Transtibial Socket Design, Interface, and Suspension: A Clinical Practice Guideline

Prosthetic Componentry in Lower Limb Prosthetic Restoration

This article describes fundamental lower limb prosthesis concepts and componentry, including skeletal structure (endoskeletal vs exoskeletal), transtibial and transfemoral sockets, prosthetic suspension and interfaces, prosthetic knees, and prosthetic foot and ankle systems.

Insights into the spectrum of transtibial prosthetic socket design from expert clinicians and their digital records

Background

Transtibial prosthetic sockets are often grouped into patella tendon bearing (PTB) or total surface bearing (TSB) designs, but many variations in rectifications are used to apply these principles to an individual's personalised socket. Prosthetists currently have little objective evidence to assist them as they make design choices.

Aims

To compare rectifications made by experienced prosthetists across a range of patient demographics and limb shapes to improve understanding of socket design strategies.

Methodology

163 residual limb surface scans and corresponding CAD/CAM sockets were analysed for 134 randomly selected individuals in a UK prosthetics service. This included 142 PTB and 21 TSB designs. The limb and socket scans were compared to determine the location and size of rectifications. Rectifications were compiled for PTB and TSB designs, and associations between different rectification sizes were assessed using a variety of methods including linear regression, kernel density estimation (KDE) and a Naïve Bayes (NB) classification.

Results

Differences in design features were apparent between PTB and TSB sockets, notably for paratibial carves, gross volume reduction and distal end elongation. However, socket designs varied across a spectrum, with most showing a hybrid of the PTB and TSB principles. Pairwise correlations were observed between the size of some rectifications (e.g., paratibial carves; fibular head build and gross volume reduction). Conversely, the patellar tendon carve depth was not associated significantly with any other rectification, indicating its relative design insensitivity. The Naïve Bayes classifier produced design patterns consistent with expert clinician practice. For example, subtle local rectifications were associated with a large volume reduction (i.e., a TSB-like design), whereas more substantial local rectifications (i.e., a PTB-like design) were associated with a low volume reduction.

Clinical implications

This study demonstrates how we might learn from design records to support education and enhance evidence-based socket design. The method could be used to predict design features for newly presenting patients, based on categorisations of their limb shape and other demographics, implemented alongside expert clinical judgement as smart CAD/CAM design templates.

A pneumatic reconfigurable socket for transtibial amputees

Many transtibial amputees rate the fit between their residual limb and prosthetic socket as the most critical factor in satisfaction with using their prosthesis. This study aims to address the issue of prosthetic socket fit by reconfiguring the socket shape at the interface of the residual limb and socket. The proposed reconfigurable socket shifts pressure from sensitive areas and compensates for residual limb volume fluctuations, the most important factors in determining a good socket fit. Computed tomography scan images are employed to create the phantom limb of an amputee and to manufacture the reconfigurable socket. The performance of the reconfigurable socket was evaluated both experimentally and numerically using finite element modelling. The study showed that the reconfigurable socket can reduce interface pressure at targeted areas by up to 61%.

Mapping lines of non-extension in persons with lower limb amputation to aid comfort-driven prosthetic socket design

OBJECTIVE

This study aimed to develop a new technique to map the strain field for persons with lower-limb amputations to use for the design of comfortable prostheses.

METHODS

Using a DSLR camera with stenciled 2D markers, we demonstrated a technique to measure skin strain around the residual limb of persons with lower limb amputations. We used open-source software programs to reconstruct a series of cloud points derived from the pictures of the marked residual limb into 3D models, then calculated the minimum, maximum, and non-extension lines from directional strain fields.

RESULTS

A DSLR camera was successful in capturing 2D markers. The maximum mean principal strain was 68% ± 14%, observed around the patella. The minimum compressive mean principal strain of -31% ± 4% was observed posteriorly in the popliteal region of the knee. Although lines of non-extension (LoNE) appear separate in different participants, they are anatomically located in regions that could be generalized for the design of prostheses.

