Subischial vs. Ischial Containment Sockets: A Multicenter Randomized Crossover Trial to Assess Comfort and Mobility in Daily Life Situations

Background:Current transfemoral prosthetic sockets are problematic as they restrict function, lack comfort, and cause residual limb problems. Development of a subischial socket with lower proximal trim lines is an appealing way to address this problem and may contribute to improving quality of life of persons with transfemoral amputation.Objectives:The purpose of this study was to illustrate the use of a new subischial socket in two subjects.Study design:Case series.Methods:Two unilateral transfemoral prosthesis users participated in preliminary socket evaluations comparing functional performance of the new subischial socket to ischial containment sockets. Testing included gait analysis, socket comfort score, and performance-based clinical outcome measures (Rapid-Sit-To-Stand, Four-Square-Step-Test, and Agility T-Test).Results:For both subjects, comfort was better in the subischial socket, while gait and clinical outcomes were generally comparable between sockets.Conclusion:While these evaluations are promising regarding the ability to function in this new socket design, more definitive evaluation is needed.Clinical relevanceUsing gait analysis, socket comfort score and performance-based outcome measures, use of the Northwestern University Flexible Subischial Vaccum Socket was evaluated in two transfemoral prosthesis users. Socket comfort improved for both subjects with comparable function compared to ischial containment sockets.

Comparison of Ischial Containment and Subischial Sockets on Comfort, Function, Quality of Life, and Satisfaction With Device in Persons With Unilateral Transfemoral Amputation: A Randomized Crossover Trial

Little research describes which transfemoral socket design features are important for coronal plane stability, socket comfort, and gait. Our study objectives were to (1) relate socket comfort during gait to a rank order of changes in ischial containment (IC) and tissue loading and (2) compare socket comfort during gait when tissue loading and IC were systematically manipulated. Six randomly assigned socket conditions (IC and tissue compression) were assessed: (1) IC and high, (2) IC and medium, (3) IC and low, (4) no IC and high, (5) no IC and medium, and (6) no IC and low. For the six subjects in this study, there was a strong, negative relationship between comfort and changes in IC and tissue loading (rho = -0.89). With the ischium contained, tissue loading did not influence socket comfort (p = 0.47). With no IC, the socket was equally comfortable with high tissue loading (p = 0.36) but the medium (p = 0.04) and low (p = 0.02) tissue loading conditions decreased comfort significantly. Coronal plane hip moments, lateral trunk lean, step width, and walking speed were invariant to changes in IC and/or tissue loading. Our results suggest that in an IC socket, medial tissue loading mattered little in terms of comfort. Sockets without IC required high tissue loading to be as comfortable as those with IC, while suboptimal tissue loading compromised comfort.

Introduction This study investigates the relationships among mobility, pain, and socket comfort for people with lower-limb amputations who use prostheses over specific treatment milestones. Methods This is a retrospective chart analysis from January 1, 2015, to July 15, 2021. Outcome measures included are the Socket Comfort Score, Pain Scale, 2-Minute Walk Test, and PLUS-M (Prosthetic Limb Users Survey of Mobility). Data were collected at 4 milestones: Baseline and Discharge from Rehabilitation for those receiving their first prosthesis in rehabilitation and Initial Evaluation and Definitive Fitting for experienced prosthesis users receiving a replacement socket. Demographic data were analyzed using descriptive statistics, and the strength of the correlations was determined using Pearson’s correlations. Results Measures were included from 59 individuals in rehabilitation and 165 individuals receiving a replacement socket. The sample was in general older males with transtibial amputations due to a variety of etiologies. The Pain Scale was negatively correlated with the Socket Comfort Score (−0.49 < r < −0.60), and the PLUS-M was correlated with the 2-minute walk test (0.41 < r < 0.61) at all milestones. Additionally, there were positive correlations between the PLUS-M and Socket Comfort Score (0.30 < r < 0.32), and negative correlations between the PLUS-M and Pain Scale (−0.46 < r < −0.32) for those receiving a replacement socket. Conclusions The relationship among comfort, pain, and mobility changes over the treatment timeline. There is evidence that, by addressing comfort and pain for those with experience using a prosthesis, clinicians can support the goal of increasing self-reported functional mobility. Clinical Relevance This study provides novel information about the relationships among pain, comfort, and mobility and the importance of considering the impact of treatment milestones when taking outcome measures and providing interpretative values as scores and relationships differ over the course of treatment.

