Socket Comfort Research Articles

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

ObjectiveTo compare comfort and functional performance of the Northwestern University Flexible Subischial Vacuum (NU-FlexSIV) Socket with the ischial containment (IC) socket in persons with unilateral transfemoral amputation. DesignRandomized crossover trial with two 7-week periods. SettingPrivate prosthetic clinics and university research laboratory. ParticipantsA total of 30 enrolled (N=30); 25 participants completed the study with full (n=18) or partial data (n=7). InterventionsTwo custom-fabricated sockets (IC and NU-FlexSIV), worn full-time for 7 weeks, with testing at 1, 4, and 7 weeks after socket delivery. Main Outcome MeasuresThe primary outcome was change in Socket Comfort Score (SCS) at 7 weeks. Secondary outcomes at 7 weeks included the Orthotic and Prosthetic Users’ Survey (OPUS) to assess lower extremity functional status, health-related quality of life, and satisfaction with device, as well as the 5-Times Rapid Sit-to-Stand Test, Four Square Step Test, and T-Test of Agility to assess functional performance. ResultsAt 7 weeks, the mean SCS for IC (7.0±1.7) and NU-FlexSIV (8.4±1.1) Sockets were significantly different (P<.001; 95% confidence interval, 0.8-2.3). Results from a linear mixed-effects model, accounting for data from all time points, indicated that the SCS was 1.7 (SE=0.45) points higher for the NU-FlexSIV Socket (P<.001). For the secondary outcomes, only OPUS satisfaction with device was significantly better in the NU-FlexSIV Socket after accounting for all data points. ConclusionsThe results suggest that after 7 weeks’ accommodation, the NU-FlexSIV Socket was more comfortable and led to greater satisfaction with device than the IC socket in persons with unilateral transfemoral amputation and K3/K4 mobility. Other patient-reported outcomes and function were no different between sockets.

Comparison of patient-reported and functional outcomes following transition from mechanical to microprocessor knee in the low-activity user with a unilateral transfemoral amputation.

The Scottish Specialist Prosthetics Service has provided microprocessor knees (MPKs) through the National Health Service since 2014, predominantly to high-activity transfemoral amputations (TFAs). Benefits of MPKs to the lower-activity TFA are less established in the literature. This study aimed to compare patient-reported and functional measures in low-activity TFAs transitioning from a mechanical knee to a MPK. This is a retrospective cohort analysis of low-activity individuals with a unilateral TFA provided with an MPK. Patient-reported measures were recorded in routine clinical care before and 6 months after MPK provision. These included HR-QoL (EQ-5D-5L Health Index), Activities Balance Confidence score, Prosthetic Limb User Survey of Mobility, falls frequency, use of walking aids, and Socket Comfort Score. Functional measures included the two-minute walk test (2MWT), L-test, and Amputee Mobility Predictor score, and three-dimensional gait analysis was used to generate a Gait Profile Score (GPS). The primary outcomes were HR-QoL and GPS. Forty-five participants fulfilled the inclusion criteria. Thirty-one had pre-MPK and post-MPK measures, of which 15 had three-dimensional gait analysis. The mean age (n = 31) was 60 years (SD 11), and 68% were male. HR-QoL and GPS did not significantly improve with MPK provision (p = 0.014 and p = 0.019); Amputee Mobility Predictor score, L-Test, 2MWT, falls, and Activities Balance Confidence score showed a significant improvement with MPK provision (p < 0.001). Although no statistically significant change in the primary outcomes was measured, there were sufficient data to support MPK provision in low-activity prosthetic users with participants demonstrating improvements in balance, 2MWT, falls frequency, and confidence.

A Biomimetic Adapter for Passive Self-alignment of Prosthetic Feet.

