Socket Fit Research Articles

Osseointegration of the Tibia After a Primary Amputation

Background: Transtibial amputation (TTA) reconstruction via press-fit osseointegration permits direct skeletal connection between a patient’s residual limb and the prosthetic leg. Osseointegration reconstruction has predominantly been utilized in transfemoral amputation (TFA), resulting in overwhelmingly positive functional and quality-of-life improvements compared with traditional socket prostheses 1–3 . The adoption of this technology has been slower in TTA, likely because patients undergoing TTA have superior mobility compared with those undergoing TFA, leading some clinicians to believe that their mobility cannot be further improved. However, patients undergoing TTA are still plagued by a degree of socket-related issues and decreased quality of life that is similar to those undergoing TFA 4 . With the safety of osseointegration demonstrated in the literature 5–7 and the high prevalence of TTAs in the general population 8 , it is important that osseointegration be utilized in the rehabilitation and reconstruction offered to patients undergoing TTA. Description: Planning starts with anteroposterior and lateral radiographs as well as computed tomography to optimally size the implant. The surgical procedure begins with exposure of the residual tibia, revising the bone cut if needed, and taking routine deep cultures. Reaming is performed over a centrally placed intramedullary guidewire, followed by sequential broaching up to the implant size under fluoroscopic guidance. The implant is then impacted into place. The muscles are closed in a purse-string fashion, followed by skin closure and the creation of a stoma. The external components are then attached to the implant. Alternatives: Traditional prostheses are attached to the residual limb via suction sockets. Patients who have undergone an amputation and are dissatisfied with the resulting quality of life or mobility can undergo attempted modification of their socket or liner components by a prosthetist. Alternatively, these patients can modify or limit their activities and forgo prosthetic limb support entirely. Other surgical options that may improve socket fit include revision amputation, residual bone lengthening, or soft-tissue contouring. Additional osseointegration implant designs also exist 9 . Rationale: Suction sockets are known to cause multiple issues for patients who have undergone an amputation, including skin ulceration, sweating, poor fit, residual limb pain, physical disability, and impaired quality of life 10,11 . TTA patients can be affected as substantially as TFA patients 4,12 . The poor functionality of the socket is exacerbated in patients whose residual soft-tissue envelope is either in excess or fails to provide proper cushioning against the circumferential squeezing of a socket. Osseointegration bypasses these issues by linking patient and prosthesis via direct skeletal connection. Of the different design options available, press-fit osseointegration is the most commonly utilized and simplifies the implantation process into a single stage, in contrast with alternative 2-stage designs 9 . Press-fit osseointegration has been successfully performed in patients having had an amputation for a variety of etiologies 13–15 . Expected Outcomes: Outcome studies consistently showed improvements in patient physical function, prosthesis wear time, overall satisfaction, and quality of life following conversion to osseointegration from traditional socket prostheses 5,16 . We recently reported on 31 consecutive osseointegration patients (13 TTA and 18 TFA) with a follow-up of 18 months 15 . Overall and functional outcome domains of the Patient-Reported Outcomes Measurement Information System (PROMIS) and Questionnaire for Persons with a Transfemoral Amputation (Q-TFA) improved significantly, as did performance on physical function tests. The most common complications following prosthetic osseointegration—which have been better documented in studies of femoral osseointegration—are superficial soft-tissue infections responsive to oral antibiotics 15,17 and, much less commonly, periprosthetic fractures that are treatable with implant retention and standard internal-fixation techniques 18 . Important Tips: Template an implant that matches the inner diameter of the diaphyseal bone.Do not cement press-fit osseointegration implants for any reason 19 .In cases of a short residuum with a greater proportion of proximal tibial metaphyseal bone, favor broaching after under-reaming to impact cancellous bone.Distal stress fractures with implantation do not typically affect implant stability.Perform tight, circumferential muscle closure around the bone-implant interface with absorbable sutures, creating a biologic purse string.Excise excess subscarpal fat and skin from the anterior and/or posterior flaps prior to closure 20 .Graduated, partial weightbearing typically begins around week 4 and progresses to full weightbearing by week 10 to 12. Acronyms & Abbreviations: LLD = limb length discrepancyCT = computed tomographyTMR = targeted muscle reinnervationOI = osseointegrationMRI = magnetic resonance imagingAP = anteroposteriorEQ-5D = EuroQol 5 DimensionsLD-SRS = Limb Deformity – Scoliosis Research SocietyI&D = irrigation and debridement

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

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. 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. Mixed-method (quantitative and qualitative) survey. 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. 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. 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.

