Comparison of Sagittal Plane Stiffness of Nonarticulated Pediatric Ankle-Foot Orthoses Designed to be Rigid.

Introduction: When studying the effect of ankle-foot orthoses (AFOs) on gait, it is important to know their sagittal plane stiffness. However, there are no established thresholds for stiffness of non-articulated AFOs designed to be rigid. If wanting to implement published algorithms for ankle-foot orthosis-footwear combinations (AFO-FCs), the AFOs must be equally as stiff as those of the developer of the published AFO-FC algorithms.

The feasibility and validity of a wearable sensor system to assess the stability of high-functioning lower-limb prosthesis users.

Introduction: Lower-limb prosthesis users (LLPUs) experience increased fall risk due to gait and balance impairments. Clinical outcome measures are useful for measuring balance impairment and fall risk screening but suffer from limited resolution and ceiling effects. Recent advances in wearable sensors that can measure different components of gait stability may address these limitations.

Unilateral above-knee amputees achieve symmetric mediolateral ground reaction impulse in walking using an asymmetric gait strategy.

The ability to sustain steady straight-ahead walking is one goal of gait rehabilitation for individuals with unilateral above-knee (UAK) amputation. Despite the morphological and musculoskeletal asymmetry resulting from unilateral limb loss, the mediolateral ground-reaction-impulse (GRI) should be counterbalanced between the affected and unaffected limbs during straight-ahead walking. Therefore, we investigated the strategies of mediolateral ground-reaction-force (GRF) generation adopted by UAK prosthesis users walking along a straight path.

Stochastic Resonance Reduces Sway and Gait Variability in Individuals With Unilateral Transtibial Amputation: A Pilot Study.

Sub-threshold (imperceptible) vibration, applied to parts of the body, impacts how people move and perceive our world. Could this idea help someone who has lost part of their limb? Sub-threshold vibration was applied to the thigh of the affected limb of 20 people with unilateral transtibial amputation. Vibration conditions tested included two noise structures: pink and white.

Using mechanical testing to assess the effect of lower-limb prosthetic socket texturing on longitudinal suspension.

To function effectively, a lower limb prosthetic socket must remain securely coupled to the residual limb during walking, running and other activities of daily living; this coupling is referred to as suspension. When this coupling is insufficient longitudinal pistoning of the socket relative to the residual limb occurs. Increasing friction of the socket/liner interface may improve socket suspension and textured sockets may be fabricated relatively easily with 3D printing.

Using mechanical testing to assess texturing of prosthetic sockets to improve suspension in the transverse plane and reduce rotation.

Creating a secure and comfortable linkage between the residual limb and prosthetic socket in persons with lower limb amputation is a critical factor for successful rehabilitation, including ambulation and other activities of daily living. Unwanted rotation within the socket can be a clinical problem for prosthesis users. One way of addressing issues experienced with transverse plane control of the socket may be through increased friction interface forces.

Asymmetry of mass and motion affects the regulation of whole-body angular momentum in individuals with upper limb absence.

Background: There is a high fall prevalence in individuals with upper limb absence, which may be related to a momentum imbalance resulting from the loss of all or part of one arm. The purpose of this study was to characterise whole-body angular momentum in individuals with upper limb absence during walking, and determine the effect of restoring the mass and inertial properties of the impaired side with a mock prosthesis.

Methods: Ten individuals with unilateral upper limb absence walked at self-selected speeds, with and without a mock prosthesis.

Effects of Upper Limb Loss or Absence and Prosthesis Use on Postural Control of Standing Balance.

Objective: Persons with upper limb loss or absence experience a high prevalence of falls. Although upper limb prostheses help perform upper limb tasks, fall likelihood increases by six times with prosthesis use. The effects of upper limb loss or absence and prosthesis use on postural control are poorly documented.

Effects of upper limb loss and prosthesis use on proactive mechanisms of locomotor stability.

Persons with upper limb loss (ULL) experience a high prevalence of falls, with the majority of falls occurring when walking. This issue may be related to altered arm dynamics, which play an important role in proactive mechanisms of locomotor stability. This study investigated effects of ULL and prosthesis use on proactive stability mechanisms, particularly if matching the mass and inertia of the impaired limb to the sound limb would enhance locomotor stability.

Do Upper Limb Loss and Prosthesis Use Affect Lower Limb Gait Dynamics?

Introduction: Intentional interruption of upper and lower limb coordination of able-bodied subjects alters their gait biomechanics. However, the effect of upper-limb loss (ULL) on lower-limb gait biomechanics is not fully understood. The aim of this secondary study was to perform a follow-up analysis of a previous dataset to characterize the spatiotemporal parameters and lower-limb kinematics and kinetics of gait for persons with ULL when wearing and not wearing an upper limb prosthesis (ULP).

Technique modifications for a suction suspension version of the Northwestern University Flexible Sub-Ischial Vacuum socket: The Northwestern University Flexible Sub-Ischial Suction socket.

Background And Aim:: Development of a passive suction version of the Northwestern University Flexible Sub-Ischial Vacuum socket would expand application of sub-ischial sockets to a larger proportion of persons with transfemoral amputation. While active vacuum suspension provides more positive coupling of the residual limb to the prosthetic socket, there are circumstances when use of active vacuum is not appropriate or feasible. Therefore, this technical note describes the technique modifications required to cast, fabricate, and fit a passive suction version of the Northwestern University Flexible Sub-Ischial Vacuum socket (i.

