Double-Wall, Transtibial Prosthetic Socket Fabricated Using Selective Laser Sintering: A Case Study

Rogers, Bill; Stephens, Sean; Gitter, Andrew; Bosker, Gordon; Crawford, Richard H.

doi:10.1097/00008526-200012030-00007

Cited by 39 publications

(24 citation statements)

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“…The CAD data can then be sent to a rapid prototyping machine for fabrication. The use of rapid prototyping machine to fabricate prosthetic socket has been reported in the literature [31][32]. With CAD/ CAM techniques, monolimbs can be tailored to vary wall thickness and geometry of the shank.…”

Section: Resultsmentioning

confidence: 99%

Finite-element analysis to determine effect of monolimb flexibility on structural strength and interaction between residual limb and prosthetic socket

Lee

Zhang

Boone³

et al. 2004

JRRD

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Abstract-Monolimb refers to a kind of transtibial prostheses having the socket and shank molded into one piece of thermoplastic material. One of its characteristics is that the shank is made of a material that can deform during walking, which can simulate ankle joint motion to some extent. Changes in shank geometry can alter the stress distribution within the monolimb and at the residual limb-socket interface and, respectively, affect the deformability and structural integrity of the prosthesis and comfort perceived by amputees. This paper describes the development of a finite-element model for the study of the structural behavior of monolimbs with different shank designs and the interaction between the limb and socket during walking. The von Mises stress distributions in monolimbs with different shank designs at different walking phases are reported. With the use of distortion energy theory, possible failure was predicted. The effect of the stiffness of the monolimb shanks on the stress distribution at the limb-socket interface was studied. The results show a trend-the peak stress applied to the limb was lowered as the shank stiffness decreased. This information is useful for future monolimb optimization.

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Section: Resultsmentioning

confidence: 99%

Finite-element analysis to determine effect of monolimb flexibility on structural strength and interaction between residual limb and prosthetic socket

Lee

Zhang

Boone³

et al. 2004

JRRD

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“…Some researchers however, have proposed compliant socket designs to offer relief in vulnerable regions, such as near bony protrusions. For instance by varying the socket wall thickness and by introducing deformable structures [19], by introducing a variable spacing between a flexible inner and rigid outer socket [20], and finally by spatially varying the elastic material properties of the socket [21]. The preliminary findings of the latter study were reduced contact pressures for a compliant socket compared to a conventional socket.…”

Section: Introductionmentioning

confidence: 99%

Automated and Data-driven Computational Design of Patient-Specific Biomechanical Interfaces

Moerman¹,

Sengeh²,

Herr³

2016

Preprint

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Abstract-Biomechanical interfaces are mechanical structures that form the connection between a device and a tissue region, and, through appropriate load transfer, aim to minimize tissue discomfort and injury. A patient-specific and data-driven computational framework for the automated design of biomechanical interfaces is presented here. Optimization of the design of biomechanical interfaces is complex since it is affected by the interplay of the geometry and mechanical properties of both the tissue and the interface. The proposed framework is presented for the application of transtibial amputee prostheses where the interface is formed by a prosthetic liner and socket. Conventional socket design and manufacturing is largely artisan, non-standard, and insufficiently data-driven, leading to discrepancies between the quality of sockets produced by different prosthetists. Furthermore, current prosthetic liners are often not patient-specific. The proposed framework involves: A) non-invasive imaging to record patient geometry, B) indentation to assess tissue mechanical properties, C) data-driven and automated creation of patientspecific designs, D) patient-specific finite element analysis (FEA) and design evaluation, and finally E) computer aided manufacturing. Uniquely, the FEA procedure controls both the design and mechanical properties of the devices, and simulates, not only the loading during use, but also the pre-load induced by the donning of both the liner and the socket independently. Through FEA evaluation, detailed information on internal and external tissue loading, which are directly responsible for discomfort and injury, are available. Further, these provide quantitative evidence on the implications of design choices, e.g. : 1) alterations in the design can be used to locally enhance or reduce tissue loading, 2) compliant features can aid in relieving local surface pressure. The proposed methods form a patient-specific, data-driven and repeatable design framework for biomechanical interfaces, and by enabling FEA-based optimization reduces the requirement for repeated patient involvement in the currently manual and iterative design process.

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“…In prosthetics, some patients might require a special, more accurate socket shape while other patients might do fine with the normal quality shape. Presumably, the cost of fabricating a very accurately shaped socket is higher, particularly if the latest technology is used, i.e., additive fabrication techniques [12][13][14][15][16]. One possible means for managing these differences in patient adaptability is to distinguish the minimally adaptable patient by a special rating, for example a rating termed "P-1."…”

Section: Discussionmentioning

confidence: 99%

“…Direct socket fabrication approaches have been pursued in research investigations and potentially have less error than current CAM techniques [12][13][14][15][16]18]. While moving to one of these technologies can potentially overcome shape fabrication error, these technologies are not yet commercially available for prosthetics.…”

Section: Overcoming Errormentioning

confidence: 99%

Assessment technique for computer-aided manufactured sockets

Sanders

Severance

2011

JRRD

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Abstract-This article presents an assessment technique for testing the quality of prosthetic socket fabrication processes at computer-aided manufacturing facilities. The assessment technique is potentially useful to both facilities making sockets and companies marketing manufacturing equipment seeking to assess and improve product quality. To execute the assessment technique, an evaluator fabricates a collection of test models and sockets using the manufacturing suite under evaluation, then measures their shapes using scanning equipment. Overall socket quality is assessed by comparing socket shapes with electronic file (e-file) shapes. To characterize carving performance, model shapes are compared with e-file shapes. To characterize forming performance, socket shapes are compared with model shapes. The mean radial error (MRE), which is the average difference in radii between the two compared shapes, provides insight into sizing quality. Interquartile range (IQR), the range of radial error for the best-matched half of the points on the compared socket surfaces, provides insight into regional shape quality. The source(s) of socket shape error may be pinpointed by separately determining MRE and IQR for carving and forming. The developed assessment technique may provide a useful tool to the prosthetics community and industry to help identify problems and limitations in computer-aided manufacturing and give insight into appropriate modifications to overcome them.

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Double-Wall, Transtibial Prosthetic Socket Fabricated Using Selective Laser Sintering: A Case Study

Cited by 39 publications

References 0 publications

Finite-element analysis to determine effect of monolimb flexibility on structural strength and interaction between residual limb and prosthetic socket

Finite-element analysis to determine effect of monolimb flexibility on structural strength and interaction between residual limb and prosthetic socket

Automated and Data-driven Computational Design of Patient-Specific Biomechanical Interfaces

Assessment technique for computer-aided manufactured sockets

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