Design and validation of finite element models for the assessment of post-fixation distal femur fracture motion.

Fracture site motion is thought to play an important role in the healing of complex fractures of the distal femur via mechanotransduction. Measuring this motion in vivo is challenging, and this has led researchers to turn to finite element modeling approaches to gain insights into the mechanical environment at the fracture site. Developing a systematic understanding of the effect of different model choices for distal femur fractures may allow more accurate prediction of fracture site motion from these types of simulations.

Should individuals with unilateral transtibial amputation carry a load on their intact or prosthetic side?

Carrying side loads often occurs during activities of daily living. As walking is most unstable mediolaterally, side load carriage may further compromise gait biomechanics, especially for transtibial amputees (TTAs). This study investigated the effects of side load carriage on gait kinetics during steady-state walking to determine which side, intact or prosthetic, TTAs should carry a load.

The influence of load carriage and prosthetic foot type on individual muscle and prosthetic foot contributions to body support and propulsion.

Individuals with transtibial amputation (TTA) experience altered gait mechanics, which are primarily attributed to the functional loss of the ankle plantarflexors. The plantarflexors contribute to body support and propulsion and play an important role in adapting to different load carriage conditions. However, how muscle function is altered across different prosthetic foot types and load carriage scenarios for individuals with TTA remains unclear.

Kinematic Sequence Differences Between Trained Baseball Players and Untrained Adolescent Individuals.

An overhead throwing motion is a common gross motor skill often taught in early childhood to improve physical activity participation. Yet, research investigating motor efficiency in overhead throws often focuses on improving performance in trained individuals. This project compares kinematic sequencing between trained and untrained youth.

The effect of prosthetic foot stiffness category on intact limb knee loading associated with osteoarthritis in people with transtibial amputation.

Lower limb prosthesis users are at an increased risk of developing osteoarthritis in their intact knee. There is a scarcity of literature examining how the stiffness properties of commercially available prosthetic feet impact gait mechanics, including knee loading biomechanical variables that have been associated with the development of osteoarthritis. This study aimed to isolate the effect of commercial prosthetic foot stiffness on intact knee loading, prosthetic foot-ankle biomechanics, and user perception.

A robotic emulator for the systematic exploration of transtibial biarticular prosthesis designs.

People with transtibial limb loss frequently experience suboptimal gait outcomes. This is partly attributable to the absence of the biarticular gastrocnemius muscle, which plays a unique role in walking. Although a recent surge of biarticular prostheses aims to restore gastrocnemius function, the broad design space and lack of consensus on optimal hardware and control strategies present scientific and engineering challenges.

Ankle osteoarthritis: Toward new understanding and opportunities for prevention and intervention.

The ankle infrequently develops primary osteoarthritis (OA), especially when compared to the hip and the knee. Ankle OA instead generally develops only after trauma. The consequences of end-stage ankle OA can nonetheless be extremely debilitating, with impairment comparable to that of end-stage kidney disease or congestive heart failure.

Racial disparities in prosthesis abandonment and mobility outcomes after lower limb amputation from a dysvascular etiology in a veteran population.

Background: Non-Hispanic Black (NHB) individuals have higher rates of amputation and increased risk of a transfemoral amputation due to dysvascular disease than non-Hispanic White (NHW) individuals. However, it is unclear if NHB individuals have differences in prosthesis use or functional outcomes following an amputation.

Objective: To determine if there are racial disparities in prosthesis abandonment and mobility outcomes in veterans who have undergone their first major unilateral lower extremity amputation (LEA) due to diabetes and/or peripheral artery disease.

Development of the AMPDECIDE Decision Aid to Facilitate Shared Decision Making in Patients Facing Amputation Secondary to Chronic Limb Threatening Ischemia.

Introduction: We developed a patient decision aid to enhance patient participation in amputation level decision making when there is a choice between a transmetatarsal or transtibial amputation.

Methods: In accordance with International Patient Decision Aid Standards, we developed an amputation level patient decision aid for patients who are being considered for either a transmetatarsal or transtibial amputation, incorporating qualitative literature data, quantitative literature data, qualitative provider and patient interviews, expert panel input and iterative patient feedback.

Results: The rapid qualitative literature review and qualitative interviews identified five domains outcome priority domains important to patients facing amputation secondary to chronic limb threatening ischemia: 1) the ability to walk, 2) healing and risk for reamputation, 3) rehabilitation program intensity, 4) ease of prosthetic use, and 5) limb length after amputation.

A patient-centered 'test-drive' strategy for ankle-foot orthosis prescription: Protocol for a randomized participant-blinded trial.

Background: Ankle-foot orthoses (AFOs) are commonly used to overcome mobility limitations related to lower limb musculoskeletal injury. Despite a multitude of AFOs to choose from, there is scant evidence to guide AFO prescription and limited opportunities for AFO users to provide experiential input during the process. To address these limitations in the current prescription process, this study evaluates a novel, user-centered and personalized 'test-drive' strategy using a robotic exoskeleton ('AFO emulator') to emulate commercial AFO mechanical properties (i.

A method for automated masking and plantar pressure analysis using segmented computed tomography scans.