P 036 - Pressure mapping analysis for forward and backward gait

Objective To determine if socket comfort predicts walking capacity, walking performance, and life-space mobility. Design Observational exploratory study involving a secondary cross-sectional analysis using multiple regression of data collected from an exercise intervention trial. Setting Laboratory setting for clinical assessments; community setting for walking performance. Participants Community-dwelling lower-limb prosthesis users over 50 years old (n = 72). Main measures Socket Comfort Score, 2-Minute Walk Test, step count, Life Space Assessment, and control variables including demographics, Short Physical Performance Battery, Four Square Step Test, and Walking While Talking. Results Regression modeling showed Socket Comfort Score as a statistically significant predictor of 2-Minute Walk Test (B = 6.9 m, 95% CI [2.7, 11.1] m) alongside amputation level, Walking While Talking test, and Short Physical Performance Battery (greatest contribution to the model); the model accounted for 61% of the variance. Socket Comfort Score was not a statistically significant predictor of step count. Socket Comfort Score was the only statistically significant predictor of Life Space Assessment (B = 4.9, 95% CI [1.1, 8.8]); the model accounted for 12% of the variance. Conclusions Socket comfort played a notable role in predicting walking capacity and life space mobility, but not in walking performance. Improving lower extremity function may have greater impact on walking overall. While this study provides context regarding socket comfort that clinicians may consider when planning holistic prosthetic rehabilitation, mixed findings in the literature suggest that further research on how socket comfort relates to walking outcomes in the community is warranted.

Achieving optimal fitting for the socket-limb interface in transfemoral amputees remains a significant challenge. This iterative fitting process largely relies on subjective feedback regarding the patient's comfort and the expertise of the prosthetist. Consequently, this review aims to explore methods for identifying issues at the socket-limb interface through both objective and subjective measurement approaches. All articles available in MEDLINE and Web of Science up to May 2024 were screened and evaluated, with the authors conducting a quality assessment. The socket design was the most frequently studied factor influencing the socket-limb interface (11/25), with investigations addressing challenges such as volume fluctuations (5/25), pressure and shear forces (4/25), femur pistoning (3/25), perspiration and ventilation (2/25), and prosthesis alignment (1/25). Objective measurement methods included gait analysis (6/25), mobility tests (7/25), radiological techniques (8/25), pressure sensors (5/25), and thermal sensors/imaging (2/25), as well as optical and metabolic assessments (3/25). Several studies (17/25) combined objective analyses with subjective questionnaires, such as the Socket Comfort Score (SCS) and Prosthesis Evaluation Questionnaire (PEQ), to evaluate comfort, satisfaction, and prosthetic preferences across varying socket designs. Individualized questionnaires addressing socket design preferences were also employed. Furthermore, a final clustered analysis was conducted to allow comparisons of approaches and tools used for examining similar issues. Despite methodological advancements, a lack of standardization in measurement approaches was evident. The findings of this systematic review highlight significant gaps in current methods for evaluating the socket-limb interface in transfemoral amputees. While both subjective questionnaires, such as the SCS and PEQ, and objective tools, including pressure sensors and motion analyses, offer valuable insights, neither approach alone is sufficient to comprehensively assess prosthetic fit and comfort. Methodological inconsistencies and the absence of standardized protocols further impede advancements in this field. This review underscores the need for a validated and standardized measurement method that combines subjective and objective approaches to enhance evaluation accuracy. Addressing these challenges will enable the development of reliable tools for assessing socket-limb interface quality, especially prosthetic fit and comfort, and drive progress in improving prosthetic functionality and patient outcomes. https://www.crd.york.ac.uk/PROSPERO/view/CRD42023405042, identifier, CRD42023405042.

Measurements of Best, Worst, and Average Socket Comfort Are More Reliable Than Current Socket Comfort in Established Lower Limb Prosthesis Users

The most crucial aspect of a prosthesis is the socket, as it will directly determine gait stability and quality. The current standard of care ischial ramus containment socket is reported to increase coronal stability through gait; however, socket discomfort is the primary complaint among prosthetic users. The purpose of this study is to compare ischial ramus containment to alternatives in the transfemoral amputee population. All subjects were fit with three different sockets: traditional ischial ramus containment, a dynamic socket, and a sub-ischial. In this study, authors hypothesized socket skeletal motion would be equivalent across interventions. Single-blind, repeated-measures, three-period randomized crossover clinical trial. Outcome measures were socket comfort score and skeletal motion, viewed coronally with X-ray measuring the position of the skeleton in relationship to the socket in full weight-bearing and full un-loading. The mean age was 38.2 and mean Amputee Mobility Predictor score was 40. Mean vertical movement, horizontal movement, single limb prosthetic stance, mean femoral adduction in swing and stance, and median socket comfort score were not statistically different. The socket design did not significantly effect skeletal motion and socket comfort. All socket designs are suitable depending on the patient-centric preferences and prosthetist skill set. The comfort of the standard of care transfemoral amputation socket has been widely reported as problematic. A comparison of alternative designs in a controlled clinical trial environment will assist the clinician in understanding the impact of design regarding skeletal motion and comfort. Users could benefit from alternatives applied in clinical practice.

