A pneumatic reconfigurable socket for transtibial amputees

Abstract

Many transtibial amputees rate the fit between their residual limb and prosthetic socket as the most critical factor in satisfaction with using their prosthesis. This study aims to address the issue of prosthetic socket fit by reconfiguring the socket shape at the interface of the residual limb and socket. The proposed reconfigurable socket shifts pressure from sensitive areas and compensates for residual limb volume fluctuations, the most important factors in determining a good socket fit. Computed tomography scan images are employed to create the phantom limb of an amputee and to manufacture the reconfigurable socket. The performance of the reconfigurable socket was evaluated both experimentally and numerically using finite element modelling. The study showed that the reconfigurable socket can reduce interface pressure at targeted areas by up to 61%.

An adaptive prosthetic socket for people with transtibial amputation

“…Unlike prior adaptive socket strategies 3 – 15 , our control system was designed to maintain a consistent sensed distance, not pressure. We used sensed distance because it showed the capability to pick up socket fit changes before participants or practitioners 44 , and changes in sensed distance followed changes in limb fluid volume 45 .…”

“…Adaptive sockets are intended to sense changes in socket fit and make proper adjustments before the prosthesis user senses an issue. A number of strategies have been pursued 3 – 19 , the most common being the use of pressure sensing as a control variable and mechanical actuators to adjust socket size 3 – 15 . One of the first attempts to create an adaptive socket used a series of fluid-filled bladders and mechanical valves to adjust socket size 3 .…”

“…Later, investigators pursued development of automatic size-adjusting sockets with powered actuators. Pressure sensors (and in one case shear sensors) were intended to be used for feedback control in most of these studies 4 – 15 . Pirouzi et al .…”

Remodeling of the Fibula Stump After Transtibial Amputation

“… 10 , 11 However, the data given by the authors concern the formation of the femoral stump in animals and do not touch upon the issues of changes in the structural organisation of bone tissue under load in the prosthesis. Recently, the issues of optical identification of model parameters, 12 fabrication of pneumatic reconfigured sockets for proper stump fit, 13 and characterization of soft tissue features after tibial amputation 14 have been developed, which may in the future affect both bone structure and prosthetic outcomes. The available studies of the peroneal bone tissue after transtibial amputation only state the disturbance of bone formation in the form of acuminosity or club-like shape and phenomena of peroneal nerve neuritis.…”

Modification of Ertl Operation for Short Stump

“…Unfortunately, this functionality is not always achievable due to improper sleeve fit and pressure distribution at the interface between the sleeve and residual limb. 18 , 19 Uneven pressure on the residual limb causes pain and tissue damage, pistoning and cyclic “displacement”. In this regard, the research of the authors, 18 who designed a replaceable pneumatic reconfigured socket for the tibial stump, which positively affects both the functional capabilities of the stump and the mechanical abilities of the soft tissues 19 and the distribution of pressure between the stump and the socket, is of considerable interest.…”