Dynamic alignment of lower limb prostheses is subjective and time-consuming. Compensatory gait strategies caused by prosthesis misalignment can negatively affect lower limb amputees who cannot access a certified prosthetist for alignment adjustments. The objective of this study is to evaluate a novel six-degrees-of-freedom passive transtibial prosthetic adapter that self-aligns during various phases of gait. This self-aligning adapter may benefit service members and veterans stationed or living far from a clinical facility. Four transtibial amputee subjects, aged 47 to 62 (mean: 55.75) years with mean weight of 163.6 lbs and mean K-level of 3.25, walked at self-selected speeds on a 10-m level walkway. Subjects walked with the self-aligning and a size- or weight-matched control adapter, assembled to a commercially available energy-storing-and-returning foot and their own socket, with 22-mm alignment perturbations in the anterior, posterior, medial, or lateral directions. Subjects were blinded to both adapter type and misalignment. Socket moments, spatiotemporal gait parameters, and subjective socket comfort were recorded. Preliminary results showed improvements in mean peak socket moments and step length differential with the self-aligning adapter across all alignments. Walking speed and prosthesis-side base of support showed little change in all configurations. Prosthesis-side stance duration and Functional Ambulation Profile Score increased with the self-aligning adapter in some alignments. Patient-reported socket comfort increased slightly with the self-aligning adapter across all misalignments. Subjects maintained similar walking speeds and experienced greater gait symmetry and reduced sagittal plane peak moments with the self-aligning adapter when exposed to misalignments. These trends suggest a benefit to transtibial amputees from a reduction in secondary gait effects from prosthesis misalignments. Additionally, a wider range of acceptable prosthesis alignments may be possible with the self-aligning adapter. Subsequent trials are underway to evaluate the self-aligning adapter in real-world environments like walking on uneven terrains, stairs, ramps, and abrupt turns.

Sustainable, affordable and functional: reimagining prosthetic liners in resource limited environments

Purpose The purpose of this study was to evaluate function and performance of unilateral trans-tibial prosthesis users wearing an affordable liner in three types of socket designs. Methods Five unilateral trans-tibial amputees participated, were provided an Affordable Ethyl-Vinyl-Acetate Roll-On liner (AERO) roll-on liner with patella tendon bearing (PTB) prosthesis, PE-Lite liner with PTB prosthesis, and an (AERO) liner with total-surface bearing (TSB) prosthesis. A battery of outcome measures; step-counts, socket comfort score (SCS), orthotics prosthetics user survey (OPUS) and socket pressure measurement during walking were administered. Results Comparisons of step-counts indicated that PTB-AERO (3604 ± 815) was not significantly different than PTB-PE-Lite (3386 ± 942). Mean SCS was 9.2 ± .83 and 7.2 ± 2.1 for PTB-AERO and PTB-PE-Lite. A 6.6% decrease in mean peak pressure was observed between PTB-PE-Lite and TSB-AERO, and 3.2% difference between PTB-PE-Lite and PTB-AERO. Conclusion An affordable ($20 USD) and sustainably fabricated prosthesis liner was created and evaluated in trans-tibial prosthesis users. These initial results garner preliminary support for use of the AERO prosthetic liner and continued research. Implications for rehabilitation Lower limb prosthetics in less-resourced settings can leverage locally sourced and affordable materials to fabricate roll-on liners for use in modern prosthetic sockets. The cost of the AERO liner is markedly lower than current standard of care gel liners, yet still facilitates use of current prosthetic sockets.

Selecting, Administering, and Interpreting Outcome Measures among Adults with Lower-Limb Loss: An Update for Clinicians.

To summarize outcome measurement research among adults with lower-limb loss (LLL) for clinicians. Houghton Scale, Prosthetic Evaluation Questionnaire-mobility subscale (PEQ-m), Prosthetic Limb Users Survey of Mobility (PLUS-M™), Activities-Specific Balance Confidence Scale (ABC), Amputee Mobility Predictor (AMP), Comprehensive High-Level Activity Mobility Predictor, Four Square Step Test (FSST), Narrowing Beam Walking Test (NBWT), L Test, 10 Meter Walk Test (10MWT), and 6 Minute Walk Test (6MWT) are appropriate for evaluating individual patient changes post-LLL. Post-LLL, Socket Comfort Score, Patient-Specific Functional Scale, Patient-Reported Outcomes Measurement Information System 29-Item Profile, Timed Up and Go, and 2 Minute Walk Test may be more appropriate for evaluating groups. Minimal detectable change is available for 15/20 reviewed measures. Many measures differ between mobility levels. Quick, reliable measures for evaluating patient functional change include ABC, PEQ-m, PLUS-M™, FSST, and L Test; when resources allow, NBWT, 10MWT, 6WMT and AMP may be considered.

Three-dimensional printing in prosthetics: Method for managing rapid limb volume change.