CONCLUSIONS

Marker locations extracted from the video of different poses can be compared to calculate strains from which the position of LoNE can be generated. The use of LoNE could be valuable in reducing discomfort at the socket interface and informing future socket design.

The association of the localized pain sensitivity in the residual limb and prosthesis use in male veterans with transtibial amputation

The association of localized pain sensitivity in the residual limb and prosthesis use has clinical implications, however, rarely been assessed. This study aimed to investigate pain sensitivity and explore its range, variability, and association with prosthesis use alongside other demographic and clinical characteristics of veterans with transtibial amputation. Pain sensitivity was determined as pressure pain threshold (PPT) and pressure tolerance (PT) in 19 male veterans with a mean age of 49.5 years using pressure algometry at 12 anatomical locations on‎ the residual limb. A comparison of pain sensitivity at each location, and among anatomical locations and participants was explored using independent t-test, analysis of variance, and Kruskal-Wallis tests, respectively. Pain sensitivity range (PSR), the difference between PT and PPT, was significantly different (p < 0.05) at mid-patellar tendon, medial tibial flare, and the distal end of the tibia. The lowest PPT and PT (20.5 and 33 Ncm-2, p = 0.13) were recorded at the distal end of the residual limb, and the highest PPT and PT (73.4 and 94.3 Ncm-2, p = 0.03) were recorded at the mid-patellar tendon. Pain sensitivity was significantly different among anatomical locations and participants. The correlation tests (Pearson and partial eta squared) showed non-significant associations of pain sensitivity with participants' demographic and clinical characteristics except for daily prosthesis use. The mid-patellar tendon, medial tibial flare, and distal end of the tibia revealed the lowest pain hypersensitivity ‎due to higher PSR. Longer daily prosthesis use was associated with increased pain sensitivity.

Validation of a Custom Interface Pressure Measurement System to Improve Fitting of Transtibial Prosthetic Check Sockets

Achievement of fit between the residual limb and prosthetic socket during socket manufacture is a priority for clinicians and is essential for safety. Clinicians have recognised the potential benefits of having a sensor system that can provide objective socket-limb interface pressure measurements during socket fitting, but the cost of existing systems makes current technology prohibitive. This study will report on the characterisation, validation and preliminary clinical implementation of a low cost, portable, wireless sensor system designed for use during socket manufacture. Characterisation and benchtop testing demonstrated acceptable accuracy, behaviour at variable temperature, and dynamic response for use in prosthetic socket applications. Our sensor system was validated with simultaneous measurement by a commercial sensor system in the sockets of three transtibial prosthesis users during a fitting session in the clinic. There were no statistically significant differences between the sensor system and the commercial sensor for a variety of functional activities. The sensor system was found to be valid in this clinical context. Future work should explore how pressure data relates to ratings of fit and comfort, and how objective pressure data might be used to assist in clinical decision making.

Transtibial prosthetic socket fitting: Australian prosthetist perspectives on primary challenges, management strategies, and opportunities for workflow and technological innovation

BACKGROUND

Following transtibial amputation, a custom-built socket is the most common interface between the prosthesis and residual limb. Desire from both prosthetists and prosthesis users for improved socket fitting processes have been well documented. However, there is currently limited information available about prosthetists' experiences of how prosthetic manufacturing workflow can contribute to socket fit problems.

OBJECTIVES

This study aims to determine how socket fit problems are currently detected and managed by prosthetists and to identify challenges, management strategies, and opportunities for workflow and technological innovation during prosthesis manufacture and socket fitting.

STUDY DESIGN

Mixed-method (quantitative and qualitative) survey.

METHODS

An online survey was developed and piloted in consultation with members of the Australian Orthotic Prosthetic Association. The final 25-question survey was distributed through their membership database. Mixed methods were used to analyze survey items. Qualitative items were grouped and coded under themes relating to challenges, management strategies, and opportunities. Quantitative data were analyzed using nonparametric descriptive methods.

