grade III tear of the lateral meniscus, 3 had synovial effusion and six had normal scans. Discussion: Iliotibial band friction syndrome occurs because of overuse and can be confused with other disorders and MRI is able to differentiate it from other conditions.

Failure of refractory masonry material under monotonic and cyclic loading – Crack propagation analysis

Refractory masonry (refractories) is exposed to in-service loads of different types. To rationalise the masonry design and failure analysis, differences of failure under cyclic and monotonic loading were studied. For samples of silica refractories tested in wedge splitting set-up global failure parameters and crack trajectories were assessed. Under cyclic loading, higher fracture energy and lower brittleness at failure were seen. Cracks of different modes had similar non-linearity and branching. However, the size and microstructural characteristics of the fracture process zone was different. In addition, higher energy dissipation during cyclic loading is promoted by repetitive friction events along the crack trajectory.

Nondestructive Quantitative Evaluation of Yarns and Fabrics and Determination of Contact Area of Fabrics Using the X-ray Microcomputed Tomography System for Skin-Textile Friction Analysis.

In different mechanical conditions, repetitive friction in combination with pressure, shear, temperature, and moisture leads to skin discomfort and imposes the risks of developing skin injuries such as blisters and pressure ulcers, frequently reported in athletes, military personnel, and in people with compromised skin conditions and/or immobility. Textiles next to skin govern the skin microclimate, have the potential to influence the mechanical contact with skin, and contribute to skin comfort and health. The adhesion-friction theory suggests that contact area is a critical factor to influence adhesion, and therefore, friction force. Friction being a surface phenomenon, most of the studies concentrated on the surface profile or topographic analysis of textiles. This study investigated both the surface profiles and the inner construction of the fabrics through X-ray microcomputed tomographic three-dimensional image analysis. A novel nondestructive method to evaluate yarn and fabric structural details quantitatively and calculate contact area (in fiber area %) experimentally has been reported in this paper. Plain and satin-woven fabrics with different thread densities and made from 100% cotton ring-spun yarns with two different linear densities (40 and 60 Ne) were investigated in this study. The measurements from the tomographic images (pixel size: 1.13 μm) and the fiber area % analysis were in good agreement to comprehend and compare the yarn and fabric properties reported. The fiber area % as reported in this paper can be used to evaluate the skin-textile interfaces and quantitatively determine the contact area under different physical, mechanical, and microclimatic conditions to understand the actual skin-textile interaction during any physical activity or sports. The proposed method can be helpful in engineering textiles to enhance skin comfort and prevent injuries, such as blisters and pressure ulcers, in diversified application areas, including but not limited to, sports and healthcare apparel, military apparel, and firefighter's protective clothing. In addition, the images were capable of precisely evaluating yarn diameters, crimp %, and packing factor as well as fabric thickness, volumetric densities, and cover factors as compared with those obtained from theoretical evaluation and existing classical test methods. All these findings suggest that the proposed new method can reliably be used to quantify the yarn and fabric characteristics, compare their functionality, and understand the structural impacts in an objective and nondestructive way.

Skin in the game: Video-game-related cutaneous pathologies in adolescents.

BackgroundFollowing the inception of video games and the subsequent development of progressive innovations in videogame technology, many reports of videogame-related dermatologic conditions soon emerged in literature. Children and adolescents, in particular, are among the most avid consumers of online digital entertainment.MethodsIn an effort to better detail the impacts of these cutaneous manifestations and provide recommendations for injury prevention as it relates to video games, we performed an extensive systems-based literature review pertaining to the clinical features, etiology, diagnosis, and treatment of reported cases of dermatoses resulting from the misuse of video games.ResultsA literature review using PubMed, SCOPUS, Ovid MEDLINE and EMBASE was performed. Hardware implicated in the reported cases include video games consoles, personal computers, laptop computers, mobile phones and tablets. The dermatologic conditions are primarily localized to the extremities, particularly the palms and fingers. The majority are associated with repetitive friction and trauma, as well as allergic contact sensitivities. For all cutaneous manifestations induced by video gaming, early recognition and removal of the offending agent was most often described as effective in symptom resolution.ConclusionsThe universal use and pervasive popularity of video games for recreational purposes present an emerging dermatological concern. As videogames become increasingly advanced and immersive, various cutaneous conditions arising from intensive gaming will likely become common over time. Consequently, it is critical that dermatologists consider video games with a high index of suspicion when encountering dermatological ailments in underage patients engaging in persistent gaming behavior.