During post-amputation recovery or rapid body mass change, residual limb volume can change quickly, requiring frequent adjustments or replacement of the socket to maintain fit. The aim of this pilot test was to evaluate the feasibility of using a three-dimensional-printed insert to extend the service life of a prosthetic socket after substantial residual limb volume loss. One research subject with a well-fitting transtibial prosthetic socket had an oversized socket fabricated to simulate substantial limb volume loss. The digital shapes of the oversized and well-fitting sockets were used to create a three-dimensional-printed insert to restore fit. Two-minute walk test distance decreased when using the oversized socket without the insert, but not when using the socket with the insert. Socket comfort score was 8+ under all conditions. These results suggest that three-dimensional-printed inserts may be an effective method of extending the service life of prosthetic sockets when rapid limb volume loss occurs. Three-dimensional (3D) printing gives prosthetists a new tool to manage large volume changes without refabricating entire sockets. Sockets can be fabricated in anticipation of volume gain/loss, using replaceable 3D-printed inserts to maintain fit and comfort.

Oxygen Consumption and Speed Performance of a Runner with Amputation Wearing an Elevated Vacuum Running Prosthesis

ABSTRACT Introduction Persons with lower-limb differences are increasingly seeking out a means to participate in sport and running activities. Suspension of the running-specific prosthesis (RSP) during high-intensity running is crucial for safety and optimal running performance. The vacuum-assisted socket system (VASS) provides enhanced proprioception and residual limb volume stability during walking; however, utilization of the VASS in an individual fit with an RSP has yet to be explored in case or empirical studies. We report outcomes of a recreational running transtibial prosthesis user wearing a novel VASS-RSP. Methods A 33-year-old man with transtibial amputation was provided an RSP with a VASS and performed outcome measures while wearing the VASS-RSP and non–VASS-RSP. He performed a series of straight and counterclockwise (CCW) curve track 40-m runs while speed gates recorded split and total time. The patient also performed a 10-minute treadmill run oxygen consumption was determined, and Socket Comfort Scores (SCS) were recorded. Results No significant differences in track running trials were observed; straight track running speeds were similar VASS (5.37 ± 0.06 m/s) and non–VASS-RSP (5.37 ± 0.16 m/s), [t(1) = 0.320, P = 0.979]. Curve track speeds improved while wearing the VASSRSP (4.72 ± 0.09 m/s) compared with the non–VASS-RSP (4.66 ± 0.03 m/s) [t(2) = 0.846, P = 0.487]. Speeds were significantly faster during straight track running (5.37 ± 0.08 m/s) than during curve track running (4.70 ± 0.07 m/s) when both RSP configurations were combined [t(4) = 15.8, P = 0.001]. Net oxygen consumption reduced while wearing VASS-RSP (24.6 mL/kg per minute) compared with non–VASS-RSP (29.2 mL/kg per minute). Socket comfort during outcome measures improved 33% while wearing the VASS-RSP. Conclusions The patient preferred using the VASS-RSP while performing running exercises, and some outcome measures comparing the two suction suspension systems support the patient values. The novel VASS system should be further tested to determine potential utility for running exercise and sport interventions for persons with amputation.

Comparative Effectiveness of Microprocessor-Controlled and Carbon-Fiber Energy-Storing-and-Returning Prosthetic Feet in Persons with Unilateral Transtibial Amputation: Patient-Reported Outcome Measures

ABSTRACT 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 &lt; 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.

Sustainable Development: A Below-Knee Prostheses Liner for Resource Limited Environments

AbstractThis research sought to develop a fabricable prosthetic liner that could be fabricable, intuitive, and a cost-effective means of providing advanced prosthetics in developing settings. An affordable ethyl-vinyl-acetate roll-on (AERO) liner for permitting a total surface bearing suction socket design was created and provided to a single participant for in vivo outcome measurements. The liner was fabricated from locally produced low-density ethyl-vinyl-acetate (EVA) foam. A liner fabrication process was developed and described, and one participant was provided 3 mm and 6 mm AERO liner variants for outcome evaluations. Six-minute walk test, residual limb temperature, and socket comfort score (SCS) while in AERO liner were collected. Thirty-day step counts of AERO liner with prosthesis and thermoplastic elastomer (TPE) liner with prosthesis were collected. The results of in vivo evaluations indicate increased speed, slightly higher residuum temperature, and increased comfort of the 6 mm AERO liner. Pedometer tallied step counts for the AERO liner and TPE liner prostheses were similar. The 6 mm AERO liner provided the best comfort and function of the two thicknesses in liners, and step count data indicated that the volume of patient activity was similar to when wearing the TPE liner prosthesis. Roll-on fabricable low-cost liners offer an affordable means of providing total surface bearing suction prostheses for resource limited environments (RLE). A prosthetist or technician can use the existing skills and lab to create liners.