BackgroundPersonalized prosthetic socket design depends upon highly skilled prosthetists. They aim to balance functional human-prosthesis coupling with safe, comfortable load transmission from the prosthesis to the skeleton, through vulnerable skin and soft tissues. Both traditional plaster and computer-aided design and manufacturing (CAD/CAM) methods are iterative, and sharing knowledge is difficult. Evidence-generated (EG) sockets derived from past computer-aided socket design (CASD) records could provide a personalized starting point for limb fitting, potentially reducing time spent on basic design and enabling prosthetists to focus on more highly-skilled customization.ObjectiveThis study aimed to assess the comfort of EG sockets, generated from past CASD records.MethodsA crossover trial compared EG sockets, derived from 163 previous transtibial devices, with conventional clinician-led CAD/CAM sockets. Noninferiority was assessed for the socket comfort score (SCS) outcome measure, and semistructured interviews provided in-depth user analysis. The setting was 3 UK National Health Service clinics, with 17 participants with 19 transtibial amputations.ResultsEG sockets had no statistically significant difference in comfort compared with clinician-led control sockets (median SCS 8.6 for EG sockets and 8.8 for CAD/CAM controls; P=.43, effect size=0.05), but a lower variability in SCS across the group (95% CIs 8.0‐9.0 for EG and 7.5‐9.5 for CAD/CAM devices, respectively). Analysis of interviews revealed themes around fitting session experiences, similarities, and differences between the EG and CAD/CAM control sockets, and residual limb factors impacting perceptions of socket comfort. These provided insights into the participants’ experience of the study and the value of expert prosthetist input in socket design.ConclusionsEG sockets demonstrated noninferiority to conventional clinical CASD practice in terms of socket comfort. Both quantitative and qualitative results indicated how clinician input remains essential and is valued by prosthesis users. Work is underway to incorporate the EG sockets into CASD software such that they can act as a digital starting point for modification by expert clinicians at fitting, potentially reducing time spent on basic design, enabling prosthetists to focus on more highly-skilled customization and co-design with their patients.

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. 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. This is a secondary analysis of cross-sectional data. 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]). 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. 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.

Clinicians and researchers have become aware that achieving normal anatomical adduction of the femoral remnant is an important objective in transfemoral amputation surgery [1-3]. Achieving anatomical adduction has also been a long-established design goal of the transfemoral prosthetic limb [4-11]. The rationale for attaining normal anatomic adduction in the transfemoral amputee is to provide pelvic stabilization [4-6], provide efficient rest-length action of the abductor muscle group [4,8], and reduce the lateral motion of the center of mass of the body, thus producing a smoother and more energy-efficient gait [3]. The degree to which the prosthetic socket can influence the position of the femoral remnant has been disputed. The promotion of surgical stabilization of the through myodesis has been presented on the basis that the prosthesis does little to influence adduction [1-3]. * In 1989, the concept that socket shape and alignment do not affect the position of the femoral remnant in transfemoral amputations was introduced into the body of prosthetic thought. In their research article, Does socket configuration influence the position of the in above-knee amputation? Gottschalk et al. concluded from observations of 50 weight-bearing X-rays of transfemoral prosthetic sockets that no amount of lateral pressure can change the position of the femur and stated the belief that proper anatomical adduction is achieved through specific applied surgical techniques [1]. The sockets X-rayed in Gottschalk et al.'s study comprised both quadrilateral and ischial containment socket designs, and measurements revealed a reported average of 2[degrees] of abduction for all sockets surveyed. In 1989, the contention that socket shape and alignment do not influence the position of the femoral remnant was hotly debated at presentations at the annual meetings of the American Academy of Orthopaedic Surgeons (AAOS) and American Orthotic and Prosthetic Association (AOPA) [1,12,13 (p. 2)]. As of 2009, with numerous meeting presentations having been given and accepting literature having been published [14-15], the debate has cooled considerably. * Two publications from the 1970s, which resulted from an checkout protocol adopted by Fitzsimons Army Medical Center (FAMC) (Figure 1) after the end of America's military involvement in Vietnam, suggest that Gottschalk et al.'s conclusion is incomplete. The publications, as they exist, can be arguably dismissed and were not cited in Gottschalk et al.'s 1989 research. They comprise a two-page technical note in a 1975 prosthetics journal [9] and an abstract published in 1977 [16]. Combined, the publications are slightly more than 1,000 words. However, they serve as provenance for a collection of recently recovered documents related to FAMC's checkout of the transfemoral limb. These previously unpublished documents indicate that femoral adduction was improved, as per clinical practice, with intervention during prosthetic limb manufacture. These documents, gathered from private collections and presented in a special section of the Orthotics and Prosthetics Virtual Library, the FAMC Institutional Memory Preservation Project (http://www.oandplibrary.org/famc/), suggest that our understanding of the relationship between alignment, socket design, and femoral adduction requires further research. [FIGURE 1 OMITTED] The first published reference to FAMC's use of roentgenograms occurs in the second sentence of Long's Allowing normal adduction of in above-knee amputations, which appeared in the December 1975 issue of Orthotics and Prosthetics. Long wrote, X-ray studies carried out at Fitzsimons Army Hospital since March 1974 show that very few above-knee prostheses built in the United States today achieve proper adduction of the femoral stump [9]. It is of interest that the data from Gottschalk et al.'s research support that observation; the divergence and controversy emerge from the conclusion from that data. …