RESULTS

Twenty-three respondents with a range of experience completed the survey. Seven of eight major Australian states/territories were represented. Primary workflow stages presenting challenges with limited strategies/solutions available to the prosthetists were roll-on liner selection, mold or cast modifications, communication with the client, and check socket fitting. Suggested solutions included improved socket-limb interface monitoring technology.

CONCLUSIONS

This study provides the first insights into prosthetist-identified challenges and limitations at different stages of the socket workflow and presents a starting point for more targeted research into innovation that may assist in these processes.

Transfemoral interface considerations: A clinical consensus practice guideline

BACKGROUND

Although there have been a number of studies exploring the impact and efficacy of transfemoral prosthetic components such as knee and foot mechanisms, the empirical evidence surrounding transfemoral prosthetic interface considerations is limited. This constitutes a substantial void for practicing clinicians seeking to apply best practices for patients who use transfemoral prostheses. Recent years have seen increased production and availability of clinical practice guidelines germane to prosthetic rehabilitation. In those areas where empirical evidence is lacking, consensus clinical opinions may constitute the highest level of evidence.

OBJECTIVE

A consensus exercise was performed to generate clinical practice recommendations in the areas of transfemoral interface considerations including socket variations and critical design features, suspension and interface considerations, alignment, heat retention and dermatologic considerations, female considerations, surgical considerations, and both regulatory and ethical considerations related to osseointegration.

METHODS

This began with the generation of postulate items through systematic and narrative literature reviews. A Delphi consensus exercise was performed among clinical experts in government hospital and private clinical practice settings, culminating in a series of clinical practice recommendations associated with the prosthesis-limb interface for individuals with transfemoral amputation.

RESULTS

The completed recommendations include guidance statements relative to socket variations and critical design features, female considerations, suspension and interface considerations, surgical variations and prescription considerations, rehabilitation team considerations and both regulatory and ethical considerations related to osseointegration.

CONCLUSIONS

The Delphi process facilitated the development of practice guidelines for transfemoral prosthetic interface considerations based on aggregated subject matter expertise.

Determining educational assessment criteria for patellar-tendon-bearing impressions for transtibial prosthetic sockets: A Delphi study

BACKGROUND

Validated criteria to guide assessment of student performance in clinical tasks in prosthetics and orthotics education have not been established. Lack of established criteria and assessment methods presents challenges in evaluating student performance on clinical tasks, such as taking impressions for patellar-tendon-bearing (PTB) sockets.

OBJECTIVES

To establish assessment criteria for the PTB impression process for use in educational settings.

STUDY DESIGN

Delphi consensus process.

METHODS

Initial Delphi survey items were based on interviews with prosthetic instructors and focus groups with prosthetic students. Expert prosthetic educators were then identified by purposive sampling to complete multiple-round Internet-based Delphi surveys. The Delphi surveys asked experts to indicate their level of agreement on various assessment methods and criteria in PTB education. Consensus for survey items was reviewed after each survey round and used to determine the content of and need for subsequent rounds.

RESULTS

Fourteen experts completed two Delphi survey rounds. Items were categorized into educational materials/strategies, impression stages/materials, measurement tools, measurements taken, assessment during impression, assessment after impression, feedback, student self-assessment, and grading. In two survey rounds, 40 items guiding assessment methods and criteria for PTB impressions achieved 80% consensus.

CONCLUSIONS

A high level of consensus was achieved in two survey rounds. Lower levels of consensus were reached on specific objective criteria, such as use of measurement thresholds when evaluating student impressions. Standardized assessment of student performance on PTB impression-taking instead relies primarily on qualitative assessments based on instructor expertise.

