Manufacturing a human heel in titanium via 3D printing

3D printing continues to find new uses as more people get familiar with the capabilities of this relatively new manufacturing tool. Professor Peter Choong at Melbourne's St Vincent's Hospital proved the adage “chance favours the prepared”. His patient faced losing a foot due to a cancerous heel, so he came up with the idea of a 3D-printed alternative. He engaged medical device company Anatomics to design the implant. The CSIRO's Lab 22 was contacted due to its capability in 3D printing and, within a week, a foot-saving replacement was used in surgery — a world first.

Using engineering principles and computer-assisted design, Anatomics manipulated the computed tomography data of the patient's healthy heel to design a device to include muscle attachment points to support the new heel once implanted, internal structures to handle the forces of an adult heel, and porosity to reduce implant weight and facilitate tissue integration.

The CSIRO manufactured the design in its Arcam A1 printer. Using titanium Ti6Al4V powder, the printer produced the device overnight. The CSIRO and Anatomics cleaned and prepared the device for surgery. The collaborative team made several prototypes, refining the designs for form, fit and function. The final version was implanted about 24 hours after manufacturing.

There are a number of learning outcomes from this endeavour. The patient was able to keep his foot, which otherwise would have been amputated. Quality of life was preserved. The state of the art has been advanced and, following the success, more challenging applications can be undertaken with lower risk. And from the manufacturing perspective, investment in digital file manipulation, lower-cost materials and capable equipment will make the technology more accessible.