Measuring discomfort-An objective method for quantifying peak pressure discomfort and improved fit in adults with transtibial amputation.

Introduction Microprocessor ankles (MPAs) have recently been developed for persons with lower-limb amputation to overcome known limitations of fixed-ankle energy-storing-and-returning (ESAR) feet. This study aimed to examine differences in patient-reported balance, mobility, socket comfort, and preference between an ESAR foot and an MPA in persons with unilateral transtibial amputation (UTA). Materials and Methods Twenty-three participants with UTA enrolled in an institutional review board–approved, randomized crossover protocol with ESAR (Pacifica LP) and microprocessor-ankle configurations (Kinnex, Freedom Innovations) and a 4-week accommodation period. The outcome measures collected included Activities Specific Balance Confidence Scale (ABC), Prosthesis Evaluation Questionnaire–Mobility Subscale (PEQ-MS), and Prosthetic Limb User Survey of Mobility (PLUS-M). Participants were asked to rate Socket Comfort Score (SCS) while ascending and descending a 15° sloped ramp. Finally, ankle-foot preference and aspects liked and disliked about each configuration were recorded. Results Significant improvements were seen with the MPA in patient-reported mobility in the community (PEQ-MS, ρ = 0.0465) and socket comfort walking and standing on slopes (SCS, ρ < 0.001). Differences in balance confidence (ABC) did not reach a level of significance, whereas improvement in perceived mobility with a prosthesis approached a level of significance (PLUS-M, ρ = 0.102). When asked, 81% of participants preferred the MPA over the ESAR foot. Participants reported positively about the reduced weight of the ESAR foot, whereas they frequently reported that the MPA was better on slopes and uneven terrain. Conclusions The 30° range of motion in the MPA can allow greater mobility when ambulating on typical environmental barriers (e.g., uneven terrain, ramps, and stairs) and allow patients to stand and walk on slopes with less socket discomfort. Most participants preferred the MPA. Frequently reported positive and negative aspects of both systems may be useful for patient consultation regarding ankle-foot technology. This study represents the largest known investigation of MPAs, and the results provide evidence of benefits from MPAs over ESAR feet in persons with UTA.

ObjectiveTo investigate the feasibility of creating an artificial intelligence (AI) algorithm to enhance prosthetic socket shapes for transtibial prostheses, aiming for a less operator-dependent, standardized approach. DesignThe study comprised 2 phases: first, developing an AI algorithm in a cross-sectional study to predict prosthetic socket shapes. Second, testing the AI-predicted digitally measured and standardized designed (DMSD) prosthetic socket against a manually measured and designed (MMD) prosthetic socket in a 2-week within-subject cross-sectional study. SettingThe study was done at the rehabilitation department of the Radboud University Medical Center in Nijmegen, the Netherlands. ParticipantsThe AI algorithm was developed using retrospective data from 116 patients from a Dutch orthopedic company, OIM Orthopedie, and tested on 10 randomly selected participants from Papenburg Orthopedie. InterventionsUtilization of an AI algorithm to enhance the shape of a transtibial prosthetic socket. Main Outcome MeasuresThe algorithm was optimized to minimize the error in the test set. Participants’ socket comfort score and fitting ratings from an independent physiotherapist and prosthetist were collected. ResultsPredicted prosthetic shapes deviated by 2.51 mm from the actual designs. In total, 8 of 10 DMSD and all 10 MMD-prosthetic sockets were satisfactory for home testing. Participants rated DMSD-prosthetic sockets at 7.1 ± 2.2 (n=8) and MMD-prosthetic sockets at 6.6 ± 1.2 (n=10) on average. ConclusionsThe study demonstrates promising results for using an AI algorithm in prosthetic socket design, but long-term effectiveness and refinement for improved comfort and fit in more deviant cases are necessary.