The Development of a Rapid Prototyping Prosthetic Socket Coated with a Resin Layer for Transtibial Amputees

Abstract

This article proposes a type of transtibial socket composed of an inner layer fabricated by a rapid prototyping (RP) machine and an outer layer coated with unsaturated polyester resin. This work integrates contemporary technologies including a handheld scanner and CAD systems, to design a thin primary socket shape and then manufactures the socket using a fused deposition-modeling machine. To prevent breakage caused by the layer-based forming process and to reinforce flexural strength, the current research coats the preliminary RP socket with a layer of unsaturated polyester resin. After shaping the proximal brim of the resin-reinforced RP socket to match the specific stump, this study assembles and aligns a shank and a prosthetic foot to form a prosthesis set. After completing a trial safety walk wearing the prosthesis, which is satisfactory to the amputee and a registered prosthetist, this research measures interface pressures between the stump and the resin-reinforced RP socket. Experiment results demonstrate that the resin-reinforced RP socket is applicable for transtibial amputees. In addition to strengthening the FDM socket and producing consistent socket fit, this study also demonstrates a feasible procedure that employs current technologies to design and manufacture transtibial sockets without plaster moulds.

Additive manufacturing of custom orthoses and prostheses—A review

“…A group at National Cheng Kung University studied coating FDM sockets with a polyester resin layer, as shown in Fig. 13, to increase the flexural strength [45,46]. This group also developed a system which used a vacuum forming tool to capture the geometry of the residual limb under a controlled negative pressure and AM was used to fabricate a positive mold to represent the residual limb [48].…”

“…Leddy et al [57] used additive manufactured molds to fabricate components for prosthetic hands with multiple and composite materials to achieve light weight and high stiffness. an AM system [11,43], uneconomic throughput and material cost [12,15], and limited material strength [41,46].…”

Assessment of a Virtual Functional Prototyping Process for the Rapid Manufacture of Passive-Dynamic Ankle-Foot Orthoses

“…FDM techniques have successfully been used in biomedical applications including for prosthetic sockets [23,24], patient-specific models used for surgical planning [25], and the development of biocompatible, customized implants [26]. FDM manufacturing has been shown to produce parts with excellent and repeatable dimensional accuracy [27]; however, the mechanical properties of fabricated parts are sensitive to build parameters including orientation and layer thickness [28][29][30], and, consequently, manufacturer provided material properties are often inaccurate when fabricating unique parts.…”

Partial Foot Amputation, Finite Element Analysis of Foot and Manufacturing of Prosthtic Sockets: A Review

“…Examples of AM prosthetic sockets, made by (a) Hertbert et al [24] (b) Roger et al [22] (c) Hsu et al [25] (d) Sengeh et al [26] …”