Why Does My Prosthetic Hand Not Always Do What It Is Told?

There are online videos that appear to show electrically powered prosthetic (artificial) hands to be near-perfect replacements for a missing hand. However, for many users, the reality can be quite different. Prosthetic hands do not always respond as expected, which can be frustrating. A prosthetic hand is controlled by muscle signals in the remaining part of the person’s affected arm, using sensors called electrodes. The electrodes are embedded within the socket, which is the part of the prosthetic arm that connects it to the person’s arm. When they activate their muscles, the hand can open, close, or change its grip. If the socket moves, it can pull the electrodes away from the skin. As a result, the muscle activity signaling the person’s intention cannot be properly detected, and the hand will not work very well. In this article, we explain why socket fit may be the most important part of a prosthetic arm.

Pressure Reduction Management System in Three-Dimensional-Printed Transtibial Prosthetic Socket during Stance Phase

ABSTRACT Introduction High pressure on sensitive areas of the residual limb while wearing a prosthetic socket must be minimized to avoid injury and uncomfortable fitting. The purpose of this study was to reduce the peak pressures on sensitive regions within a three-dimensional (3D)-printed transtibial prosthetic socket. Materials and Methods This study proposed a 3D-printed socket with three built-in tiny air bladders integrated within the interface between the liner and socket and electronically managed by a pressure and volume control system. A pseudo-artificial residual limb was fabricated to mimic the transtibial residual limb. The interface pressure in the 3D-printed socket was evaluated using F-socket transducers during inflation and deflation of the air bladders in the stance phase through universal tensile machine load. Results Based on the statistical analysis, the highest significant pressure reduction (P < 0.05) was 5.71%, which was recorded at the posterior region, and 4.68% (P < 0.05) at the medial region during posterior and medial air bladders inflation, respectively. Conclusion Peak pressures were reduced at the lateral tibia condyle, tibia tuberosity, tibia crest, anterior distal end of tibia, fibula head, distal end of fibula, medial femoral condyle, lateral femur condyle, and patellar of the artificial residual limb. Clinical Relevance This system has the potential to minimize high pressures at the subregions of the residual limb in clinical settings and in day-to-day activities. Thus, this design could provide an excellent pressure and volume control at the bony areas, which improves satisfaction and socket fit for persons with amputation.

Design of Adjustable Frame-Type Prosthetic Socket for Lower Limb

ObjectivesProsthetic socket is the contact interface between the stump and the prosthesis, and also the interface component that transmits forces from the stump to the prosthesis distal. The current prosthetic socket fit is a major factor affecting rehabilitation, especially with the stump volume fluctuations. The main goal of this article is to design an adjustable frame-type prosthetic socket with constant force to adapt to the stump volume fluctuations. Materials and methodsIn this paper, an adjustable frame-type prosthetic socket with constant force is designed. The constant force device is designed based on the superelasticity of the shape memory alloy for maintaining constant stump-socket interface stress and automatically adapting to certain volume fluctuations. The constant force extrusion performance of this prosthetic socket was verified and optimized by finite element analysis. ResultsThe results suggest that the constant force unit may maintain constant interface stress. According to the optimization results, the shape memory alloy dimensional parameters could be selected according to different requirements. ConclusionThe adjustable frame-type prosthetic socket allows the user to adjust the socket volume through the cable system and has a large heat dissipation area. The constant force unit maintains constant interface stress and automatically adapts to stump volume fluctuations.

Analysis of lower limb prosthetic socket interface based on stress and motion measurements.