Interparticle Bonding of Cu Powder under Repetitive Unidirectional Friction

Interparticle Bonding of Cu Powder under Repetitive Unidirectional Friction

Dysphagia Caused by Cervical Plate Erosion through the Hypopharynx

CASE REPORT A 53-year-old woman with a history of neurofibromatosis, Hodgkin's lymphoma, and C3-T2 fusion 4 years prior for swan-neck cervical deformity was admitted for evaluation of left frontal skull mass and progressively worsening dysphagia of solid foods and thick liquids over 6 weeks. Computed tomography (CT) of the abdomen, pelvis, and lumbothoracic spine showed multiple hypodense liver lesions and diffuse sclerotic bone lesions within the thoracic and lumbar spine, ribs, sacrum, and ischium suspicious for metastatic malignancy. Fine-needle aspiration of the liver lesions yielded immunochemistry positive for focal CA 19-9 staining suggestive of adenocarcinoma of upper gastrointestinal (GI) origin. Serum CEA and CA 19-9 were within normal limits. Esophagogastroduodenoscopy did not reveal an upper GI tumor; however, a metal object was seen in the hypopharynx just above the upper esophageal sphincter (Figure 1). It appeared to be fixed and could not be moved with grasping forceps. The adult gastroscope could not be advanced beyond the object; however, the ultraslim could. A sagittal CT view of the neck with contrast showed the offset of the anterior cervical internal fusion plate with direct communication to the hypopharyngeal airway and suggesting erosion through the posterior hypopharyngeal soft tissue (Figure 2). Given the patient's multiple comorbidities and presumably metastatic cholangiocarcinoma, neurosurgery service recommended medical management rather than surgical management. A 6-week course of intravenous ertapenem was initiated due to the high risk of abscess formation. The patient underwent gastric tube placement for feeding and was eventually discharged under hospice care.Figure 1.: Esophagogastroduodenoscopy showing a foreign metal object in the hypopharynx above the upper esophageal sphincter.Figure 2.: Sagittal view of the neck with contrast-enhanced computed tomography showing direct communication between the anterior cervical internal fusion plate and the hypopharyngeal airway.Dysphagia is an underrecognized but significant complication of cervical fusion surgeries.1 The incidence of esophageal perforation after anterior cervical spine surgery is estimated to be between 0.02% and 1.49% with a mortality rate of 6%.2 Most esophageal erosions occur in the intraoperative or immediate postoperative setting, although there has been an increase in cases with delayed presentation, which often lead to dramatic clinical deterioration with a higher mortality risk of 20-50%.3 Most esophageal injuries are due to iatrogenic injury intraoperatively from inappropriate placement or dislodgement of retractors or hardware migration. Delayed injuries are typically due to chronic compression, abscess formation, repetitive friction of the plating system, or hardware dislodgement and chronic migration.4 Diagnosis can be made with cervical radiographs; however negative imaging does not rule out esophageal injury. Operative intervention is recommended, but conservative medical treatment is appropriate depending on the patient and the clinical circumstances.5 Although cervical endplate erosion of the esophagus has been well documented in the literature, hypopharyngeal erosion has only been reported once previously.6 It is imperative that health care providers are vigilant and complete a thorough workup in patients with persistent or worsening dysphagia who have undergone a previous anterior cervical surgery. DISCLOSURES Author contributions: S. Kothari and T. Almouradi wrote the manuscript. T. Almouradi is the article guarantor.

