The material properties of articular cartilage are depth-dependent, i.e. they differ in the superficial, middle and deep zones. The role of this depth-dependent material inhomogeneity in the poromechanical response of the knee joint has not been investigated with patient-specific joint modeling. In the present study, the depth-dependent and site-specific material ...

Extra-articular extravasation of irrigation fluid is relatively common around entry incisions and is usually limited to the subcutaneous tissue. Very rarely, extravasation occurs above the knee, in the thigh and even up into the pelvis. We are reporting the second case of irrigation fluid extravasation during a knee arthroscopy, which ...

Medial patellofemoral ligament (MPFL) disruption may alter patellofemoral joint (PFJ) kinematics and contact mechanics, potentially causing pain and joint degeneration. In this controlled laboratory study, we investigated the hypothesis that MPFL transection would change patellar tracking and PFJ contact pressures and increase the distance between the attachment points of the ...

BACKGROUND: The goat is one of the most commonly used preclinical models for focal defect repair and regeneration. While the biomechanics of the human knee has been studied extensively, less is known about the biomechanics of the caprine knee. Differences between human and caprine knees have not been quantified and ...

PURPOSE: The purpose of this study was to evaluate the effects of different types of lateral meniscus root tears in terms of tibiofemoral contact stress. METHODS: Ten porcine knees each underwent five different testing conditions with the menisci intact, a simulated lateral posterior root tear with and without cutting the ...

BACKGROUND: Osteochondral autograft transfer (OAT) aims at restoring normal articular cartilage surface geometry and articular contact mechanics. To date, no studies have evaluated the contact mechanics of the canine stifle following OAT. Additionally, there are no studies that evaluated the role of the meniscus in contact mechanics following OAT in ...

PURPOSE: The purpose of this study was to test the hypothesis that the surgical technique using alternating fluid irrigation and carbon dioxide (CO2) gas medium as a means of knee joint distension during arthroscopy is a safe and effective method, compared to traditional fluid arthroscopy. METHODS: This prospective randomized comparative ...

This article presents a pilot study on a quasi-static knee rig designed to investigate the influence of pathologies and surgical interventions on the patellofemoral kinetics of cadaveric knees. The knee rig allows cadaveric knees to flex and extend under a simulated body weight by transmitting a force to the quadriceps ...

PURPOSE: Considering the discrepant results of the recent biomechanical studies, the purpose of this study was to simulate dynamic muscle-loaded knee flexion with a large number of specimens and to analyse the influence of total knee arthroplasty (TKA) without and with patellar resurfacing on the patellofemoral pressure distribution. METHODS: In ...

BACKGROUND: The rabbit knee is a frequently used model for experimental osteoarthritis (OA). Despite the acknowledged importance of joint loading in the onset and progression of OA, the load transfer in the three compartments of the intact rabbit knee remains unknown. Therefore, this study was aimed at determining load transfer ...

Total knee arthroplasty following valgus deformity is a challenging procedure due to the unique set of problems that must be addressed. The aim of this study is to determine, with a finite element analysis, the load distribution for an inclined valgus prosthetic balanced knee and to compare these results with ...

The progression of osteoarthritis can be accompanied by depth-dependent changes in the properties of articular cartilage. The objective of the present study was to determine the subsequent alteration in the fluid pressurization in the human knee using a three-dimensional computer model. Only a small compression in the femur-tibia direction was ...

Advanced osteoarthritis of knee joint if bilateral, severely restricts patient mobility. This acts as an aggravating factor for pre existing comorbid elements of metabolical syndrome (MS) like Type II diabetes mellitus and hypertension as patients are unable to carry out therapeutic walks. Successfully implanted total knee arthroplasty (TKA) increases physical ...

The ankle-brachial pressure index (ABI) is widely used as a standard screening method for arterial occlusive lesion above the knee. However, the sensitivity of ABI is low in hemodialysis (HD) patients. Exercise stress (Ex-ABI) may reduce the false negative results. After measuring resting ABI and toe-brachial pressure index (TBI), ankle ...

Measurement of limb occlusion pressure before surgery might lead to the use of a lower tourniquet cuff pressure during surgery and thereby reduce the risk of postoperative pain and complications. The primary aim of this study was to investigate whether the limb-occlusion-pressure method reduces the tourniquet cuff pressure used during ...

Lower body positive pressure (LBPP) treadmills permit significant unweighting of patients and have the potential to enhance recovery following lower limb surgery. We determined the efficacy of an LBPP treadmill in reducing knee forces in vivo. Subjects, implanted with custom electronic tibial prostheses to measure forces in the knee, were ...

Very little is known about how compression bandages lose interface pressure. We hypothesized that the loss of interface pressure is correlated with the slippage of the bandages, and studied the interface pressure and slippage of three bandages over 8 hours. Twenty-Seven legs from 27 healthy volunteers were bandaged with short ...

BACKGROUND:It has been suggested that patellofemoral contact pressures and contact forces may be altered secondary to an opening wedge high tibial osteotomy, yet few data are available that quantify the effect of varying degrees of medial opening wedge osteotomy on the patellofemoral joint contact characteristics. HYPOTHESIS:Opening wedge medial proximal tibial ...

