Ankles Away

Ankles Away

Ankles Away

Science, technology, and life.
Nov. 19 2008 7:57 AM

Ankles Away

Looks like I missed a joint.

A couple of months ago, I wrote about the artificial parts we've been putting into people: hips, knees, shoulders, spinal discs, and elbows. U.S. government stats show more than 1 million such replacements per year. Piece by piece, we're mechanizing the body.

William Saletan William Saletan

Will Saletan writes about politics, science, technology, and other stuff for Slate. He’s the author of Bearing Right.

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Next up: ankles.

Lauran Neergard of the AP has the story . There's a healthy (actually, an unhealthy) market for new ankles: More than 200,000 patients go to doctors for ankle pain every year. The prevailing surgical option is to fuse the ankle bones, which gets rid of the friction, and therefore the pain, but skews the way you move your foot. That, in turn, increases the strain on other foot joints, causing more pain and more fusions.

So why hasn't ankle replacement become as popular as hip or knee replacement? Because ankles are smaller and have to shoulder (so to speak) more stress. The original generation of artificial ankles broke down under normal wear and tear. A new generation is just now taking off. They cost up to $50,000 but are designed to operate more like a natural ankle, which would avoid the downstream damage associated with fusion. Neergard explains how they work:

Each model is slightly different but consists of two attached parts. Surgeons drill a tunnel into the lower leg bone and slide in the stem of the artificial joint. A bottom piece connects to the top of the foot. Thin plastic hooked to one side functions as cartilage. Bone then grows into the implant, holding it in place. In Europe, doctors also can use a similar but three-piece artificial ankle, where the plastic cushion is free-floating.

So the artificial cushion relieves day-to-day strains on the ankle, while the body, through bone growth, adopts the new mechanism as its own. Biology absorbs technology. Very cool. Let's hope it works.