Item — HN Reader

> “Then I insert a rod — we call it a nail or a rod — that goes inside the bone. The rod is magnetic and it has gears. Then there’s an external device that communicates with the nail. And over time, little by little, it lengthens out the nail.” The lengthening happens gradually. “We usually say about a millimeter a day, until they get to their desired height.”

The "external device that communicates with the nail" part should perk up hacker ears, with various motivations. o_O

2 comments

If your bones get unusually hot, they may be mining Bitcoin for North Korea.

I’ve had this surgery 4 times, and the latest was 2019 where I used this “external device”. It’s using magnetism to manipulate the nail. You place it over the right spot on your leg and it makes ‘back and forth, back and forth’ type noises.

Definitely no internal computers involved.

Can you explain where the "extra" bone matter comes from?

The article said the bone gets cut and it wasn't clear if it get cut through and then two halves are shifted away from each other or the cut is more on an incision into the bone and the the bone just gets stretched by this device.

Broken is cut/chiseled in half. Then the nail is inserted into the bone (my femur) up near the top.

The "extra" bone comes from the body's natural healing mechanism. If you pull the bone apart slowly enough, the body forms a continuous connection of new bone in the gap. I did 1mm a day, I think.

What actually happens is that the new bone material is initially gelatinous, so as you lengthen the gap, the gelatinous material is elongated and doesn't harden (at least not in the in the middle of the gap).

The rate of hardening and the rate of gap extension should be optimized to create the best bone quality. I wonder if then science to find the correct balance has been done.

Thanks for sharing! So the article stretched with "device that communicates".