Dynamic alignment using external socket reaction moments in trans-tibial amputees

BackgroundProsthetic alignment is used to optimize prosthetic functioning and comfort. Spatio-temporal and kinematic gait parameters are generally observed to guide this process. However, they have been shown to be influenced by compensations, which reduces their sensitivity to changes in alignment. Alternatively, the use of moments working at the base of the prosthetic socket, external socket reaction moments (ESRM), has been proposed to quantify prosthetic alignment. Research questionTo investigate if a predetermined kinetic alignment criterion, 0Nm averaged over the stance phase, can be used to fine-tune prosthetic alignment. Methods10 transtibial amputees were included in this intervention study. Firstly, their prostheses were aligned using conventional alignment procedures. Kinetic parameters and Socket Comfort Score (SCS) were measured in this initial alignment (IA) condition. Subsequently, the coronal plane ESRM during gait was presented to the prosthetist in real time using a Gait Real-time Analysis Interactive Lab. The prosthetist iteratively adapted the prosthetic alignment towards a predetermined average ESRM during the stance phase of 0 Nm. At the Final Alignment (FA), kinetic parameters and SCS were measured again and a paired sample t-test was performed to compare ESRMs and SCSs between alignments. ResultsA significant (p < 0.001) change was found in the absolute coronal plane ESRM (mean ± SD) from IA (|0.104| ± 0.058 Nm/kg) to FA (|0.012| ± 0.015 Nm/kg). In addition a significant (p < 0.001) change of the external coronal adduction knee moments was observed from IA (−0,127 ± 0.079 Nm/kg) to FA (−0.055 ± 0.089 Nm/kg), however this change was more variable among participants. On average, no significant (p = 0.37) change in the SCS was observed. SignificanceWhile this study shows the potential of quantifying and guiding alignment with the assistance of kinetic criteria, it also suggests that a sole reliance on the ESRM as a single alignment criterion might be too simple.

Improvement in Functional Outcomes with the Infinite Socket

ABSTRACT Introduction The prosthetic socket, which provides an important patient interface for weight bearing and mobility, cannot adequately account for the dynamics of the residual limb, and problems with pain, skin breakdown, verrucous hyperplasia, and bursitis are frequent. To address these issues, LIM Innovations, a prosthetics manufacturer, has developed the Infinite Socket, an adjustable, custom-molded modular socket made of a carbon fiber frame and a two-part tensioning system that can be adjusted by the user. Materials and Methods Patients with transtibial or transfemoral amputations were asked to participate in this study between the period of June 30, 2015, and January 1, 2017, if they had a standard-of-care thermoplastic socket and were dissatisfied. Patients were fit with an Infinite Socket, and functional outcome tests were performed at the time of the Infinite Socket fitting. It was hypothesized that the Infinite Socket would improve functional outcomes compared with the subjects' legacy prosthetic sockets. Results One hundred twenty-seven patients with limb loss (18 transtibial and 109 transfemoral) participated in this study. The mean age of participants was 48 years (range, 19–82) and 82% were male. Data indicate that the Infinite Socket had superior outcomes compared with legacy standard-of-care prosthetic sockets for socket comfort scores (7.64 ± 2.00 vs. 4.52 ± 2.22, P &lt; 0.0001), 2-minute walk test (108.80 ± 31.28 vs. 101.53 ± 33.96, P = 0.007), and the Four-Step Square Test (17.01 ± 12.14 vs. 21.57 ± 18.52, P = 0.005). There was no statistically significant difference in the L Test (30.98 ± 27.51, 36.31 ± 45.64, P = 0.246). Conclusions A new modular, patient-adjustable prosthetic socket demonstrated improved functional outcomes compared with the legacy standard-of-care prosthetic socket. Participants reported higher socket comfort scores and mobility scores were improved for the two-minute walk test and Four-Step Square Test for those using the Infinite Socket.

