Computer-Aided Design and 3D Printing in Prosthetics

Computer-aided design (CAD) and additive manufacturing (3D printing) bring digital workflows to the design and production of prosthetic and orthotic devices. A limb or body region is captured by scanning, a device is modelled and modified on screen, and it is then produced by computer-controlled manufacturing, either by carving a model for traditional fabrication (CAD/CAM) or by building the device directly layer by layer through 3D printing. These methods promise greater reproducibility, customization and, in some settings, lower cost.

Definition

Computer-aided design and 3D printing in prosthetics is the use of digital modelling (CAD) together with computer-controlled or additive manufacturing to design and fabricate prosthetic and orthotic devices, replacing or supplementing manual casting and hand fabrication.

Scope

This topic covers the digital design-and-fabrication pipeline as it applies to prosthetics and orthotics: scanning, CAD modelling, computer-aided manufacturing, and additive manufacturing, together with their design parameters and trade-offs. It is reference material on the technology and its considerations, not a manufacturing protocol or clinical guidance for producing a device for an individual.

Core questions

• How does a digital design-and-fabrication pipeline work in prosthetics and orthotics?
• How do CAD/CAM and additive manufacturing differ?
• What design parameters affect the strength and quality of a 3D-printed device?
• What are the potential benefits and limitations of digital fabrication?

Key concepts

• Computer-aided design (CAD)
• Computer-aided manufacturing (CAM)
• Additive manufacturing (3D printing)
• Surface scanning and digital shape capture
• Fused filament fabrication
• Infill and layer parameters
• Reproducibility and customization

Mechanisms

A digital workflow typically begins by capturing the shape of the limb or body region with a surface scanner, producing a three-dimensional model. The clinician or engineer modifies this model in CAD software to create the device geometry, applying shape rectifications analogous to those done by hand on a plaster cast. The model is then realized either by computer-aided manufacturing, which carves a positive model for conventional moulding, or by additive manufacturing, which builds the device directly by depositing material layer upon layer. In printed parts, process parameters such as material choice, layer orientation and infill density influence mechanical strength, so these settings are central to whether a printed device can withstand functional loads.

Clinical relevance

Digital design and additive manufacturing are reshaping how prosthetic and orthotic devices are produced and offer reproducible, customizable workflows that are an active area of research and practice. This entry describes the technology and its engineering considerations as reference material; it does not provide instructions for fabricating a device or guidance for selecting a manufacturing method for an individual patient.

Evidence & guidelines

The evidence base is dominated by engineering studies and reviews. Reviews of polymer-based additive manufacturing describe growing adoption and the range of materials and processes in use, while experimental studies, such as Campbell and colleagues (2018), examine how print parameters like infill percentage affect the strength of 3D-printed transtibial sockets, highlighting that mechanical adequacy depends strongly on how a device is printed.

History

Computer-aided design and manufacturing entered prosthetics and orthotics from the 1980s onward as a way to digitize the shaping of sockets and orthoses that had traditionally been done by hand on plaster casts. The later spread of accessible 3D printing, particularly fused filament fabrication, extended the digital pipeline to direct production of devices and spurred research into materials, print parameters and the strength of printed components.

Seminal works

• campbell-2018
• sakib-2023

Frequently asked questions

What is the difference between CAD/CAM and 3D printing in prosthetics?

In CAD/CAM, a digital model is used to machine a positive model for conventional fabrication, whereas in 3D printing (additive manufacturing) the device itself is built directly by depositing material layer by layer.

Does how a socket is 3D-printed affect its strength?

Yes. Process parameters such as the material, the orientation of printed layers and the infill density influence the mechanical strength of a printed device, so these settings matter for whether it can withstand functional loads.