Prescription of above-knee and below-knee prostheses

Design trends in actuated lower-limb prosthetic systems: a narrative review

INTRODUCTION

Actuated lower limb prostheses, including powered (active) and semi-active (quasi-passive) joints, are endowed with controllable power and/or impedance, which can be advantageous to limb impairment individuals by improving locomotion mechanics and reducing the overall metabolic cost of ambulation. However, an increasing number of commercial and research-focused options have made navigating this field a daunting task for users, researchers, clinicians, and professionals.

AREAS COVERED

The present paper provides an overview of the latest trends and developments in the field of actuated lower-limb prostheses and corresponding technologies. Following a gentle summary of essential gait features, we introduce and compare various actuated prosthetic solutions in academia and the market designed to provide assistance at different levels of impairments. Correspondingly, we offer insights into the latest developments of sockets and suspension systems, before finally discussing the established and emerging trends in surgical approaches aimed at improving prosthetic experience through enhanced physical and neural interfaces.

EXPERT OPINION

The ongoing challenges and future research opportunities in the field are summarized for exploring potential avenues for development of next generation of actuated lower limb prostheses. In our opinions, a closer multidisciplinary integration can be found in the field of actuated lower-limb prostheses in the future.

Sockets for Limb Prostheses: A Review of Existing Technologies and Open Challenges

In the prosthetics field, one of the most important bottlenecks is still the human-machine interface, namely the socket. Indeed, a large number of amputees still rejects prostheses or points out a low satisfaction level, due to a sub-optimal interaction between the socket and the residual limb tissues. The aim of this paper is to describe the main parameters (displacements, stress, volume fluctuations and temperature) affecting the stump-socket interface and reducing the comfort/stability of limb prostheses. In this review, a classification of the different socket types proposed in the literature is reported, together with an analysis of advantages and disadvantages of the different solutions, from multiple viewpoints. The paper then describes the technological solutions available to face an altered distribution of stresses on the residual limb tissues, volume fluctuations affecting the stump overtime and temperature variations affecting the residual tissues within the socket. The open challenges in this research field are highlighted and the possible future routes are discussed, towards the ambitious objective of achieving an advanced socket able to self-adapt in real-time to the complex interplay of factors affecting the stump, during both static and dynamic tasks.

Claimed walking distance of lower limb amputees

PURPOSE

Walking ability in general and specifically for lower limb amputees is of major importance for social mobility and ADL independence. Walking determines prosthesis prescription. The aim of this study was to mathematically analyse factors influencing claimed walking distance of lower limb amputees of 500 m or more.

METHOD

A total of 437 patients returned two questionnaires: the Groningen Questionnaire Problems after Leg Amputation, in which walking distance was assessed, and the RAND 36.

RESULTS

The chance of walking 500 m or more reduced when a transfemoral amputation was performed. The chance reduced even more when phantom pain or stump pains were present. If the amputation was performed because of vascular disease or because of vascular problems because of diabetes the chance reduced again. Independently of these factors, age reduced the chance of walking 500 m or more.

CONCLUSION

The chance of walking 500 m or more reduces with increase in age and a more proximal amputation. The chance reduces even further when the amputation is performed because of diabetes or vascular disease and also if phantom pain and or stump pain is present.

