Issues Faced by Prosthetists and Physiotherapists During Lower-Limb Prosthetic Rehabilitation: A Thematic Analysis

Successful prosthetic rehabilitation is essential to improve the physical and mental outcomes of people with lower-limb amputation. Evaluation of prosthetic services from a prosthesis user perspective have been published and commissioned by the national bodies, however, the perspectives of clinicians working with service users during rehabilitation have not to date been sought. We sought to determine factors impacting lower-limb prosthetic rehabilitation from a clinician's perspective to inform studies focusing on prosthetic and socket design and fitting. Six clinician (2 prosthetists, 4 physiotherapists) interviewees were self-selected from a survey exploring issues and frustrations during lower-limb prosthetic rehabilitation. Semi-structured interviews explored the impactors on and frustrations with rehabilitation and the prosthetic socket. A thematic analysis was subsequently conducted to identify themes in the responses. Five themes were identified: Service Disparity, Body Impactors, Consequences of Ill-Fit, Prosthesis Irritants, and Limitations of Practice. Each theme, though distinct, relates to the others either as a cause or consequence and should be viewed as such. Addressing the themes will have benefits beyond the issues addressed but also expand into the other themes. This study provides an insight into the clinician perspectives on lower-limb prosthetic rehabilitation, which has not been formally documented to date.

The Use of Smartphone Photogrammetry to Digitise Transtibial Sockets: Optimisation of Method and Quantitative Evaluation of Suitability

The fit of a lower limb prosthetic socket is critical for user comfort and the quality of life of lower limb amputees. Sockets are conventionally produced using hand-crafted patient-based casting techniques. Modern digital techniques offer a host of advantages to the process and ultimately lead to improving the lives of amputees. However, commercially available scanning equipment required is often expensive and proprietary. Smartphone photogrammetry could offer a low cost alternative, but there is no widely accepted imaging technique for prosthetic socket digitisation. Therefore, this paper aims to determine an optimal imaging technique for whole socket photogrammetry and evaluate the resultant scan measurement accuracy. A 3D printed transtibial socket was produced to create digital and physical twins, as reference models. The printed socket was photographed from 360 positions and simplified genetic algorithms were used to design a series of experiments, whereby a collection of photos were processed using Autodesk ReCap. The most fit technique was used to assess accuracy. The accuracy of the socket wall volume, surface area and height were 61.63%, 99.61% and 99.90%, respectively, when compared to the digital reference model. The scanned model had a wall thickness ranging from 2.075 mm at the top to 7.758 mm towards the base of the socket, compared to a consistent thickness of 2.025 mm in the control model. The technique selected did not show sufficient accuracy for clinical application due to the degradation of accuracy nearer to the base of the socket interior. However, using an internal wall thickness estimation, scans may be of sufficient accuracy for clinical use; assuming a uniform wall thickness.

Within-subjects Effects of Standardized Prosthetic Socket Modifications on Physical Function and Patient-Reported Outcomes

• Background: Among the challenges of living with lower limb loss is the increased risk of long-term health problems that can be either attributed directly to the amputation surgery and/or prosthetic rehabilitation or indirectly to a disability-induced sedentary lifestyle. These problems are exacerbated by poorly fit prosthetic sockets. There is a knowledge gap regarding how the socket design affects in-socket mechanics, and how in-socket mechanics affect patient-reported comfort and function. The objectives of this study are: 1) to gain a better understanding of how in-socket mechanics of the residual limb in transfemoral amputees are related to patient-reported comfort and function, 2) to identify clinical tests that can streamline the socket design process, and 3) to evaluate the efficacy and cost of a novel, quantitatively informed socket optimization process.• Methods: Users of transfemoral prostheses will be asked to walk on a treadmill wearing their current socket plus 8 different check sockets with designed changes in different structural measurements that are likely to induce changes in residual limb motion, skin strain, and pressure distribution within the socket. Dynamic biplane radiography and pressure sensors will be used to measure in-socket residual limb mechanics. Patient-reported outcomes will also be collected after wearing each socket. The effects of in-socket mechanics on both physical function and patient-reported outcomes (aim 1) will be assessed using a generalized linear model. Partial correlation analysis will be used to examine the association between research grade measurements and readily available clinical measurements (aim 2). In order to compare the new quantitative design method to the Standard of Care, patient reported outcomes and cost will be compared between the two methods, utilizing the Wilcoxon Mann-Whitney non-parametric test (aim 3).• Discussion: Knowledge on how prosthetic socket modifications affect residual bone and skin biomechanics itself can be applied to devise future socket designs, and the methodology can be used to investigate and improve such designs, past and present. Apart from saving time and costs, this may result in better prosthetic socket fit for a large patient population, thus increasing their mobility, participation, and overall health-related quality of life. • Trial registration: clinicaltrials.gov: NCT05041998