Limb Prostheses: Industry 1.0 to 4.0: Perspectives on Technological Advances in Prosthetic Care

Technological advances from Industry 1.0 to 4.0, have exercised an increasing influence on prosthetic technology and practices. This paper explores the historical development of the sector within the greater context of industrial revolution. Over the course of the first and up the midpoint of the second industrial revolutions, Industry 1.0 and 2.0, the production and provision of prosthetic devices was an ad hoc process performed by a range of craftspeople. Historical events and technological innovation in the mid-part of Industry 2.0 created an inflection point resulting in the emergence of prosthetists who concentrated solely on hand crafting and fitting artificial limbs as a professional specialty. The third industrial revolution, Industry 3.0, began transforming prosthetic devices themselves. Static or body powered devices began to incorporate digital technology and myoelectric control options and hand carved wood sockets transitioned to laminated designs. Industry 4.0 continued digital advancements and augmenting them with data bases which to which machine learning (M/L) could be applied. This made it possible to use modeling software to better design various elements of prosthetic componentry in conjunction with new materials, additive manufacturing processes and mass customization capabilities. Digitization also began supporting clinical practices, allowing the development of clinical evaluation tools which were becoming a necessity as those paying for devices began requiring objective evidence that the prosthetic technology being paid for was clinically and functionally appropriate and cost effective. Two additional disruptive dynamics emerged. The first was the use of social media tools, allowing amputees to connect directly with engineers and tech developers and become participants in the prosthetic design process. The second was innovation in medical treatments, from diabetes treatments having the potential to reduce the number of lower limb amputations to Osseointegration techniques, which allow for the direct attachment of a prosthesis to a bone anchored implant. Both have the potential to impact prosthetic clinical and business models. Questions remains as to how current prosthetic clinical practitioners will respond and adapt as Industry 4.0 as it continues to shape the sector.

The Impact of Limited Prosthetic Socket Documentation: A Researcher Perspective

The majority of limb prostheses are socket mounted. For these devices, the socket is essential for adequate prosthetic suspension, comfort, and control. The socket is unique among prosthetic components as it is not usually mass-produced and must instead be custom-made for individual residual limbs by a prosthetist. The knowledge of what constitutes "good" socket fit is gained by expert prosthetists and technicians over years of experience, and rarely documented. The reliance on tacit knowledge makes it difficult to standardize the criteria for a well-fitting socket, leading to difficulties understanding the impact of socket fit. Despite its importance, the workflow for socket fitting is often overlooked in literature. Due to the customized nature of sockets, if information is provided in literature, generally only the type of socket and suspension mechanism is noted, with information regarding the fitting and manufacturing processes omitted. In this article, the concerns, issues and consequences arising from lack of upper and lower limb socket documentation are discussed from a researcher perspective, supported by healthcare professionals and socket fabrication specialists. Key changes are proposed to the way socket manufacturing and evaluation are documented to assist future research.

Mechanical Pain Sensitivity in Postamputation Pain

OBJECTIVES

Postamputation, clinical markers of pain-related peripheral and central nervous system hypersensitivity remain understudied. This study aimed to identify whether adults with postamputation pain demonstrate greater pain sensitivity in primary (ie, amputated region) and secondary (ie, nonamputated region) sites, as compared with pain-free peers and controls with intact limbs.

METHODS

Ninety-four participants postunilateral, transtibial amputation (59 with pain, 35 pain-free) and 39 controls underwent pain-pressure threshold (PPT) testing at 10 sites. Pain-pressure thresholds were normalized to sex-specific control data using Z score conversions. Normalized primary-site and secondary-site PPTs were compared between groups using multivariate analysis of variance (P<0.050).

RESULTS

Compared with pain-free peers, adults with postamputation pain demonstrated reduced normalized PPTs across primary and secondary sites (mean difference=0.61-0.74, P=0.001 to 0.007). Compared with controls, adults with postamputation pain demonstrated reduced normalized PPTs (mean difference=0.52, P=0.026) only at primary sites.

DISCUSSION

Adults with postamputation pain demonstrate greater amputated region pain sensitivity as compared with pain-free peers or controls with intact limbs, indicating peripheral sensitization persists even after limb healing. Secondary-site pain sensitivity was similar between controls and adults with postamputation pain, suggesting central nervous system hypersensitivity may not be ubiquitous with postamputation pain. Studies are needed to investigate mechanisms underlying pain sensitivity differences between adults with and without postamputation pain.