Dysphagia Caused by Cervical Plate Erosion through the Hypopharynx

CASE REPORT A 53-year-old woman with a history of neurofibromatosis, Hodgkin's lymphoma, and C3-T2 fusion 4 years prior for swan-neck cervical deformity was admitted for evaluation of left frontal skull mass and progressively worsening dysphagia of solid foods and thick liquids over 6 weeks. Computed tomography (CT) of the abdomen, pelvis, and lumbothoracic spine showed multiple hypodense liver lesions and diffuse sclerotic bone lesions within the thoracic and lumbar spine, ribs, sacrum, and ischium suspicious for metastatic malignancy. Fine-needle aspiration of the liver lesions yielded immunochemistry positive for focal CA 19-9 staining suggestive of adenocarcinoma of upper gastrointestinal (GI) origin. Serum CEA and CA 19-9 were within normal limits. Esophagogastroduodenoscopy did not reveal an upper GI tumor; however, a metal object was seen in the hypopharynx just above the upper esophageal sphincter (Figure 1). It appeared to be fixed and could not be moved with grasping forceps. The adult gastroscope could not be advanced beyond the object; however, the ultraslim could. A sagittal CT view of the neck with contrast showed the offset of the anterior cervical internal fusion plate with direct communication to the hypopharyngeal airway and suggesting erosion through the posterior hypopharyngeal soft tissue (Figure 2). Given the patient's multiple comorbidities and presumably metastatic cholangiocarcinoma, neurosurgery service recommended medical management rather than surgical management. A 6-week course of intravenous ertapenem was initiated due to the high risk of abscess formation. The patient underwent gastric tube placement for feeding and was eventually discharged under hospice care.Figure 1.: Esophagogastroduodenoscopy showing a foreign metal object in the hypopharynx above the upper esophageal sphincter.Figure 2.: Sagittal view of the neck with contrast-enhanced computed tomography showing direct communication between the anterior cervical internal fusion plate and the hypopharyngeal airway.Dysphagia is an underrecognized but significant complication of cervical fusion surgeries.1 The incidence of esophageal perforation after anterior cervical spine surgery is estimated to be between 0.02% and 1.49% with a mortality rate of 6%.2 Most esophageal erosions occur in the intraoperative or immediate postoperative setting, although there has been an increase in cases with delayed presentation, which often lead to dramatic clinical deterioration with a higher mortality risk of 20-50%.3 Most esophageal injuries are due to iatrogenic injury intraoperatively from inappropriate placement or dislodgement of retractors or hardware migration. Delayed injuries are typically due to chronic compression, abscess formation, repetitive friction of the plating system, or hardware dislodgement and chronic migration.4 Diagnosis can be made with cervical radiographs; however negative imaging does not rule out esophageal injury. Operative intervention is recommended, but conservative medical treatment is appropriate depending on the patient and the clinical circumstances.5 Although cervical endplate erosion of the esophagus has been well documented in the literature, hypopharyngeal erosion has only been reported once previously.6 It is imperative that health care providers are vigilant and complete a thorough workup in patients with persistent or worsening dysphagia who have undergone a previous anterior cervical surgery. DISCLOSURES Author contributions: S. Kothari and T. Almouradi wrote the manuscript. T. Almouradi is the article guarantor.

Imaging Features of Symptomatic Hypertrophic Tuberculum Peroneum.

Objective:The aim of this article is to review the clinical and imaging features of symptomatic hypertrophic (TP) in a cohort of symptomatic patients.Materials and Methods:Twenty-three patients with chronic lateral ankle pain were retrospectively included in our study group. Patients underwent ultrasound (US), (cone beam) computed tomography (CB)CT or magnetic resonance (MR) examination or a combination of these examinations with a standardized protocol. Patients with an underlying fracture were excluded. The following parameters were recorded: clinical history, size of the TP on different imaging modalities, presence and grade of peroneus brevis/longus tenosynovitis and the presence of bone marrow edema at the os calcaneus on magnetic resonance imaging (MRI).Results:The mean width of the hypertrophic TP was 5.6 mm. Combined tenosynovitis of the peroneus longus (PL) and brevis tendon (PB) was most common, followed by isolated PL and finally PB tenosynovitis. Grade 1 tenosynovitis was most common. BME was present in 53% of the cases.Conclusion:The width of the TP is may be evaluated on the (oblique) coronal US, (CB)CT or non-fat suppressed MR images. Both US and MRI may detect and grade involvement of the peroneal tendons. By the use of fluid sensitive sequences, MRI may be of additional value to detect bone marrow edema as result of repetitive friction.

Corns in scleroderma: An underreported entity.