The study was designed to establish a biomechanical assessment platform for the lower limb residuum/socket interface as a function of duration and speed of movement. The approach exploits an interface sensor which measures multi-directional stresses at the interface. The corresponding interface coupling motion was assessed using a 3D motion capture system. A longitudinal study, involving a trans-femoral amputee, was conducted with nine repeated level walking sessions over a 12-month period. The effect of walking speed on interface biomechanics was also assessed. Interface peak pressures and shear stresses in the range of 55–59 kPa and 12–19 kPa were measured, respectively, over all sessions in the 12 months study period at the posterior-proximal location of the residuum. The peak pressure and longitudinal shear values were found to fluctuate approximately 11% and 40% as against its maximum value, respectively, over 12 months. In addition, up to 12° of angular coupling and up to 28 mm of pistoning were recorded over a gait cycle, which was found to change by 29% and 45% respectively over the study period. The variation in walking speed, by altering self-selected cadence, resulted in changes of pressure and shear stresses at mid-stance of the gait cycle. In particular, as compared with self-selected cadence, for fast speed, peak pressure and peak longitudinal shear stress decreased by 5% and 33%, respectively. For slow speed, peak pressure and peak longitudinal shear stress increased by 7% and 17%, respectively. The corresponding angular and pistoning revealed a variation of up to 29% and 45%, respectively. This biomechanical assessment approach shows promise in the quantitative assessment of interface kinematics and kinetics for lower limb prosthetics, the usage of which could assist the clinical assessment of prosthetic socket fit.

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 Rehabilitation Ensuring 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.

Finite element analysis of the stump-ischial containment socket interaction: a technical note.

The role of the above-knee socket is to ensure the load transfer via the coupling of residual limb-prosthesis with minimal discomfort and without damaging the soft tissues. Modelling is a potential tool to predict socket fit prior to manufacture. However, state-of-the-art models only include the femur in soft tissues submitted to static loads neglecting the contribution of the hip joint. The hip joint is particularly challenging to model because it requires to compute the forces of muscles inserting on the residual limb. This work proposes a modelling of the hip joint including the estimation of muscular forces using a combined MusculoSKeletal (MSK)/Finite Element (FE) framework. An experimental-numerical approach was conducted on one femoral amputee subject. This allowed to i) model the hip joint and personalise muscular forces, ii) study the impact of the ischial support, and iii) evaluate the interface pressure. A reduction of the gluteus medius force from the MSK modelling was noticed when considering the ischial support. Interface pressure, predicted between 63 to 71 kPa, agreed with experimental literature data. The contribution of the hip joint is a key element of the modelling approach for the prediction of the socket interface pressure with the residual limb soft tissues.

A Multi-User Transradial Functional-Test Socket for Validation of New Myoelectric Prosthetic Control Strategies.

The validation of myoelectric prosthetic control strategies for individuals experiencing upper-limb loss is hindered by the time and cost affiliated with traditional custom-fabricated sockets. Consequently, researchers often rely upon virtual reality or robotic arms to validate novel control strategies, which limits end-user involvement. Prosthetists fabricate diagnostic check sockets to assess and refine socket fit, but these clinical techniques are not readily available to researchers and are not intended to assess functionality for control strategies. Here we present a multi-user, low-cost, transradial, functional-test socket for short-term research use that can be custom-fit and donned rapidly, used in conjunction with various electromyography configurations, and adapted for use with various residual limbs and terminal devices. In this study, participants with upper-limb amputation completed functional tasks in physical and virtual environments both with and without the socket, and they reported on their perceived comfort level over time. The functional-test socket was fabricated prior to participants' arrival, iteratively fitted by the researchers within 10 mins, and donned in under 1 min (excluding electrode placement, which will vary for different use cases). It accommodated multiple individuals and terminal devices and had a total cost of materials under $10 USD. Across all participants, the socket did not significantly impede functional task performance or reduce the electromyography signal-to-noise ratio. The socket was rated as comfortable enough for at least 2 h of use, though it was expectedly perceived as less comfortable than a clinically-prescribed daily-use socket. The development of this multi-user, transradial, functional-test socket constitutes an important step toward increased end-user participation in advanced myoelectric prosthetic research. The socket design has been open-sourced and is available for other researchers.

Activity, socket fit, comfort and community participation in lower limb prosthesis users: a Cambodian cohort study

