Northwestern University Flexible Subischial Vacuum Socket for persons with transfemoral amputation

Abstract

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.

Retracted: Test‐Retest Reliability of Dynamic Balance Performance‐Based Measures Among Adults With a Unilateral Lower‐Limb Amputation

“…Petersen et al [35] studied the 5XSSTamong older individuals with Parkinson disease, and the mean of the two 5-repetition trials were 12.7 (SD = 7.3) seconds and 14.1 (SD = 15.2) seconds. Fatone and Cadwell [37] described 2 cases that investigated the usability of a new subischial socket among adults with transfemoral amputations, and time-to-completion was 9.41-11.81 seconds for the 2 participants (aged 26 and 29 years). Despite being older (mean age = 51 [SD = 12.2] years) than the participants in the Fatone and Cadwell study [37], individuals in our study performed better on the 5XSST per both the best timed trial (8.58 [SD = 2.21] seconds) and the average of 2 trials (8.82 [SD = 2.35] seconds), likely due to our sample having predominantly amputations at the transtibial level as opposed to transfemoral level.…”

“…Fatone and Cadwell [37] described 2 cases that investigated the usability of a new subischial socket among adults with transfemoral amputations, and time-to-completion was 9.41-11.81 seconds for the 2 participants (aged 26 and 29 years). Despite being older (mean age = 51 [SD = 12.2] years) than the participants in the Fatone and Cadwell study [37], individuals in our study performed better on the 5XSST per both the best timed trial (8.58 [SD = 2.21] seconds) and the average of 2 trials (8.82 [SD = 2.35] seconds), likely due to our sample having predominantly amputations at the transtibial level as opposed to transfemoral level. The ICC (3,1) and (3,k) values for our study were consistent with a previous systematic review evaluating reliability of the 5XSST among individuals with back pain and osteoarthritis as well as healthy, community-dwelling adults, where studies with various ICC models were pooled and ICC values ranged from 0.64-0.96 [34].…”

“…The stopwatch was started on "begin" and stopped when the participant assumed a standing position on the fifth repetition [36]. Reliability in adults with a LLA remains unknown, although studies have used this measure in patients with LLA to document response to interventions [37,38]. Participants completed this measure with at least a 2-minute rest between trials to allow for muscle recovery; the examiner demonstrated the test before the first trial.…”

Sockets for Limb Prostheses: A Review of Existing Technologies and Open Challenges

“…Recently, the sub-ischial design has been proposed again with two recent solutions: the sub-ischial Northwestern [14] and the High Fidelity (Hi-Fi) sockets [15]. They constitute new solutions for medium-long stumps, aiming to enhance stability, gait and comfort.…”

“…VAS systems apply a subatmospheric environment through a mechanical or an electrical activation means [27], [14], [39]. They reduce the motion between the residual limb and the socket, thus also reducing pistoning events, increasing the prosthesis control [22], [40]- [42] and allowing lower socket brims [14]. They are also considered to improve wound healing and reduce volume fluctuations [42], [43].…”