Characterising Residual Limb Morphology and Prosthetic Socket Design Based on Expert Clinician Practice

Functional, comfortable prosthetic limbs depend on personalised sockets, currently designed using an iterative, expert-led process, which can be expensive and inconvenient. Computer-aided design and manufacturing (CAD/CAM) offers enhanced repeatability, but far more use could be made from clinicians’ extensive digital design records. Knowledge-based socket design using smart templates could collate successful design features and tailor them to a new patient. Based on 67 residual limb scans and corresponding sockets, this paper develops a method of objectively analysing personalised design approaches by expert prosthetists, using machine learning: principal component analysis (PCA) to extract key categories in anatomic and surgical variation, and k-means clustering to identify local ‘rectification’ design features. Rectification patterns representing Total Surface Bearing and Patella Tendon Bearing design philosophies are identified automatically by PCA, which reveals trends in socket design choice for different limb shapes that match clinical guidelines. Expert design practice is quantified by measuring the size of local rectifications identified by k-means clustering. Implementing smart templates based on these trends requires clinical assessment by prosthetists and does not substitute training. This study provides methods for population-based socket design analysis, and example data, which will support developments in CAD/CAM clinical practice and accuracy of biomechanics research.

Adjustable-Volume Prosthetic Sockets: Market Overview and Value Propositions

The prosthetic socket is commonly considered to be the most important part of the prosthesis and lack of fit can lead to skin breakdown, reduction in wear, reduction in activity, and consequential deleterious health effects. Furthermore, approximately 90% of amputations are due to a vascular etiology, which affect fluid retention regularity, and even small limb volume fluctuations can lead to lack of fit. Adjustability in the socket volume has been suggested as a potential solution to common fit issues but has lacked market penetration mostly due to lack of reimbursement. Despite this there are several adjustable-volume sockets emerging on the market today including prefabricated, modular, custom with adjustable-volume component, custom with adjustable-volume feature, and adjustable-hybrid sockets. Prefabricated sockets are mass produced in common sizes and fit directly to the patient by a prosthetist using pad kits, BOA dials, or straps. Modular sockets are assembled to a patient or model with panels or struts attached to an adjustable base. Custom sockets with adjustable-volume elements are traditionally-fabricated sockets made to a model of a patient's limb with a volume-adjustable component added or volume-adjustable feature built in. Custom-hybrid sockets are made custom to a model of the patient's limb and incorporate several aspects of the previous socket types and include some radically-unique design aspects which cannot be limited to one category. These adjustable-volume sockets offer several advantages to traditional rigid-volume sockets for the patient, prosthetist, and providing clinic. The micro-adjustability for the patient allows them to alter fit without removing the socket, maintaining a more intimate fit throughout the day than traditional sockets. The macro-adjustability for the prosthetist allows for increased options for fit customization including the ability to reverse or undo changes without necessarily re-making the socket. This allows for the most optimal fit for the patient. Adjustable volume also present efficiencies in the fitting process by simplifying or eliminating steps including residual limb shape capture, form modification, diagnostic fabrication, iterative alteration, and definitive fabrication with the different socket types affecting different steps. Due to these factors, adjustable-volume sockets have disrupted the market to the point where reimbursement reform is needed including additional L-codes in the United States and fee-for-service or fee-for-outcome associated with prosthetic follow-up care. Prosthetic care should also be separated from durable medical equipment to allow for alternative reimbursement models. As reimbursement adapts prosthetists must adapt correspondingly to differentiate their skillset from other allied health providers including incorporating more objective methods to show superior care outcomes. This adaptation should include a continued push for state and municipal licensure of prosthetists.