BackgroundAfter amputation, many people become less active, feel lonely and lose independence. Understanding the factors associated with low physical activity levels and participation could contribute to defining key interventions which can support prosthesis users so they can live a more active and socially included lifestyle. This longitudinal observational study aims to assess relationships between physical activity, community participation, prosthetic fit, comfort and user satisfaction using actimetry, 3D scans and questionnaires in a Cambodian cohort of established lower limb prosthesis users.MethodsTwenty participants (5F:15M, nine transfemoral, eleven transtibial, 24–60 years old and 3–43 years since amputation) were recruited. They completed a questionnaire which included their demographics, community participation, prosthesis satisfaction and comfort at the start of the study, and between three and six months later. Their prosthetic sockets and residual limbs were 3D scanned at the start and end of the study. Accelerometers were embedded under the cosmesis on the shank of the prosthesis, to collect ten weeks of activity data.ResultsParticipants averaged 4470 steps/day (743–7315 steps/day), and wore their prosthesis for most waking hours, averaging 13.4 h/day (4.5–17.6 h/day). Self-reported measures of activity and hours of wear correlated with these accelerometer data (Spearman’s rho rs = 0.59, and rs = 0.71, respectively). Participants who were more active wore their prosthesis for more hours/day (Pearson r = 0.73) and were more satisfied with socket fit (rs = 0.49). A longer residual limb correlated with better community participation (rs = 0.56) and comfort (rs = 0.56). Self-reported community participation did not correlate with a person’s activity level (rs = 0.13), or their prosthesis comfort (rs = 0.19), and there was only weak correlation between how important the activity was to an individual, and how often they participated in it (rs = 0.37). A simple 0–10 scale of overall comfort did not provide enough detail to understand the types and severity of discomfort experienced.ConclusionAssociations between perceived and measured activity levels correlated with socket satisfaction in this cohort of people with established lower limb amputations. The small sample size means these correlations should be interpreted with caution, but they indicate variables worthy of further study to understand barriers to community engagement and physical activity for prosthesis users in Cambodia, and potentially in other settings.

A Prospective Assessment of an Adjustable, Immediate Fit, Subischial Transfemoral Prosthesis

ObjectiveTo assess the feasibility of an adjustable, subischial transfemoral prosthesis by comparing self-reported outcome measures regarding socket comfort, fit and utility relative to a persons’ conventionally made socket. Assessing limb compressibility was another aim of this study. DesignA single-group pre-post intervention design. SettingPhysical medicine and rehabilitation biomechanics laboratory. ParticipantsAll 18 enrolled participants (N = 18) completed the feasibility trial. There were 16 men and 2 women with an average age of 59.4 (±7) years. Most of the participants (61.1%) had worn a socket for 1 to 10 years before the trial, 22.2% of the participants had worn one for less than a year, and 16.7% of the participants had worn a prosthesis for more than 10 years. InterventionParticipants were fit with the study prosthesis and used it for a 2-week home trial. Main Outcome MeasuresA Prosthetic Comfort and Utility Questionnaire was completed on the participant's conventional prosthetic device and the subischial socket system after the trial. ResultsThe adjustable subischial prostheses were rated superior overall to the participant's conventional sockets (40.9 ± 7.2 vs 32.8 ± 10.8; P=.004). Six of the 10 parameters measured (adjustability, overall fit, prosthesis weight, sitting comfort, standing comfort, and standing stability) were rated higher for the adjustable prostheses compared to the conventional sockets. Compression of the soft tissues of the thigh ranged from 5.6 ± 4.2 cm at the distal end to 7.3 ± 3.6 cm at the proximal site. There were no falls, skin breakdown, or limb ischemia. At the 2-month telephone follow-up, 61% of subjects had transitioned to using the adjustable subischial socket most of the time. ConclusionsThe adjustable, immediate fit, subischial prosthesis provided safe, comfortable, and functional ambulation for persons with transfemoral limb loss in this short-term feasibility study. This study supports the consideration of a new paradigm in transfemoral prosthetics—adjustable subischial sockets. These devices should be tested in a larger multi-center study.

Air microfluidics-enabled soft robotic transtibial prosthesis socket liner toward dynamic management of residual limb contact pressure and volume fluctuation.

Residual limb volume fluctuation and the resulting contact pressures are some of the key factors leading to skin ulcerations, suboptimal prosthetic functioning, pain, and diminishing quality of life of transtibial amputees. Self-management of socket fit is complicated by peripheral neuropathy, reducing the perception of pressure and pain in the residual limb. We introduce a novel proof-of-concept for a transtibial prosthetic socket liner with the potential to dynamically adjust the fit between the limb and socket. The core of the technology is a small air microfluidic chip (10 cm3 and 10 g) with 10 on-chip valves that enable sequential pressurizing of 10 actuators in custom sizes to match the pressures required by the residual limb's unique anatomy. The microfluidic chip largely reduced the number of electromechanical solenoid valves needed for sequential control of 10 actuators (2 instead of 10 valves), resulting in the reduction of the required power, size, mass, and cost of the control box toward an affordable and wearable prosthetic socket. Proof-of-concept testing demonstrated that the applied pressures can be varied in the desired sequence and to redistribute pressure. Future work will focus on integrating the system with biofidelic prosthetic sockets and residual limb models to investigate the ability to redistribute pressure away from pressure-sensitive regions (e.g., fibular head) to pressure tolerant areas. Overall, the dynamic prosthesis socket liner is very encouraging for creating a dynamic socket fit system that can be seamlessly integrated with existing socket fabrication methods for managing residual limb volume fluctuations and contact pressure.