P 036 - Pressure mapping analysis for forward and backward gait

To compare comfort and functional performance of the Northwestern University Flexible Subischial Vacuum (NU-FlexSIV) Socket with the ischial containment (IC) socket in persons with unilateral transfemoral amputation.Randomized crossover trial with two 7-week periods.Private prosthetic clinics and university research laboratory.A total of 30 enrolled (N=30); 25 participants completed the study with full (n=18) or partial data (n=7).Two custom-fabricated sockets (IC and NU-FlexSIV), worn full-time for 7 weeks, with testing at 1, 4, and 7 weeks after socket delivery.The primary outcome was change in Socket Comfort Score (SCS) at 7 weeks. Secondary outcomes at 7 weeks included the Orthotic and Prosthetic Users’ Survey (OPUS) to assess lower extremity functional status, health-related quality of life, and satisfaction with device, as well as the 5-Times Rapid Sit-to-Stand Test, Four Square Step Test, and T-Test of Agility to assess functional performance.At 7 weeks, the mean SCS for IC (7.0±1.7) and NU-FlexSIV (8.4±1.1) Sockets were significantly different (P<.001; 95% confidence interval, 0.8-2.3). Results from a linear mixed-effects model, accounting for data from all time points, indicated that the SCS was 1.7 (SE=0.45) points higher for the NU-FlexSIV Socket (P<.001). For the secondary outcomes, only OPUS satisfaction with device was significantly better in the NU-FlexSIV Socket after accounting for all data points.The results suggest that after 7 weeks’ accommodation, the NU-FlexSIV Socket was more comfortable and led to greater satisfaction with device than the IC socket in persons with unilateral transfemoral amputation and K3/K4 mobility. Other patient-reported outcomes and function were no different between sockets.

Functional impact of a new prosthetic foot design in transtibial amputation, a comparative study

Prosthetic feet designs are complex with energy storage and shock absorption characteristics. These feet store energy in the heel and the mid-foot during loading and release energy at push off. Device selection is based on subjective criteria because of a lack of quantitative methods. Studies have compared different prosthetic feet however, did not include functional outcome and rating for comfort. This study evaluated a new prosthetic foot (Pro-Flex XC TS and Pro-Flex LP TS) from Ossur. Prospective, comparative study that included 10 trans-tibial prosthetic users walking with current foot design vs. the Pro-Flex XC/LP TS outcomes included the Prostheses Evaluation Questionnaire, Socket Comfort Scale, 6 MWT Performance, L-Test, Activities-specific Balance Confidence Scale and temporal spatial parameters of gait measured with original prosthetic device and the test devices used for 4 weeks. With the Pro-Flex XC TS and Pro-Flex LP TS, most subjects demonstrated average 10% increase in walking velocity, improved scores in the PEQ and 15% increase walking capacity. Improved L test time and swing/stance ratio. Most had improvement in the ABC, with small non-significant decrease was reported in 4 subjects. The newly designed Pro-Flex XC TS and Pro-Flex LP TS foot produce improvement in walking and functional rating as well as benefits in self rated performance and stability. This new foot design should be considered as and excellent choice for patients with functional ambulatory category 2–4. Tests of function and satisfaction should be used in future prosthetic foot trials and included in foot prescription.

Residual limb fluid volume change and volume accommodation

Fluctuations in limb volume degrade prosthesis fit and require users to accommodate changes using management strategies, such as donning and doffing prosthetic socks. To examine how activities and self-report outcomes relate to daily changes in residual limb fluid volume and volume accommodation. Standardized, two-part laboratory protocol with an interim observational period. Participants were classified as "accommodators" or "non-accommodators," based on self-report prosthetic sock use. Participants' residual limb fluid volume change was measured using a custom bioimpedance analyzer and a standardized in-laboratory activity protocol. Self-report health outcomes were assessed with the Socket Comfort Score and Prosthesis Evaluation Questionnaire. Activity was monitored while participants left the laboratory for at least 3 h. They then returned to repeat the bioimpedance test protocol. Twenty-nine people were enrolled. Morning-to-afternoon percent limb fluid volume change per hour was not strongly correlated to percent time weight-bearing or to self-report outcomes. As a group, non-accommodators ( n = 15) spent more time with their prosthesis doffed and reported better outcomes than accommodators. Factors other than time weight-bearing may contribute to morning-to-afternoon limb fluid volume changes and reported satisfaction with the prosthesis among trans-tibial prosthesis users. Temporary doffing may be a more effective and satisfying accommodation method than sock addition. Clinical relevance Practitioners should be mindful that daily limb fluid volume change and prosthesis satisfaction are not dictated exclusively by activity. Temporarily doffing the prosthesis may slow daily limb fluid volume loss and should be investigated as an alternative strategy to sock addition.

