Joint loading

The aim of this study was to examine the effect of attentional focus instructions on the biomechanical variables associated with the risk of anterior cruciate ligament injury of the knee joint during a drop landing task using a time series analysis. Ten female volleyball players (age: 20.4 ± 0.8 years, height: 169.7 ± 7.1 cm, mass: 57.6 ± 3.1 kg, experience: 6.3 ± 0.8 years) performed landings from a 50 cm height under three different attentional focus conditions: (1) external focus (focus on landing as soft as possible), (2) internal focus (focus on bending your knees when you land), and (3) control (no-focus instruction)...

Older children over 8 years old are at higher risk of elbow joint stiffness after treatment of supracondylar humeral fractures. The objective of this study was to improve the Slongo's external fixation system for treating supracondylar humeral fractures in older children. This would be achieved by increasing fixation strength and providing a theoretical basis through finite element analysis and mechanical testing. A 13-year-old female patient with a history of previous fracture was selected for CT data processing to create a three-dimensional model of the distal humerus fracture...

BACKGROUND: Autonomic dysfunction precedes endothelial dysfunction in Parkinson's disease (PD) and causes blood pressure and circulation abnormalities that are highly disruptive to one's quality of life. While exercise interventions have proven helpful for motor symptoms of PD, improving associated non-motor symptoms is limited. Low-intensity resistance training with blood flow restriction (LIRT-BFR) improves autonomic dysfunction in non-PD patients and high-intensity resistance training (HIRT) is recommended for motor symptom improvements for people with PD (PwPD)...

PURPOSE: This study investigates the impact of elastic improvements to the artificial ankle joint insert on prosthesis biomechanics to reduce the risk of prosthesis loosening in TAR patients. METHODS: CT data of the right ankle was collected from one elderly female volunteer. An original TAR model (Model A) was developed from CT images and the INBONE II implant system. The development of the new inserts adopts an elastic improvement design approach, where different geometric configurations of flexible layers are inserted into the traditional insert...

BACKGROUND: To report a rare occurrence of pigment epitheliopathy associated with choroidal neovasculization as a first manifestation of systemic lupus erythematosus. CASE PRESENTATION: A 54-year-old female, with no prior medical history, sought a second opinion due to sudden drop in vision in her right eye to 20/80. Slit lamp examination was normal. Fundus examination revealed the presence of a subretinal hemorrhage in the macular area. Fundus imaging including optical coherence tomography and fluorescein angiography showed multifocal retinal pigment epitheliopathy associated with choroidal neovascularization (CNV)...

Connective tissue attaches to bone across an insertion with spatial gradients in components, microstructure, and biomechanics. Due to regional stress concentrations between two mechanically dissimilar materials, the insertion is vulnerable to mechanical damage during joint movements and difficult to repair completely, which remains a significant clinical challenge. Despite interface stress concentrations, the native insertion physiologically functions as the effective load-transfer device between soft tissue and bone...

When using end shield shearer to recover end slope coal resources, the stability of the overlying rock slope of the end slope is controlled by leaving coal pillars. Due to the influence of the self weight of the overlying rock layer, the coal pillar will be subjected to eccentric loads, and the influence of eccentric loads needs to be considered in the design of the coal pillar size. With the help of PFC discrete element software, uniaxial compression tests were carried out on coal sample containing hole defects under different degrees of eccentric loads based on the calibration of micro mechanical parameters...

INTRODUCTION: Proximal humerus fractures are usually treated with locking plates, which could present recurrence, screw penetration, joint varization. The push-pull principle was introduced to prevent these risks and showed promising results; a dedicated design was then developed and this feasibility study aims to compare the biomechanical performances of such dedicated push-pull plate with the traditional locking plate using finite elements. MATERIALS AND METHODS: The humerus geometry was obtained from Sawbone CT-scans; the geometries of a traditional locking plate and of the dedicated push-pull one were used...

Prosthetic technology has advanced with the development of powered prostheses to enhance joint function and movement in the absence of native anatomy. However, there are no powered solutions available for hip-level amputees, and most existing hip prostheses are mounted to the front of the prosthetic socket, thereby limiting range of motion. This research introduces a novel laterally mounted powered hip joint (LMPHJ) that augments user movement. The LMPHJ is mounted on the lateral side of the prosthetic socket, positioning the hip joint closer to the anatomical center of rotation while ensuring user safety and stability...

Anterior cruciate ligament (ACL) tears are one of the most common sport-related injuries and occur in greater than 3% of athletes in a four-year window of sports participation. Non-contact injuries are the most common mechanism for ACL injury in elite-level athletes, especially with increased valgus and external rotation of the knee when loading eccentrically in flexion. Because of the immense toll these injuries and their recovery take on athletes especially, optimal treatment has been a subject of great interest for some time...

