BackgroundGood prosthetic suspension system secures the residual limb inside the prosthetic socket and enables easy donning and doffing. This study aimed to introduce, evaluate and compare a newly designed prosthetic suspension system (HOLO) with the current suspension systems (suction, pin/lock and magnetic systems).MethodsAll the suspension systems were tested (tensile testing machine) in terms of the degree of the shear strength and the patient’s comfort. Nine transtibial amputees participated in this study. The patients were asked to use four different suspension systems. Afterwards, each participant completed a questionnaire for each system to evaluate their comfort. Furthermore, the systems were compared in terms of the cost.ResultsThe maximum tensile load that the new system could bear was 490 N (SD, 5.5) before the system failed. Pin/lock, magnetic and suction suspension systems could tolerate loads of580 N (SD, 8.5), 350.9 (SD, 7) and 310 N (SD, 8.4), respectively. Our subjects were satisfied with the new hook and loop system, particularly in terms of easy donning and doffing. Furthermore, the new system is considerably cheaper (35 times) than the current locking systems in the market.ConclusionsThe new suspension system could successfully retain the prosthesis on the residual limb as a good alternative for lower limb amputees. In addition, the new system addresses some problems of the existing systems and is more cost effective than its counterparts.

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Abstract-Poor suspension increases slippage of the residual limb inside the socket during ambulation. The main purpose of this article is to evaluate the pistoning at the prosthetic linersocket interface during gait and assess patients' satisfaction with two different liners. Two prostheses with seal-in and locking liners were fabricated for each of the 10 subjects with transtibial amputation. The Vicon motion system was used to measure the pistoning during gait. The subjects were also asked to complete a Prosthesis Evaluation Questionnaire. The results revealed higher pistoning inside the socket during gait with the locking liner than with the seal-in liner (p < 0.05). The overall satisfaction with the locking liner was higher (p < 0.05) because of the relative ease with which the patients could don and doff the device. As such, pistoning may not be the main factor that determines patients' overall satisfaction with the prosthesis and other factors may also contribute to comfort and satisfaction with prostheses. The article also verifies the feasibility of the Vicon motion system for measuring pistoning during gait.

Background: One of the main indicators of the suspension system efficiency in lower limb prostheses is vertical displacement or pistoning within the socket. Decreasing pistoning and introducing an effective system for evaluating pistoning could contribute to the amputees’ rehabilitation process.Objectives: The main objective of this study was to review existing research studies that examine the occurrence of pistoning in lower limb prosthesis with different techniques in static (standing) and dynamic (walking and jumping) positions.Study Design: Literature review.Methods: Keywords related to slippage, suspension, pistoning and vertical movement in lower limb prosthetics were used to search the literature available in PubMed, ScienceDirect, Web of Science and Google Scholar databases. Sixteen articles were selected for further analysis according to the selection criteria.Results: The following methods have been used to measure the occurrence of pistoning in prosthetic limbs: radiological methods, photographic technique, motion analysis system, sensor and spiral computerized tomography (CT). Pistoning was measured both in standing and walking.Conclusions: The results of this review reveal that further research is needed to develop and evaluate easy, accurate and safe methods of measuring pistoning. Future studies should provide a gold standard for the acceptable range of pistoning in a prosthetic socket.Clinical relevanceThis literature review contributes to a further understanding of lower limb prosthetic biomechanics by highlighting the strengths and weaknesses of the techniques that are currently available for evaluating the occurrence of pistoning in a prosthetic socket. It provides a useful overview of the current methods of measuring residual limb movements relative to the socket and liner, and will be of use for both practitioners and researchers in prosthetics and orthotics fields.