Redundancy Reduction for Sensor Deployment in Prosthetic Socket: A Case Study.

The irregular pressure exerted by a prosthetic socket over the residual limb is one of the major factors that cause the discomfort of amputees using artificial limbs. By deploying the wearable sensors inside the socket, the interfacial pressure distribution can be studied to find the active regions and rectify the socket design. In this case study, a clustering-based analysis method is presented to evaluate the density and layout of these sensors, which aims to reduce the local redundancy of the sensor deployment. In particular, a Self-Organizing Map (SOM) and K-means algorithm are employed to find the clustering results of the sensor data, taking the pressure measurement of a predefined sensor placement as the input. Then, one suitable clustering result is selected to detect the layout redundancy from the input area. After that, the Pearson correlation coefficient (PCC) is used as a similarity metric to guide the removal of redundant sensors and generate a new sparser layout. The Jenson–Shannon Divergence (JSD) and the mean pressure are applied as posterior validation metrics that compare the pressure features before and after sensor removal. A case study of a clinical trial with two sensor strips is used to prove the utility of the clustering-based analysis method. The sensors on the posterior and medial regions are suggested to be reduced, and the main pressure features are kept. The proposed method can help sensor designers optimize sensor configurations for intra-socket measurements and thus assist the prosthetists in improving the socket fitting.

Within-subject effects of standardized prosthetic socket modifications on physical function and patient-reported outcomes

BackgroundAmong 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.MethodsUsers 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).DiscussionKnowledge 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 registrationClinicalTrials.gov NCT05041998. Date of registration: Sept 13, 2021.

Revision Amputation with Press-Fit Osseointegration for Transfemoral Amputees.

We demonstrate the fundamentals of a single-stage procedure involving an impacted press-fit porous-coated titanium osseointegration implant. The preoperative evaluation is summarized and the specific surgical steps are described: exposure, osteotomy, canal preparation, implant insertion, (optional) targeted muscle reinnervation, muscle closure, soft-tissue contouring and stoma creation, and abutment insertion. Amputees who are dissatisfied with their quality of life or mobility when using a socket prosthesis can attempt to modify their socket or activity level or accept their situation. Non-osseointegration surgical options to try to improve socket fit include bone lengthening and/or soft-tissue contouring. An alternative design is a screw-type osseointegration implant1. Press-fit osseointegration can be provided for amputees having difficulty with socket wear5. Press-fit osseointegration usually provides superior mobility and quality of life compared with nonoperative and other operative options for patients expressing dissatisfaction for reasons such as those mentioned above, including poor fit, compromised energy transfer, skin pinching, compression, and abrasions. Review articles describing the clinical outcomes of osseointegration consistently suggest that patients have improved prosthesis wear time, mobility, and quality of life compared with patients with a socket prosthesis3,4. In a recent study2 of 18 femoral and 13 tibial amputees who had osseointegration, Reif et al. showed significant improvements in prosthesis wear time, mobility, and multiple quality-of-life surveys at a mean follow-up of nearly 2 years. The most common postoperative complication for this procedure is low-grade soft-tissue infection, which is usually managed by a short course of oral antibiotics. Much less often, soft-tissue debridement or implant removal may be needed to manage infection. Periprosthetic fractures can nearly always be managed with familiar fracture fixation techniques and implant retention6. Template and choose an implant with an optimal diameter that encroaches the inner cortex at the narrowest bone diameter; an implant that is too wide may not fit without causing a large fracture, and an implant that is too narrow may fall out. Do not cement the implant7.Ideally, the abutment of the implant should rest against a flat transverse bone end with cortical contact and leave the correct amount of room for the prosthetic knee so that it matches the height of the contralateral knee; avoid inserting an implant too distally or in too wide a metaphyseal flare.Gentle impaction pressure is necessary and small contained distal fractures are acceptable, but avoid causing a propagating fracture. Do not place cerclage cables or loose bone graft at these small fracture sites.Avoid the use of a tourniquet during intramedullary reaming to prevent potential heat-induced osteonecrosis.Nerve surgery such as targeted muscle reinnervation, if indicated, can be performed in the same surgical episode as the osseointegration.The muscles should be closed at the bone-implant interface with use of a tight purse string in order to provide a vascularized tissue barrier against bacterial ingress8.The skin surrounding the stoma should have unnecessary fat removed, but not excess removal leading to skin necrosis. The skin fascia should be sutured to the muscle surrounding the stoma to stabilize the peri-stomal skin.Soft-tissue contouring is needed to achieve the optimal soft-tissue tension around the stoma and abutment. Single-stage surgery has a distinct advantage in this regard. MVA = motor vehicle accidentAP = anteroposteriorCT = computed tomographyTMR = targeted muscle reinnervationQTFA = Questionnaire for Persons with a Transfemoral AmputationEQ-5D = EuroQol 5 DimensionsLD-SRS = Limb Deformity-Scoliosis Research Society (questionnaire)PROMIS = Patient-Reported Outcomes Measurement Information System.