BACKGROUND: Periprosthetic joint infection after total knee arthroplasty is commonly treated via 2-stage revision utilizing either articulating or static antibiotic cement spacers. While recent literature exhibits a slight functional advantage in favor of articulating spacers, those patients with a history of recurrent infection/multiple revision procedures are frequently excluded from these studies. The purpose of this study was to report infection eradication rates and efficacy of utilizing antibiotic-loaded locked intramedullary nail for infection for the multiply revised, infected total knee arthroplasty...

INTRODUCTION AND IMPORTANCE: Avascular necrosis (AVN), also known as osteonecrosis, refers to the death of bone tissue due to the lack of blood supply. Osteonecrosis in HIV can be a complication of the ART's or the disease itself. CLINICAL PRESENTATION: 47 years old male, HIV positive for 10 years on Antiretroviral-therapy had gradual onset of bilateral hip pain for 6 months, progressively and sharp in nature, aggravated by movement and relieved by resting with reduced range of movement, wheel chair dependent 2 months...

This review evaluates the decision-making framework for using antibiotic-loaded cement (ALC) in the management of prosthetic joint infection (PJI). Drawing on available literature, we offer orthopaedic surgeons a guided discussion on several critical considerations. First, we explore the impact of antibiotic-loading on the mechanical properties of polymethylmethacrylate (PMMA) cement, assessing both strength and durability. We then explore the optimal antibiotic dosage to load into cement, aiming to achieve effective local concentrations for infection control without compromising mechanical stability...

As a solution to restore knee function and reduce pain, the demand for Total Knee Arthroplasty (TKA) has dramatically increased in recent decades. The high rates of dissatisfaction and revision makes it crucially important to understand the relationships between surgical factors and post-surgery knee performance. Tibial implant alignment in the sagittal plane (i.e., posterior tibia slope, PTS) is thought to play a key role in quadriceps muscle forces and contact conditions of the joint, but the underlying mechanisms and potential consequences are poorly understood...

Intra-articular injection of drugs is an effective strategy for osteoarthritis (OA) treatment. However, the complex microenvironment and limited joint space result in rapid clearance of drugs. Herein, a nanogel-based strategy was proposed for prolonged drug delivery and microenvironment remodeling. Nanogel was constructed through functionalization of hyaluronic acid (HA) by amide reaction on the surface of Kartogenin (KGN)-loaded zeolitic imidazolate framework-8 (denoted as KZIF@HA). Leveraging the inherent hydrophilicity of HA, KZIF@HA spontaneously forms nanogels, ensuring extended drug release in the OA microenvironment...

BACKGROUND: The principle of joint reconstruction surgery is to try to recreate the native joint biomechanics and stability. With respect to acromioclavicular joint (ACJ) surgery, much focus to date has been on restoring the superoinferior stability. There is concern that persistent horizontal instability following ACJ reconstruction could lead to poorer patient outcomes; therefore, we evaluated whether acromioclavicular (AC) ligament repair offers improved horizontal stability in conjunction with ACJ reconstruction...

Robotic lower-limb prostheses, with their actively powered joints, may significantly improve amputee users' mobility and enable them to obtain healthy-like gait in various modes of locomotion in daily life. However, timely recognition of the amputee users' locomotive mode and mode transition still remains a major challenge in robotic lower-limb prosthesis control. In the paper, the authors present a new multi-dimensional dynamic time warping (mDTW)-based intent recognizer to provide high-accuracy recognition of the locomotion mode/mode transition sufficiently early in the swing phase, such that the prosthesis' joint-level motion controller can operate in the correct locomotive mode and assist the user to complete the desired (and often power-demanding) motion in the stance phase...

Malalignment of the lower limb, distal tibia, foot, and hindfoot can all contribute to altered biomechanics in the ankle joint, resulting in increased focal pressure. The development of some osteochondral lesions of the ankle joint may share a similar pathophysiology, where eccentric loading to the talus or tibia within the ankle joint can lead to cartilage injury or adaptive changes. While the association between malalignment and the development of osteochondral lesions of the ankle joint may seem intuitive, the impact of realignment procedures on these lesions and patient symptoms remains a relatively underexplored topic in the literature...

OBJECTIVE: To perform non-invasive Electroarthrography (EAG) on live horses and establish relationships between EAG and direct measurements of cartilage streaming potentials in weight bearing areas of the equine metacarpophalangeal joint. DESIGN: EAG was performed bilaterally on the metacarpophalangeal joints of live horses (n=3). Separate experiments used metacarpophalangeal joint explants (n=11) to measure EAG obtained during simulated loading followed by direct measurements of cartilage streaming potentials on joint surfaces using the Arthro-BST probe...

Condylar stress fracture of the distal end of the third metacarpal/metatarsal (MC3/MT3) bones is a major cause of Thoroughbred racehorse injury and euthanasia worldwide. Functional adaptation to exercise and fatigue damage lead to structural changes in the subchondral bone that include increased modeling (resulting in sclerotic bone tissue) and targeted remodeling repair (resulting in focal resorption spaces in the parasagittal groove). Whether these focal structural changes, as detectable by standing computed tomography (sCT), lead to elevated strain at the common site of condylar stress fracture has not been demonstrated...