Sir, Systemic sclerosis (SSc) has been associated with a myriad of foot problems ranging from Raynaud's phenomenon to degenerative changes.[1] However, the occurrence of plantar corns in patients with SSc, as noticed consistently by one of the authors, has remained an unreported entity to the best of our knowledge. Based on this observation, we set out to assess the frequency of corns in scleroderma and the possible pathomechanism behind it. For this purpose, during a one-year period (March 2011 to February 2012) we studied 18 patients with SSc and 5 patients with mixed connective tissue disease who were diagnosed based on the criteria developed by the American College of Rheumatology and Kasukawa et al., respectively.[23] On examination, all the 18 patients with scleroderma and 3 of 5 MCTD patients were found to have corns on the plantar aspect of their feet. All the lesions had a sharp, discrete border with interrupted dermatoglyphics, thus distinguishing them from callosities [Figure 1]. Also, the lesions did not show any bleeding points following paring, thus negating the possibility of plantar warts. All the patients complained of tenderness, which increased on applying vertical pressure.Figure 1: Lesion showing central shiny nucleus and absence of dermatoglyphicsThe total number of lesions encountered by us summed up to 60; 20 on the heel area, 24 present lateral to the head of 1st metatarsal, and 15 present between the heads of 4th and 5th metatarsal [Figure 2]. Fifteen patients showed involvement of bilateral feet albeit not necessarily symmetrical. Incidentally, all the 18 patients of SSc had digital pitted scars [Figure 3].Figure 2: Schematic representation of the distribution of cornsFigure 3: (a and b) Corns with digital pitted scarring. (c) Corns seen on the heels. Right forefoot amputated secondary to ischemic ulcersCorn develops because of an interplay between increase in the pressure on bony prominences and accumulation of the horny layer of the epithelium, thus generating a vicious cycle, which ultimately culminates in the formation of a keratin plug pressing into the dermis.[4] People with SSc also suffer from bone erosions and subcutaneous fat atrophy, consequently increasing plantar foot pressure. Adding to this melee is the prevalent tradition of walking barefoot indoors in this part of the subcontinent, which can increase the wear and tear effect. Furthermore, studies on plantar pressure in scleroderma have demonstrated a particularly high peak pressure in the MTP joint, which substantiates our finding of increased occurrence of corns in the forefoot area.[5] In this study, the all-female population were housewives and had to perform most of their chores standing. This can lead to a further increase in the peak pressure in the MTP joints. The presence of corns can be considered as a marker for ulceration as the mechanical forces that cause corns and Calluses can also rupture portions of subcutaneous vascular plexus. In healthy patients this may be of minimal significance, but in patients with connective tissue disease it may herald extensive skin ulceration or vasculitis.[5] Thus, corns can be regarded as a sign of the onslaught brought about by the repetitive friction and shear. When the enormity of systemic involvement in SSc is considered, the association of corn may seem trivial. However, knowledge about its occurrence and prompt redressing will go a long way in alleviating the burden of pain and in avoiding more sinister complications such as ulceration. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

Mechanism of interparticle bonding of metal powder by repetitive unidirectional friction process

Mechanism of interparticle bonding of metal powder by repetitive unidirectional friction process

Pachydermodaktylie

Pachydermodactyly is an acquired swelling of the lateral aspects of the fingers and is thought to be areactive pattern due to exogenous factors, such as repetitive mechanical friction. We describe the clinical case of a 17-year-old male patient who presented with the typical symptoms of pachydermodactyly.

Effects of kinesiotaping versus non-steroidal anti-inflammatory drugs and physical therapy for treatment of pes anserinus tendino-bursitis: A randomized comparative clinical trial

ABSTRACTObjective: Pes anserinus tendino-bursitis is a condition caused by repetitive friction over the bursa or direct trauma to knee joint and it presents with proximal medial tibial pain and swelling. The aim of this study is to determine the effects of kinesiotaping in comparison with naproxen and physical therapy in treatment of pes anserinus tendino-bursitis.Methods: In a randomized comparative clinical trial 56 patients with clinical diagnosis of pes anserinus tendino-bursitis were randomly assigned to kinesiotaping and naproxen/physical therapy (28 patients in each group). Kinesiotaping on the tender area in the form of space-correction (lifting) technique was used and repeated for three times with a one-week interval. Another group received naproxen (250mg TID for 10 days) and ten sessions of daily physical therapy. The visual analog scale (VAS) was used for evaluation of pain. The depth of swelling of the area was measured with sonography before and after treatment. Wilcoxon signed ranks test has been used for determining the influence of interventions on pain (VAS) and swelling scores in each group. The ANCOVA (Analysis of covariance) test was applied for comparing the influence of interventions on VAS and swelling scores after adjustment for co-variables.Results: At end of the study, 27 patients remained in the kinesiotaping group and 19 patients in naproxen/physical therapy group. Treatment with kinesiotaping significantly decreased the pain (P=0.0001) and swelling scores (P=0.0001) in comparison with naproxen/physical therapy after adjustment for baseline characteristics. Kinesiotaping was safe without any complications except for a mild local skin irritation in one patient.Conclusion: Kinesiotaping is more effective than naproxen plus physical therapy in reduction of pain and swelling in patients with pes anserinus tendino-bursitis.Clinical trial registration: www.ClinicalTrials.gov identifier is NCT01680263

Pediatric Positional Sitting Dermatitis: A New Form of Pediatric Contact Dermatitis.

We report on four pediatric patients who presented with localized dermatitis in areas subject to repetitive friction due to their sitting positions. We propose that the cause of the eruption was irritant contact dermatitis due to frequently sitting in a crossed-leg sitting position, an entity for which we have coined the term pediatric positional sitting dermatitis (PPSD). The goal of this report is to raise clinicians' awareness of PPSD, which to our knowledge has not been previously described, and to discuss management of these patients.