Medical Design Briefs - October 2022 - 16

Additive Manufacturing:
Creating the
Next Generation
of Orthopedic
Implants
A
16
dditive Manufacturing (AM) is an exciting technology
being explored for use in the medical device landscape.
From improved patient outcomes to point-ofcare
manufacturing, 3D printing offers a host of
benefits that promise to transform the orthopedic
implant industry once fully implemented. For medical companies
to leverage this novel manufacturing technology, extensive materials
testing will be needed in order to validate new processes and
prove that their products are functionally comparable (or superior
to) those made with traditional processes. Adding to the complexity,
this application currently exists in a dynamic regulatory
environment where the industry is still debating best practices.
Companies seeking to explore this space will need to implement a
highly adaptable materials testing program in order to realize the
full potential of additively manufactured orthopedic implants.
Disadvantages of Traditional Manufacturing
The geometry of anatomical structures is exceedingly complex,
and traditional subtractive manufacturing is severely
limited in the geometries it can produce, as well as the number
of pieces of equipment required to make an implant.
Furthermore, the time required for machining can be significant,
especially when working with harder metals such as
titanium, which is frequently used for orthopedic implants
due to its mechanical properties and biocompatibility. Technological
improvements in traditional manufacturing processes
such as computer numerical control (CNC) machining
remove operator error and allow for a wider range of
geometries with a single machine, but still fail to address the
medical shortcomings of traditionally produced implants.
Casting requires appropriate tooling and jigs to pour molten
materials into - a process that can produce more complex
geometries but is often cost prohibitive due to the capital
required for the tooling and jigs. For this reason, many
implants are only available in discrete sizes that are based
on historical patient data representing the average groupings
of patient anatomical geometry. This sizing model is detrimental
to patient outcomes because physicians often need to
remove more bone to ensure a proper fit. A study performed
using finite element analysis (FEA) and the comparison of
traditionally and custom designed AM implants found that
the amount of bone removal could be reduced by 40 percent
when using custom-sized implants.1
Although orthopedic implants are often intended to be in
use for 30+ years, poorly sized implants can result in unexpected
stress concentrations from daily wear and tear, reducing the
total life of the implant. The revisional surgery required to remove
and replace damaged or broken implants is costly and
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Medical Design Briefs, October 2022
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Medical Design Briefs - October 2022

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