Passage
3D-PRINTED PROSTHETICS
(1)
Once a rarely used curiosity confined to a few research labs, 1 the use of 3D-printed prosthetics has grown dramatically in number and variety since the introduction of the first affordable printed 2 hand—a model its makers called the OpenGrip—more than a decade ago. Printed prosthetics already play a real part in almost every branch of rehabilitation 3 but this part is still only beginning to grow. Custom fittings, 4 such as tailored sockets, jointed fingers, and lightweight forearm cradles, are in growing demand among patients of every age. Some can still be carved by hand from 5 wood, this is slow and leaves little room for later adjustment. 6 Devices can be machined from solid titanium but costs are very high and output small.
(2)
7 Much larger quantities can be turned out by injection molding, but the limbs produced are hard to fit precisely and they lack the fine, patient-specific adjustments that a comfortable prosthesis requires.
(3)
[1] By contrast, 8 sockets match a patient's exact anatomy can be printed layer by layer from a single digital scan of the residual limb. [2] The printers work as tireless little workshops, building hollow, complex shapes or forms that cannot be produced by casting or milling. [3] Currently, clinics around the world are testing 9 whether these printed sockets can be used for everyday wear. [4] One machine can finish a wearable socket overnight, and the material it consumes is relatively cheap. 10
(4)
One advantage of printing prosthetics is that it wastes far less raw material than carving a limb from a solid block does. 11
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12 The main disadvantage of printing prosthetic limbs is that it takes time to design and certify each new model, that a finished part cannot be delivered until the scan has been processed, and that the plastic itself may weaken, for example, as a printed layer bonds imperfectly to the one beneath, 13 they may crack under the stress of daily walking. Notwithstanding these, the prosthetics industry is expanding quickly, and it is expected that demand for affordable devices will soon exceed 14 its ability to supply these. Printed prosthetics 15 can possibly offer a low-cost alternative for the many people who need them.