A Scoping Review of Pressure Measurements in Prosthetic Sockets of Transfemoral Amputees during Ambulation: Key Considerations for Sensor Design

Sensor systems to measure pressure at the stump-socket interface of transfemoral amputees are receiving increasing attention as they allow monitoring to evaluate patient comfort and socket fit. However, transfemoral amputees have many unique characteristics, and it is unclear whether existing research on sensor systems take these sufficiently into account or if it is conducted in ways likely to lead to substantial breakthroughs. This investigation addresses these concerns through a scoping review to profile research regarding sensors in transfemoral sockets with the aim of advancing and improving prosthetic socket design, comfort and fit for transfemoral amputees. Publications found from searching four scientific databases were screened, and 17 papers were found relating to the aim of this review. After quality assessment, 12 articles were finally selected for analysis. Three main contributions are provided: a de facto methodology for experimental studies on the implications of intra-socket pressure sensor use for transfemoral amputees; the suggestion that associated sensor design breakthroughs would be more likely if pressure sensors were developed in close combination with other types of sensors and in closer cooperation with those in possession of an in-depth domain knowledge in prosthetics; and that this research would be facilitated by increased interdisciplinary cooperation and open research data generation.

Self-reported socket comfort, mobility, and balance-confidence of individuals with transtibial amputation using pinlock vs suction suspension

BACKGROUND

Improper suspension between the residual limb and prosthesis can result in pistoning, which may compromise skin integrity and reduce overall user comfort. In addition to objective measures of limb pistoning, user perspective may provide insight into suspension system effectiveness.

OBJECTIVES

The primary objective of this analysis was to explore differences in self-reported measures among adults with transtibial amputation (TTA) using pinlock vs suction suspension systems.

STUDY DESIGN

This is a secondary analysis of cross-sectional data.

METHODS

Participants (n = 48) were included if they (1) were ≥18 years of age, (2) were community-dwelling, (3) had a unilateral TTA of ≥6 months, and (4) were prescribed a prosthesis with either pinlock or suction suspension. Participants completed self-reported measures evaluating socket comfort (Socket Comfort Score [SCS]), prosthesis-enabled mobility (Prosthesis Evaluation Questionnaire-Mobility Section [PEQ-MS]; Locomotor Capabilities Index [LCI]), and balance-confidence (Activities-Specific Balance Confidence Scale [ABC]).

RESULTS

Participants using suction suspension reported significantly higher SCS as compared with participants using pinlock suspension (P ≤ .001). No differences were observed between groups for PEQ-MS, LCI, and/or ABC.

CONCLUSIONS

Individuals with TTA using suction suspension may report greater socket comfort than peers using pinlock suspension, but prosthesis-enabled mobility and balance-confidence may be similar. Future research is warranted to confirm these preliminary findings using a prospective, crossover study design that controls for all suspected factors that might influence socket comfort.

Prosthetic management of unilateral transradial amputation and limb deficiency: Consensus clinical standards of care

INTRODUCTION

Upper limb research is currently lacking detailed clinical guidance on the provision of unilateral transradial prostheses. Clinical practice guidelines are meant to serve as assistance for the decision-making process, and Delphi surveys have been used with increasing frequency within orthotics and prosthetics to create these guidelines for clinical practice.

METHODS

A three round Delphi survey was used to gain consensus on clinical statements regarding unilateral transradial prostheses.

RESULTS

We achieved consensus (> 80% agreement) on a total of 40 statements by surveying 22 experts on upper limb prosthetics over three rounds of surveys. Response rate ranged from 81.8-86.4% with a total of 55 total statements under consideration throughout the duration of the survey. The 40 passing statements were arranged into nine guidelines for provision of prosthetic care in this population.

CONCLUSIONS

The Delphi technique allowed for the creation of a set of clinical practice guidelines for the unilateral transradial patient in the absence of conclusive empirical evidence.