Strength testing of low-cost 3D-printed transtibial prosthetic socket

Measurement and production of traditional prosthetic sockets are time-consuming, labor-intensive, and highly dependent on the personnel involved. An alternative way to make prostheses is using computer-aided design (CAD) and computer-aided manufacturing (CAM). Fused Filament Fabrication (FFF) may be an alternative to make low-cost prosthetic sockets. This study investigates the tensile properties of potential printing materials suitable for FFF according to ISO527 (Standard Test Method for Tensile Properties of Plastics). To ensure that FFF-printed sockets are safe for patient usage, the structural integrity of the 3D-printed prosthesis will be investigated according to ISO10328 (International Standard Structural Testing of Lower Limb Prostheses). Tough PLA was the most suitable print material according to ISO 527 testing. The Tough PLA printed socket completed 2.27 million cycles and a static test target value of 4025 N. Future research remains necessary to continue testing new potential materials, improve print settings, and improve the socket design for the production of FFF-printed transtibial prosthetic sockets. FFF using Tough PLA can be used to create transtibial prostheses that almost comply with the International Standard for Structural Testing of Lower Limb Prostheses.

Bacterial Adhesion on Prosthetic and Orthotic Material Surfaces

Prosthetic and orthotic parts, such as prosthetic socket and inner sides of orthoses, are often in contact with human skin, giving bacteria the capability to adhere and form biofilms on the materials of those parts which can further cause infections. The purpose of this study was to determine the extent of bacterial adhesion of Staphylococcus aureus and Staphylococcus epidermidis on twelve different prosthetic and orthotic material surfaces and how roughness, hydrophobicity, and surface charge of this materials affect the adhesion. The roughness, contact angle, zeta potential of material surfaces, and adhesion rate of Staphylococcus aureus and Staphylococcus epidermidis were measured on all twelve prosthetic and orthotic materials, i.e., poly(methyl methacrylate), thermoplastic elastomer, three types of ethylene polyvinyl acetates (pure, with low-density polyethylene and with silver nanoparticles), silicone, closed-cell polyethylene foams with and without nanoparticles, thermo and natural cork, and artificial and natural leather. The greatest degree of adhesion was measured on both closed-cell polyethylene foams, followed by artificial thermo cork and leather. The lowest adhesion extent was observed on ethylene-vinyl acetate. The bacterial adhesion extent increases with the increasing surface roughness. Smaller deviations of this rule are the result of the surface’s hydrophobicity and charge.

A Visual Feedback Tool for Quantitative Pressure Monitoring in Lower-Limb Prosthetic Sockets

Obtaining a good socket fit is an iterative process dependent on the skill and experience of the prosthetist creating it and requires individualisation based on the size and shape. There is no standard measurement system used to aid prosthetic socket creation despite the severe impacts on physical health and quality of life if one is ill fitting. Pressure sensors embedded in a prosthetic socket were used to collect data at the socket–residuum interface. To choose an interpolation method, the sensor array was simplified to a 2D grid with a border for extrapolation and tested using previously collected walking test pressure data. Four multivariable interpolation methods were evaluated to create a colour map of the pressure data. Radial basis function interpolation was chosen, as it produced a clear image with a graduated interpolation between data points, and was used to create a colour map across the surface of a 3D prosthetic socket model. For the model to be accessible to clinical audiences, a desktop application was created using PyQt to view the model. The application allowed for connection to the sensors via Bluetooth, with the pressure data updating on the 3D model in real time. Clinician feedback on the application showed the potential for a clinical product; however, further development informed by feedback from rehabilitation clinicians and prosthesis users is required.