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.

Evaluation of the new, patient-adjustable socket system Varos in the early phase of prosthetic rehabilitation: a pilot study.

Current prosthetic sockets often provide limited anatomical fit, especially in patients with residual limb volume changes and fluctuations. To address these issues, Ottobock has developed the Varos Socket, a modular socket that can be adjusted by the user. The aim of this study was to evaluate the potential benefits and acceptance of a newly designed patient-adjustable socket in transfemoral amputees in early phase of prosthetic rehabilitation. A prospective A-B-A pilot study was conducted. The setting of the study was an Orthopedic Rehabilitation Clinic. Ten patients with unilateral transfemoral amputation and recent amputation. All patients underwent a standard rehabilitation program with physical therapy. The outcome measures included the Comprehensive Lower-limb Amputee Socket Survey (CLASS), Score Comfort Scale (SCS), a Socket Fit Scale, frequency of falls and stumbles, perceived pain, and satisfaction. The total CLASS score and three sub-scores (i.e., stability, suspension, comfort) were significantly higher with Varos socket. Significantly improved comfort and quality of socket fit were observed as measured by the Socket-Comfort-Scale and Socket-Fit-Scale and a trend towards reduced residual limb pain. 87.5% of the patients reported higher satisfaction than with the standard socket. The results suggest that the Varos socket improved comfort, stability, suspension, appearance, pain, and satisfaction in transfemoral amputees during the early rehabilitation program. A larger study and a longer observation period are warranted to confirm the results of this study. Quick and easy socket fitting as well as instant adjustability by the patient bear substantial potential to improve and accelerate the rehabilitation process in the early phase after amputation.

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.

Scoping review to evaluate existing measurement parameters and clinical outcomes of transtibial prosthetic alignment and socket fit.

Fit and alignment are observable objectives of the prosthesis rendering process for individuals with lower limb amputation. Nevertheless, there is a dearth of validated measures to directly assess the quality of this clinical procedure. The objectives of this scoping review are to evaluate existing measurement parameters and clinical outcomes used in investigations of transtibial socket fit or prosthetic alignment and to identify gaps in the literature regarding tools for evaluation of prosthetic fitting. Scoping literature review. A comprehensive search was conducted in the following databases: MEDLINE (through PubMed), Embase (through Elsevier), Scopus (through Elsevier), and Engineering Village (through Elsevier), resulting in 6107 studies to be screened. Sixty-three studies were included in the review. When measuring fit, studies most frequently reported on patient-reported comfort (n = 22) and socket size compared with the residual limb volume (n = 9). Alignment was most frequently measured by the prosthetists' judgment and/or use of an alignment jig (n = 34). The measurement parameters used to determine alignment or fit varied greatly among the included studies. This review demonstrated that most measures of socket fit rely on a patient's self-report and may vary with biopsychosocial factors unrelated to the socket fitting process. Meanwhile, alignment is determined mostly by the prosthetist's judgment, paired with objective measurements, such as alignment jigs and gait analysis. Efforts to standardize and validate measures of these parameters of prosthetic fitting are vital to improving clinical practice and reporting outcomes.

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.