Remote monitoring of lower-limb prosthetic socket fit using wireless technologies

Feasibility testing of a novel prosthetic socket sensor system

PURPOSE

Poorly fitting prosthetic sockets contribute to decreased quality of life, health, and well-being for persons with amputations. Therefore, improved socket fit is a high clinical priority.

METHODS

In this study, we describe the design and testing of a novel sensor system that can be incorporated into a prosthetic socket to measure distal end weight bearing in the socket and can alert a prosthesis user if poor socket fit is suspected. We present the results of testing this device with three Veterans who were new prosthesis users and three Veterans who were experienced prosthesis users.

RESULTS AND CONCLUSIONS

We collected sensor data during walking trials while participants wore varying numbers of sock plies and qualitative feedback on the design of the socket fit sensor system. For analysis, peak sensor measurements during walking cycles were identified and combined with socket fit data (i.e., a clinician-determined level of "good," "too tight," or "too loose" and the number of sock ply worn each trial). We found consistent relationships between peak sensor measurements and socket fit in our sample. Also, all users expressed an interest in the device, highlighting its potential benefits during early prosthesis training.Implications for RehabilitationEnsuring socket fit is challenging for many prosthesis users.A novel wearable sensor system can be used to identify socket fit issues for some prosthesis users.This type of system could be most helpful for new prosthesis users and those with sensory and cognitive challenges.

Techniques for Interface Stress Measurements within Prosthetic Sockets of Transtibial Amputees: A Review of the Past 50 Years of Research

The distribution of interface stresses between the residual limb and prosthetic socket of a transtibial amputee has been considered as a direct indicator of the socket quality fit and comfort. Therefore, researchers have been very interested in quantifying these interface stresses in order to evaluate the extent of any potential damage caused by the socket to the residual limb tissues. During the past 50 years a variety of measurement techniques have been employed in an effort to identify sites of excessive stresses which may lead to skin breakdown, compare stress distributions in various socket designs, and evaluate interface cushioning and suspension systems, among others. The outcomes of such measurement techniques have contributed to improving the design and fitting of transtibial sockets. This article aims to review the operating principles, advantages, and disadvantages of conventional and emerging techniques used for interface stress measurements inside transtibial sockets. It also reviews and discusses the evolution of different socket concepts and interface stress investigations conducted in the past five decades, providing valuable insights into the latest trends in socket designs and the crucial considerations for effective stress measurement tools that lead to a functional prosthetic socket.

Self-reported prosthetic sock use among persons with transtibial amputation

BACKGROUND

Daily changes in the shape and size of the residual limb affect prosthetic socket fit. Prosthetic socks are often added or removed to manage changes in limb volume. Little has been published about how persons with transtibial amputations use socks to manage diurnal changes in volume and comfort.

OBJECTIVES

To investigate prosthetic sock use with a customized, self-report questionnaire.

STUDY DESIGN

Cross-sectional survey.

METHODS

Persons with transtibial amputation reported number, thickness, and timing of socks used over a 14-day period.

RESULTS

Data from 23 subjects (16 males and 7 females) were included. On average, socks were changed less than once per day (0.6/day) and ply increased over the day (4.8-5.5 ply). Subjects wore prostheses significantly longer (15.0-14.1 h, p = 0.02) and changed socks significantly more often (0.6/day-0.4/day, p = 0.03) on weekdays compared to weekends. Participants were also divided into two subgroups: those who used socks to manage limb volume and those who used socks for socket comfort. Sock use did not differ (p > 0.05) between subgroups.

CONCLUSIONS

Sock changes are infrequent among persons with lower limb loss. Initial, verbal reports of sock use were often inconsistent with data measured by logs. Tools (e.g. sock logs or objective instruments) to better understand sock-use habits among persons with limb loss are needed.

CLINICAL RELEVANCE

Knowledge of prosthetic patients' sock use may help practitioners enhance volume management strategies or troubleshoot fitting issues. Results showed that subjects generally added socks to account for volume loss, and end-of-day sock thickness frequently exceeded 5 ply. Use of sock logs in clinical practice may facilitate improved residual limb health.