Prosthetic prescription in the Netherlands: an observational study

Prosthetic prescription for lower limb amputees and the methodology used are primarily based on empirical knowledge. Clinical expertise plays an important role that can lead to an adequate prescription; however, a clear evidence based motivation for the choices made cannot be given. This can lead to local prescription variations with regard to overuse or underuse of prosthetic care and a lack of transparency for consumers and health insurance companies. Hence a clinical guideline may lead to a more consistent and efficient clinical practice and thus more uniformly high quality care. The purpose of this study was to get insight into potential similarities in prescription criteria in clinical practice in the Netherlands. Secondly, the authors were interested to know if prosthetic prescription was primarily based on the level of activity or intended use of the prosthesis. As part of the development of a consensus-based clinical guideline a multi-centred, cross-sectional study was carried out in order to observe the prosthetic prescription for a group of lower limb amputees. Therefore prescription data were collected from 151 amputees with trans-femoral amputation, knee disarticulation or trans-tibial amputation. Results of the multiple logistic regression show no relationship between the activity level and any of the variables included in the equation such as the hospital or medical doctor in Physical and Rehabilitation Medicine (MD in P&RM), prosthetic components, age of the amputee or reason of amputation. The criteria used are merely based on the clinical expertise and local experience whereas the actual prescriptions differ from location to location. In conclusion the development of a clinical guideline for prosthetic prescription in lower limb amputation is recommended. The information gained from this observational study will be used in a clinical guideline procedure for prosthetic prescription in the Netherlands.

Transtibial amputation. Prosthetic use and functional outcome

Annually, roughly 80,000 to 100,000 amputations are performed with a total cost of greater than $50,000 per patient. Amputations in general and TTAs in particular are worthy of investigation to provide a cost-effective functional outcome that provides high patient satisfaction. The process of prosthetic selection, functional outcome, and avoidance of common complications begins with preoperative education of the patient and communication with the rehabilitation team. Determining an individual patient's perceptions of the process and his or her desired functional needs can help establish a baseline for prosthetic prescription and patient education. With the apparent difficulty in predicting who will be functional with a prosthesis, it seems prudent to initiate prosthetic training and fitting with all patients who have a moderate potential for use. Because many patients undergoing this operation have significant illness, as judged by the high mortality rate at follow-up, it is important to begin this process early to promote the highest recovery of functional independence. With the continual improvement in prosthetic components and postoperative management, it seems possible for the ill, elderly patient to regain near preoperative functional independence with the use of a prosthesis.

Precision of surface measurements for below-knee residua

OBJECTIVE

To determine the absolute and relative precision of geometric measurements made of below knee (BK) residua and their BK plaster positive casts using calipers, electromagnetic digitizer, optical surface scanner (OSS), and spiral x-ray computed tomography (SXCT).

DESIGN

The experimental measurement protocol for a single measurement session was as follows: Dot markers were placed on the residuum, and volume and distances were measured using water displacement and calipers; residuum was measured using electromagnetic digitizer; residuum was scanned using three-dimensional (3D) OSS; a negative plaster cast of subject's residuum was made; the residuum was scanned using SXCT scanner. These steps were repeated at a second measurement session. Plaster positive casts were constructed and subsequently measured using the same protocol.

PARTICIPANTS

Thirteen adult below-knee amputee volunteers (subjects) participated in the study, and nine subjects returned for a second measurement session. The study group consisted of 9 men and 4 women; 10 Caucasians and 3 African Americans.

RESULTS

Distance measurements for all measurement devices were repeatable within 1% in vivo and within 0.5% on plaster casts; and volumes were within 1% in vivo and within 0.1% on plaster casts. Distance measurements for each device were precise within 3% in vivo and within 1% on plaster casts; and volumes were within 5% in vivo and within 6% on plaster casts when compared with caliper and water displacement measures.

CONCLUSION

These measurement systems were found to be substantially equivalent in terms of repeatability and precision for measurement of lower extremity residua.

Prosthetics, orthotics, and assistive devices. 1. General concepts

This self-directed learning module highlights the general concepts and new advances in the area of orthotics and prosthetics. This general overview is part of the chapter on prosthetics, orthotics, and assistive devices for the Self-Directed Medical Knowledge Program Study Guide for practitioners and trainees in physical medicine and rehabilitation. This section contains essential information on spinal, lower and upper limb orthotics, lower and upper limb prosthetics, juvenile prosthetics, kinesiology, motion analysis, and assistive devices such as canes and crutches. This article establishes a foundation on which the second, third, and fourth articles of this chapter will build. The three articles to follow review newer developments in specialized seating and assistive devices, prosthetics, and the orthotic management of selected disorders.