Lower limb prosthetic interfaces: Clinical and technological advancement and potential future direction

The human-prosthesis interface is one of the most complicated challenges facing the field of prosthetics, despite substantive investments in research and development by researchers and clinicians around the world. The journal of the International Society for Prosthetics and Orthotics, Prosthetics and Orthotics International, has contributed substantively to the growing body of knowledge on this topic. In celebrating the 50th anniversary of the International Society for Prosthetics and Orthotics, this narrative review aims to explore how human-prosthesis interfaces have changed over the last five decades; how research has contributed to an understanding of interface mechanics; how clinical practice has been informed as a result; and what might be potential future directions. Studies reporting on comparison, design, manufacturing and evaluation of lower limb prosthetic sockets, and osseointegration were considered. This review demonstrates that, over the last 50 years, clinical research has improved our understanding of socket designs and their effects; however, high-quality research is still needed. In particular, there have been advances in the development of volume and thermal control mechanisms with a few designs having the potential for clinical application. Similarly, advances in sensing technology, soft tissue quantification techniques, computing technology, and additive manufacturing are moving towards enabling automated, data-driven manufacturing of sockets. In people who are unable to use a prosthetic socket, osseointegration provides a functional solution not available 50 years ago. Furthermore, osseointegration has the potential to facilitate neuromuscular integration. Despite these advances, further improvement in mechanical features of implants, and infection control and prevention are needed.

New Design Procedure of Transtibial ProsthesisBed Stump Using Topological Optimization Method

This paper presents a new design procedure for production of a transtibial prosthesis bed stump by three-dimensional (3D) printing with topological optimization. The suggested procedure combines the medical perspective with finite element analysis and facilitates regaining the symmetry in patients with transtibial prosthesis, which leads to life improvement. The particular focus of the study is the weight reduction of the lower part of the bed stump, while taking into account its stiffness and load-bearing capacity. The first part of the work deals with the analysis of the subject geometry of the bed stump, which is usually oversized in terms of the weight and stiffness that are necessary for the current application. In the second part, an analysis of walking biomechanics with a focus on the impact and rebound phases is presented. Based on the obtained information, a spatial model of the lower part of the bed stump is proposed in the third phase, in which the finite element method is described. In the fourth part, the topological optimization method is used for reducing the structure weight. In the last part, the results of the designed model are analyzed. Finally, the recommendations for the settings of the method are presented. The work is based on the practical industry requirements, and the obtained results will be reflected in the design of new types of transtibial prosthesis.

Reported physical activity and quality of life in people with lower limb amputation using two types of prosthetic suspension systems

BACKGROUND

Vacuum-assisted suspension systems provide better suspension than non-vacuum systems, but data are limited on whether they improve physical activity levels and quality of life for people with amputation.

OBJECTIVES

To compare the physical activity and quality of life levels of people with transtibial amputation using PIN/LOCK suspension system or vacuum-assisted suspension systems with those of able-bodied controls and to investigate parameters associated with physical activity levels.

STUDY DESIGN

A cross-sectional observational study.

METHODS

Fifty-one people with amputation and 51 controls participated. The International Physical Activity Questionnaire Short Form and Short Form 36 were used to measure the physical activity and quality of life, respectively.

RESULTS

The total physical activity and Short Form 36 scores were significantly lower in the participants with amputation than the controls. There were no significant differences between the two types of suspension systems in terms of physical activity levels and quality of life. The vacuum-assisted suspension system users reported significantly more bodily pain on the Short Form 36 questionnaire than the controls (p = 0.003). The only parameter that correlated significantly with the total physical activity was the Short Form 36 physical functioning subscale (r = 0.302, p = 0.031).

CONCLUSION

Contrary to our expectations, vacuum-assisted suspension system users compared to PIN/LOCK users did not report greater levels of physical activity or improved quality of life or levels closer to comparable controls.

CLINICAL RELEVANCE

A better understanding of the effects of different prosthetic suspension systems on physical activity and quality of life may help clinicians when prescribing prostheses, as well as setting appropriate prosthetic expectations. This study suggests that vacuum-assisted suspension systems and PIN/LOCK suspension systems provide equal benefit to users with regards to physical activity and quality of life.