Effects of Vacuum-Assisted Socket Suspension on Energetic Costs of Walking, Functional Mobility, and Prosthesis-Related Quality of Life

ABSTRACT Introduction Proper suspension is critical to maintaining socket comfort and fit. Vacuum-assisted socket suspension (VASS) improves fit and comfort by reducing peak socket pressure and pistoning of the residual limb. The purpose of this study was to quantify the effects of VASS on metabolic costs of gait and performance-based outcomes by evaluating changes in these measures immediately after altering suspension and to compare self-reported outcome measures between groups of VASS and non-VASS users. Materials and Methods Eighteen current VASS users and 18 non-VASS users, all of whom were active community ambulators, participated in two related studies. For study 1, VASS users completed three tasks in the following order: 1) a quantitative gait analysis, 2) function and mobility tests (10-m walk test [10MWT] and timed up and go [TUG]); and 3) 6 minutes of walking at self-selected speed (SSS) to determine energetic costs of walking and socket comfort. Participants performed each task under three suspension conditions, in random order, before proceeding to the next task. The conditions were altering VASS by inactivating the vacuum and blocking the one-way valve. Participants completed tasks immediately after alterations in suspension; that is, we provided no specific accommodation period. All tasks in study 1 were completed during a single testing session. For study 2, both VASS and non-VASS subjects completed electronic versions of surveys to assess prosthetic use and locomotor function including sections of the Prosthetic Evaluation Questionnaire. Results Study 1: There was no effect of suspension on cost of transport (p = 0.47 for main effect of suspension). However, participants performed TUG in shorter time using VASS and suction (p = 0.02 VASS vs. sleeve; p = 0.049 suction vs. sleeve; p = 0.54 VASS vs. suction) and performed the 10MWT with greater speed while using VASS compared with both suction (p = 0.027) and sleeve (p = 0.011). The use of VASS resulted in a significant within-subject increase of 1.5 and 3 points in socket comfort compared to suction (p = 0.001) and sleeve (p = 0.001), respectively. Study 2: There were no significant differences in any self-reported outcomes measures between VASS and non-VASS users. Conclusions In absence of active vacuum, current users of VASS experience an immediate reduction in comfort, presumably reflecting worse fit, which may limit their ability to attain faster walking speeds but which does not have an immediate negative affect on the cost of transport. The self-reported measures used to quantify the effects of suspension on prosthetic use, locomotor capabilities, and domains reflecting prosthesis-related quality of life may have been ill-suited for identifying difference in the high-functioning heterogeneous population considered.

Effects of socket size on metrics of socket fit in trans-tibial prosthesis users

The purpose of this research was to conduct a preliminary effort to identify quantitative metrics to distinguish a good socket from an oversized socket in people with trans-tibial amputation. Results could be used to inform clinical practices related to socket replacement. A cross-over study was conducted on community ambulators (K-level 3 or 4) with good residual limb sensation. Participants were each provided with two sockets, a duplicate of their as-prescribed socket and a modified socket that was enlarged or reduced by 1.8mm (∼6% of the socket volume) based on the fit quality of the as-prescribed socket. The two sockets were termed a larger socket and a smaller socket. Activity was monitored while participants wore each socket for 4 weeks. Participants’ gait; self-reported satisfaction, quality of fit, and performance; socket comfort; and morning-to-afternoon limb fluid volume changes were assessed. Visual analysis of plots and estimated effect sizes (measured as mean difference divided by standard deviation) showed largest effects for step time asymmetry, step width asymmetry, anterior and anterior-distal morning-to-afternoon fluid volume change, socket comfort score, and self-reported utility. These variables may be viable metrics for early detection of deterioration in socket fit, and should be tested in a larger clinical study.

The influence of a hydraulic prosthetic ankle on residual limb loading during sloped walking.

In recent years, numerous prosthetic ankle-foot devices have been developed to address the demands of sloped walking for individuals with lower-limb amputation. The goal of this study was to compare the performance of a passive, hydraulic ankle-foot prosthesis to two related, non-hydraulic ankles based on their ability to minimize the socket reaction moments of individuals with transtibial amputation during a range of sloped walking tasks. After a two-week accommodation period, kinematic data were collected on seven subjects with a transtibial amputation walking on an instrumented treadmill set at various slopes. Overall, this study was unable to find significant differences in the torque at the distal end of the prosthetic socket between an ankle-foot prosthesis with a hydraulic range-of-motion and other related ankle-foot prosthesis designs (rigid ankle, multiaxial ankle) during the single-support phase of walking. In addition, socket comfort and perceived exertion were not significantly different for any of the ankle-foot prostheses tested in this study. These results suggest the need for further work to determine if more advanced designs (e.g., those with microprocessor control of hydraulic features, powered ankle-foot designs) can provide more biomimetic function to prosthesis users.