BACKGROUND: Femoropatellar complications are one of the most common problems after total knee arthroplasty (TKA). However, the question of whether to resurface the patella remains controversial. Therefore, we evaluated the kinetics and the retropatellar contact characteristics of patella resurfacing with fixed and gliding surfaces. METHODS: Eight Thiel-embalmed cadaver knees were ...

OBJECTIVE:: Patellofemoral pain syndrome (PFPS), the most common running injury, has been associated with increased internal knee abduction angular impulses (KAAI). Wedged footwear can reduce these impulses during walking, but their effects during running are not well understood. The purpose of this study was to identify the effects of wedged ...

PURPOSE: To demonstrate that lateral to medial patellofemoral force and pressure ratios could be a surrogate marker of retinacular tension and patellar tracking. METHODS: The patellofemoral forces of six knees from three fresh-frozen half-body female cadavers were evaluated with a capacitive sensor under simulated operative conditions in six staged clinical ...

BACKGROUND:Posterior horn detachment (PHD) lesions of the lateral meniscus are commonly associated with acute anterior cruciate ligament (ACL) tears. Multiple surgeons have advocated for repair of this lesion at the time of ACL reconstruction. However, the biomechanical consequences of this lesion and its subsequent repair have not been evaluated. HYPOTHESIS:The ...

PURPOSE: The purposes of this study were to evaluate the effect on tibiofemoral contact mechanics of repair of the posterior root of the medial meniscus and the effect of meniscal allograft transplantation (MAT) with medial collateral ligament (MCL) release at different flexion angles. METHODS: Ten fresh-frozen human cadaveric knees (five ...

BACKGROUND: Celiac plexus block (CPB) can be used for treating intra-abdominal visceral pain syndromes. The celiac plexus is the largest plexus of the sympathetic nervous system. Several nerve blocks have a marked effect on autonomic nervous activity. Furthermore, stellate ganglion block changes cardiac autonomic nervous activity. Thus, CPB could influence ...

ABSTRACT In many species, pneumonectomy results in compensatory growth in the remaining lung. Although the late mechanical consequences of murine pneumonectomy are known, little is known about the anatomic adaptations and respiratory mechanics during compensatory lung growth. To investigate the structural and mechanical changes during compensatory growth, mice were studied ...

Our objectives were to (1) quantify the relationship between daily swallowed volume and amniotic fluid volume (AF volume) in late gestation ovine fetuses and (2) use the resulting regression equation to explore the role of swallowing in regulating AF volume. Daily swallowed volume ranged from 36 to 1963 mL/d while ...

We present an experimental study on the fluorescence behavior of the red fluorescent proteins TagRFP-S, TagRFP-T, mCherry, mOrange2, mStrawberry, and mKO as a function of pressure up to several GPa. TagRFP-S, TagRFP-T, mOrange2, and mStrawberry show an initial increase in fluorescence intensity upon application of pressure above ambient conditions. At ...

Our previous research indicated that dynamic high-pressure microfluidization (DHPM) had a significant effect on the antigenicity of β-lactoglobulin (β-LG). In this study, aggregation and conformational changes subjected to DHPM (0.1-160MPa) were investigated in relation to antigenicity. When DHPM pressure increased from 0.1 to 80MPa, disaggregation of β-LG samples and partial ...

The sympathetic division of the nervous system is critical for maintaining both resting arterial pressure and for producing changes in regional perfusion required by behavioral state changes. A primary determinant of arterial pressure is the level of vasoconstriction within skeletal muscle. It is well established that there is a tight ...

Intraosseous cannulation is an accepted means to achieve vascular access when peripheral venous access is not available. It is common practice to flush the intraosseous cannula with saline prior to establishing infusions. The objective of this study was to evaluate changes in intraosseous pressure during the flush procedure and to ...

Introduction: Sodium balance during hemodialysis is predominantly achieved by ultrafiltration. The additional effect of diffusional sodium losses and gains remains unclear. We recently changed our dialysate acid concentrate supplier, and although both concentrates were instructed to be diluted 1:44, we audited the practical effects of this change.Methods: Review of electronic ...

To understand the physiological effect of intraocular pressure (IOP) on the accommodative mechanism requires a reliable experimental system in which IOP can be manipulated or a rapid IOP change can be induced while simultaneously and continuously measuring IOP and the ocular accommodative changes. In this study, an IOP perfusion and ...

OBJECTIVES: The FloTrac(®) Vigileo(®) (FTV) estimates cardiac output (CO) on the basis of an uncalibrated arterial pressure waveform. To assess the ability of the third-generation of FTV (v.3.02) to track changes in CO following norepinephrine dose adjustment in patients with septic shock, we performed a comparative study using Doppler echocardiography ...

We conducted a prospective study to determine whether divers or hyperbaric chamber attendants could discern chamber pressure--important to protecting blinding if they were to participate in blinded hyperbaric oxygen (HBO2) trials. Experienced divers and chamber attendants were randomized by appointment group to one of four pressure changes. These pressure changes ...