Background: Plantar pressure, a common gait and foot biomechanics measurement, is typically analyzed using proprietary commercial software packages. Regional plantar pressure analysis is often reported in terms of underlying bony geometry, and recent advances in image processing and accessibility have made computed tomography, radiographs, magnetic resonance imaging, or other imaging methods more popular for incorporating bone analyses in biomechanics.

Research Question: Can a computed tomography-based regional mask provide comparable regional analysis to commercial plantar pressure software and can the increased flexibility of an in-house method obtain additional insight from common measurements?

Methods: A plantar pressure analysis method was developed based on bony geometry from computed tomography scans to calculate peak pressure, pressure time integral incorporating sub-peak values, force time integral, pressure gradient, and pressure gradient angle.

Sagittal and transverse ankle angle coupling can influence prosthetic socket transverse plane moments.

Introduction: The intact foot and ankle comprise a complex set of joints that allow rotation in multiple planes of motion. Some of these motions are coupled, meaning rotation in one plane induces motion in another. One such coupling is between the sagittal and transverse planes.

The impact of climate change and related extreme weather on people with limb loss.

The human health consequences of climate change and extreme weather events are well documented. Published literature details the unique effects and necessary adaptation planning for people with physical disabilities in general; however, the specific impacts and plans for people with limb loss have yet to be explored. In this article, we discuss the impacts related to threats due to heat, cold, severe storms, and power outages.

The Effect of Prosthetic Limb Sophistication and Amputation Level on Self-reported Mobility and Satisfaction With Mobility.

Objective: To determine if lower limb prosthesis (LLP) sophistication is associated with patient-reported mobility and/or mobility satisfaction, and if these associations differ by amputation level.

Design: Cohort study that identified participants through a large national database and prospectively collected self-reported patient outcomes.

Setting: The Veterans Administration (VA) Corporate Data Warehouse, the National Prosthetics Patient Database, participant mailings, and phone calls.

A new approach to a powered knee prosthesis: Layering powered assistance onto strictly passive prosthesis behavior.

This article describes a novel approach to the control of a powered knee prosthesis where the control system provides passive behavior for most activities and then provides powered assistance only for those activities that require them. The control approach presented here is based on the categorization of knee joint function during activities into four behaviors: resistive stance behavior, active stance behavior, ballistic swing, and non-ballistic swing. The approach is further premised on the assumption that healthy non-perturbed swing-phase is characterized by a ballistic swing motion, and therefore, a replacement of that function should be similarly ballistic.

Subject-specific material properties of the heel pad: An inverse finite element analysis.

Individuals with diabetes are at a higher risk of developing foot ulcers. To better understand internal soft tissue loading and potential treatment options, subject-specific finite element (FE) foot models have been used. However, existing models typically lack subject-specific soft tissue material properties and only utilize subject-specific anatomy.

Normal and malaligned talonavicular fusion alters cadaveric foot pressure and kinematics.

Talonavicular (TN) fusion is a common treatment for TN arthritis or deformity correction. There is incongruous evidence regarding remaining motion at the talocalcaneal and calcaneocuboid joints after TN fusion. Additionally, the effects of a malaligned TN fusion are not well understood and alignment of the fusion may be important for overall foot integrity.

Transfemoral limb loss modestly increases the metabolic cost of optimal control simulations of walking.

Background: In transtibial limb loss, computer simulations suggest that the maintenance of muscle strength between pre- and post-limb loss can maintain the pre-limb loss metabolic cost. These results are consistent with comparable costs found experimentally in select cases of high functioning military service members with transtibial limb loss. It is unlikely that similar results would be found with transfemoral limb loss, although the theoretical limits are not known.

Exploring the mechanical properties of 3D-printed multilayer lattice structures for use in accommodative insoles.

Full-contact insoles fabricated from multilayer foams are the standard of care (SoC) for offloading and redistributing high plantar pressures in individuals with diabetes at risk of plantar ulceration and subsequent lower limb amputation. These devices have regional variations in total thickness and layer thickness to create conformity with a patient's foot. Recent work has demonstrated that metamaterials can be tuned to match the mechanical properties of SoC insole foams.

Prospective Multicenter Study of Salto Talaris Ankle Arthroplasty With Minimum 4-Year Follow-Up.

Background: Total ankle arthroplasty (TAA) continues to be investigated as a primary treatment for end-stage ankle arthritis. The objective of this study is to report mid- to long-term results of the Salto Talaris TAA using prospectively collected patient-reported outcomes and implant survival rates with 4- to 13-year follow-up.

Methods: This was a retrospective study of prospectively collected data from 2 multicenter cohort studies from 3 centers.

Healthcare segregation in orthopedic surgery: A statewide analysis of American Indian and Alaska Native patients.

Significant health disparities have been described for American Indian and Alaska Native (AIAN) patients undergoing various surgical procedures, however, research into healthcare segregation within orthopedic surgery has been limited. In this study, our purpose was to assess if AIAN patients were more likely to be treated by lower-volume surgeons and at lower-volume hospitals. AIAN and White patients who underwent one of four common orthopedic procedures (knee or hip arthroplasty, femur or tibia repair) were identified from a Washington state inpatient database.