Northwestern University Flexible Subischial Vacuum Socket for persons with transfemoral amputation: Part 2 Description and Preliminary evaluation.

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.

Assessment Measures for Evaluation of Outcomes in Transtibial Amputees resulting from Trauma: A Systematic Review

ABSTRACT Introduction Amputations secondary to high-energy open fractures and blast, ballistic, and crush injuries to the lower extremity are common challenges faced by military and civilian orthopaedic surgeons. A lack of consensus on domains to be measured and quality of prosthetic rendering pose methodological challenges to researchers and clinicians alike. We conducted a systematic review of the literature to summarize which domains of health, prosthetic fit, and prosthetic alignment are used to describe outcomes for lower extremity amputees secondary to trauma. Materials and methods A search of PubMed, Cochrane, and Embase was conducted including the keywords: Amputation, traumatic, transtibial, survey, and metric. Articles were selected based on whether the study assessed clinical outcomes following transtibial amputation following trauma. Experimental and observational comparative studies and case series were included. Study characteristics and results were extracted using standardized data forms. The number of unique measures recorded, the frequency of measure use, and the number outcome measures were validated and were compiled. Results Literature search ultimately resulted in 273 articles being included. A conceptual model was constructed to capture and organize the causal and temporal relationships between fit, alignment, and outcome. Of the 68 articles that used questionnaires to assess prosthetic fit, 37 used a questionnaire designed specifically for the study as opposed to a published or validated tool. Four validated tools were commonly used to capture patient satisfaction with a prosthesis: The OPUS, PEQ, TAPES, and the Socket Comfort Fit Score. Prosthetic alignment was assessed in 19 of 273 articles. One article validated the use of an alignment jig for quantification and prescription of prostheses. Totally, 8 of 19 articles assessing alignment used gait analysis and ground reaction forces to capture differences due to alterations in alignment. Discussion Choice of an appropriate outcome measure is critical in generating evidence to support treatment decisions for patients undergoing transtibial amputation after trauma. We found a large number of different tools being used across studies, making results difficult to compare. Prosthetic fit and comfort of the residual limb in the socket and the alignment of the socket and the shank of the prosthesis make up the foundation for the proposed conceptual model. In order to distinguish effects attributable to an intervention of interest vs the impact of the quality of the socket fitting, validation of a clinically objective scoring system to assess socket fit is necessary. Conclusion A large number of different tools are currently being used across studies to assess outcomes for transtibial amputees resulting from trauma, and there is a need for development and validation of a clinically objective scoring system to assess socket fit. Baumgartner R, Morshed S. Assessment Measures for Evaluation of Outcomes in Transtibial Amputees resulting from Trauma: A Systematic Review. The Duke Orthop J 2017;7(1):23-29.

The Effect of Alignment Changes on Unilateral Transtibial Amputee's Gait: A Systematic Review.

IntroductionProsthetic alignment, positioning of a prosthetic foot relative to a socket, is an iterative process in which an amputee’s gait is optimized through repetitive optical gait observation and induction of alignment adjustments when deviations are detected in spatiotemporal and kinematic gait parameters. An important limitation of the current prosthetic alignment approach is the subjectivity and the lack of standardized quantifiable baseline values. The purpose of this systematic review is to investigate if an optimal alignment criterion can be derived from published articles. Moreover, we investigated the effect of alignment changes on spatiotemporal, kinematic and kinetic gait parameters.ResultsA total of 11 studies were included, two controlled before-and-after studies and nine-interrupted time series studies.DiscussionThe results demonstrate that alignment changes have a predictable influence on the included kinetic parameters. However, the effect of alignment changes on spatio-temporal and kinematic gait parameters are generally unpredictable. These findings suggest that it is imperative to include kinetics in the process of dynamic prosthetic alignment. Partially this can be established by communication with the prosthetic user in terms of perceived socket comfort, but the use of measurement tools should also be considered. While current literature is not conclusive about an optimal alignment, future alignment research should focus on alignment optimisation based on kinetic outcomes.