There are few studies on predictive validity of methods to monitor the healing process of pressure ulcers. We evaluated whether the change of DESIGN-R (rating) score could predict subsequent healing, and determined the optimal cutoff points. In a multicenter prospective cohort study, patients were followed until wound healing or censoring. ...

BACKGROUND:Transpulmonary thermodilution (TPTD) is an increasingly popular method used to monitor the complex hemodynamic changes in critically ill children.The purpose of our study was to examine the relationship between transthoracic echocardiographic (TTE) parameters and global hemodynamic variables derived from TPTD and those derived from conventional measurements in infants and neonates ...

AimsWe assessed the haemodynamic changes induced by exposure to high altitude hypoxia and the effects on them of acetazolamide, a drug prescribed to prevent and treat mountain sickness.Methods and resultsIn 42 subjects (21 males, age 36.8 ± 8.9 years) randomized to double blind acetazolamide 250 mg b.i.d. or placebo, pulse ...

Background:Vibro-tactile displays use human skin to convey information from physiological monitors to anesthesiologists, providing cues about changes in the status of the patient. In this investigation, we evaluated, in a real-time clinical environment, the usability and wearability of a novel vibro-tactile display belt recently developed by our group, and determined ...

Understanding the intermolecular interaction potential, V(r), of proteins under the influence of temperature, pressure, and salt concentration is essential for understanding protein aggregation, crystallization, and protein phase behavior in general. Here, we report small-angle x-ray scattering studies on dense lysozyme solutions of high ionic strength as a function of temperature ...

Measurements of the vibrational response of a spherical aluminum shell subject to changes in the interior pressure clearly demonstrate that resonance frequencies shift higher as the pressure is increased. The frequency shift appears to be smaller for longitudinal modes than for bending wave modes. The magnitude of frequency shift is ...

The changes in blood pressure and in the cardiac function were studied in two groups of patients: an elderly group (EG) with 10 healthy normotensive elderly patients, and a young group (YG), with eight normal volunteers. Both groups were provided meals with high contents of lipids (LM), carbohydrates (CM), and ...

BackgroundWe aimed to investigate the association of the change in the ambulatory arterial stiffness index (AASI) with that in carotid-femoral pulse wave velocity (cfPWV) during treatment with antihypertensive medication.MethodsWe enrolled 207 hypertensive patients treated with olmesartan monotherapy for 12 weeks. Patients were randomly assigned to treatment with hydrochlorothiazide (HCTZ; n ...

Periodic density functional theory calculations are performed to study the hydrostatic compression effects on the structure, electronic, and thermodynamic properties of the energetic polyazide 4,4',6,6'-tetra(azido)hydrazo-1,3,5-triazine (TAHT) in the range of 0-100 GPa. At the ambient pressure, the local density approximation/Ceperley-Alder exchange-correlation potential parameterized by Perdew and Zunger relaxed crystal structure ...

J Clin Hypertens (Greenwich). 2012; 14:422-428. ©2012 Wiley Periodicals, Inc. The authors tested the hypothesis that an aggressive antihypertensive treatment is beneficial in protecting against target organ damage (TOD) in patients with type 2 diabetes/prediabetes. The authors enrolled 60 patients with uncontrolled hypertension and diabetes/prediabetes and performed clinic, home, and ...

The purpose of this investigation was to characterize differential right atrial (RA) and ventricular (RV) molecular changes in Ca(2+)-handling proteins consequent to RV pressure overload and hypertrophy in two common, yet distinct models of pulmonary hypertension: dehydromonocrotaline (DMCT) toxicity and pulmonary artery (PA) banding. A total of 18 dogs underwent ...

Our objective was to separate mechanical effects on the circulation that are due to increases in pleural pressure (Ppl) from those due to increases in transpulmonary pressure (Ptp). We used a computational model of the circulation (Magder et al., 2009) which includes four static elastic compartments (systemic and pulmonary arteries ...

Heart rate (HR) and arterial blood pressure (BP) are rapidly and reflexively adjusted as body position and the force / direction of gravity alters. Anomalies in these mechanisms may predispose to circulatory failure during sleep. We analysed the development of two key reflexes involved by undertaking a longitudinal (birth - ...

BACKGROUND: Targeting a higher hemoglobin in patients with chronic kidney disease leads to adverse cardiovascular outcomes, yet the reasons remain unclear. Herein, we sought to determine whether changes in erythropoiesis-stimulating agent (ESA) dose and in hemoglobin were predictive of changes in blood pressure (BP) and whether these changes were associated ...

Cuff-occluded rate of rise of peripheral venous pressure has been proposed to reflect volume changes in experimental studies. The aim of this study was to evaluate changes in cuff-occluded rate of rise of peripheral venous pressure associated with fluid removal by haemodialysis in six adult patients with chronic renal failure ...

BACKGROUND: The main objective of hemodialysis (HD) is to correct the excessive accumulation and abnormal distribution of body fluid. Therefore, changes in the systemic hemodynamic parameters and in the ocular fluid volume and composition can occur during a single HD session. The aim of this study is to evaluate the ...