Stakeholder perspectives for possible residual limb monitoring system for persons with lower-limb amputation.

To gather ideas from lower-limb prosthesis users and certified prosthetists regarding possible residual limb monitoring system features and data presentation. We also gathered information on the type of residual limb problems typically encountered, how they currently manage those problems, and their ideas for methods to better manage them. Two focus groups were held; one with certified prosthetists and another with lower-limb prosthesis users.

Change in residual limb size over time in the NU-FlexSIV socket: A case study.

Background:: This case study represented a unique opportunity wherein a long-time user of sub-ischial sockets had kept nearly every socket he wore for a decade. This individual let us borrow these sockets so we could digitize them and indirectly assess change in residual limb size over time by calculating changes in socket volume and circumferences over time.

Case Description And Methods:: Over a decade, the subject maintained a relatively stable body weight of 84-88 kg and received nine sub-ischial sockets.

Considering passive mechanical properties and patient user motor performance in lower limb prosthesis design optimization to enhance rehabilitation outcomes.

Background: Selection of prosthesis mechanical characteristics to restore function of persons with lower-limb loss can be framed as an optimization problem to satisfy a given performance objective. However, the choice of a particular objective is critical, and considering only device and generalizable outcomes across users without accounting for inherent motor performance likely restricts a given patient from fully realizing the benefits of a prosthetic intervention.

Objectives: This review presents methods for optimizing passive below-knee prosthesis designs to maximize rehabilitation outcomes and how considerations on patient motor performance may enhance these outcomes.

A systematic review describing incidence rate and prevalence of dysvascular partial foot amputation; how both have changed over time and compare to transtibial amputation.

Background: Partial foot amputation (PFA) is a common consequence of advanced peripheral vascular disease. Given the different ways incidence rate and prevalence data have been measured and reported, it is difficult to synthesize data and reconcile variation between studies. As such, there is uncertainty in whether the incidence rates and prevalence of PFA have increased over time compared to the decline in transtibial amputation (TTA).

How a diverse research ecosystem has generated new rehabilitation technologies: Review of NIDILRR's Rehabilitation Engineering Research Centers.

Over 50 million United States citizens (1 in 6 people in the US) have a developmental, acquired, or degenerative disability. The average US citizen can expect to live 20% of his or her life with a disability. Rehabilitation technologies play a major role in improving the quality of life for people with a disability, yet widespread and highly challenging needs remain.

Skill assessment in upper limb myoelectric prosthesis users: Validation of a clinically feasible method for characterising upper limb temporal and amplitude variability during the performance of functional tasks.

Upper limb myoelectric prostheses remain challenging to use and are often abandoned. A proficient user must be able to plan/execute arm movements while activating the residual muscle(s), accounting for delays and unpredictability in prosthesis response. There is no validated, low cost measure of skill in performing such actions.

While Mortality Rates Differ After Dysvascular Partial Foot and Transtibial Amputation, Should They Influence the Choice of Amputation Level?

Although there is strong evidence to show that the risk of dying after transtibial amputation is higher than partial foot amputation, we are concerned by the implication that amputation level influences mortality, and that such interpretations of the evidence may be used to inform decisions about the choice of amputation level. We argue that the choice of partial foot or transtibial amputation does not influence the risk of mortality. The highest mortality rates are observed in studies with older people with more advanced systemic disease and multiple comorbidities.

Effect of foot and ankle immobilization on able-bodied gait as a model to increase understanding about bilateral transtibial amputee gait.

Background: The anatomical foot-ankle complex facilitates advancement of the stance limb through foot rockers and late-stance power generation during walking, but this mechanism is altered for persons with bilateral transtibial amputation when using passive prostheses.

Objectives: To study the effects of bilateral foot and ankle immobilization on able-bodied gait to serve as a model for understanding gait of persons with bilateral transtibial amputation and associated compensatory mechanisms.

Study Design: Comparative analysis.

Northwestern University Flexible Subischial Vacuum Socket for persons with transfemoral amputation: Part 2 Description and Preliminary evaluation.

Background: Current transfemoral prosthetic sockets are problematic as they restrict function, lack comfort, and cause residual limb problems. Development of a subischial socket with lower proximal trim lines is an appealing way to address this problem and may contribute to improving quality of life of persons with transfemoral amputation.

Objectives: The purpose of this study was to illustrate the use of a new subischial socket in two subjects.

Quantification of rectifications for the Northwestern University Flexible Sub-Ischial Vacuum Socket.

Background: The fit and function of a prosthetic socket depend on the prosthetist's ability to design the socket's shape to distribute load comfortably over the residual limb. We recently developed a sub-ischial socket for persons with transfemoral amputation: the Northwestern University Flexible Sub-Ischial Vacuum Socket.

Objective: This study aimed to quantify the rectifications required to fit the Northwestern University Flexible Sub-Ischial Vacuum Socket to teach the technique to prosthetists as well as provide a computer-aided design-computer-aided manufacturing option.

Northwestern University Flexible Subischial Vacuum Socket for persons with transfemoral amputation-Part 1: Description of technique.

Background: Current transfemoral prosthetic sockets restrict function, lack comfort, and cause residual limb problems. Lower proximal trim lines are an appealing way to address this problem. Development of a more comfortable and possibly functional subischial socket may contribute to improving quality of life of persons with transfemoral amputation.