Tag Archives: hip implant

My mother is a cyborg

About 20 or 25 years ago there was a robot/cyborg/ etc. show at the local art gallery. The curators of the show noted that people with hip and/or knee replacements, pacemakers, deep brain stimulators, etc. were cyborgs. It was along time ago and I wasn’t sure I remembered rightly so I checked and found this in a Wikipedia essay,

A cyborg, short for “cybernetic organism”, is a being with both biological and artificial (e.g. electronic, mechanical or robotic) parts. The term was coined in 1960 when Manfred Clynes and Nathan S. Kline used it in an article about the advantages of self-regulating human-machine systems in outer space.D. S. Halacy’s Cyborg: Evolution of the Superman in 1965 featured an introduction which spoke of a “new frontier” that was “not merely space, but more profoundly the relationship between ‘inner space’ to ‘outer space’ – a bridge…between mind and matter.”

My mother became a cyborg five years ago when she had a hip replacement. I don’t believe that I will ever share that information with her; she simply wouldn’t want to know.

Since her operation, I’ve become somewhat interested in hip replacements. From the April 19, 2012 news item by Anne Trafton on Nanowerk about research at MIT (Massachusetts Institute of Technology),

Every year, more than a million Americans receive an artificial hip or knee prosthesis. Such implants are designed to last many years, but in about 17 percent of patients who receive a total joint replacement, the implant eventually loosens and has to be replaced early, which can cause dangerous complications for elderly patients.

To help minimize these burdensome operations, a team of MIT chemical engineers has developed a new coating for implants that could help them better adhere to the patient’s bone, preventing premature failure.

The coating, which induces the body’s own cells to produce bone that fixes the implant in place, could also be used to help heal fractures and to improve dental implants, according to Hammond and lead author Nisarg Shah, a graduate student in Hammond’s [Paula Hammond, senior author] lab.

Here’s what can happen to an artificial hip, (from the April 19, 2012 news release on the MIT website),

Artificial hips consist of a metal ball on a stem, connecting the pelvis and femur. The ball rotates within a plastic cup attached to the inside of the hip socket. Similarly, artificial knees consist of plates and a stem that enable movement of the femur and tibia. To secure the implant, surgeons use bone cement, a polymer that resembles glass when hardened. In some cases, this cement ends up cracking and the implant detaches from the bone, causing chronic pain and loss of mobility for the patient.

“Typically, in such a case, the implant is removed and replaced, which causes tremendous secondary tissue loss in the patient that wouldn’t have happened if the implant hadn’t failed,” Shah says. “Our idea is to prevent failure by coating these implants with materials that can induce native bone that is generated within the body. That bone grows into the implant and helps fix it in place.”

The new coating consists of a very thin film, ranging from 100 nanometers to one micron, composed of layers of materials that help promote rapid bone growth. One of the materials, hydroxyapatite, is a natural component of bone, made of calcium and phosphate. This material attracts mesenchymal stem cells from the bone marrow and provides an interface for the formation of new bone. The other layer releases a growth factor that stimulates mesenchymal stem cells to transform into bone-producing cells called osteoblasts.

The Hammond lab has kindly made an image of  the hydroxyapatite nanoparticles,

Hydroxyapatite nanoparticles are incorporated into multilayer coatings for faster bone tissue growth. Image courtesy of the Hammond Lab

I hope that this improved method for hip implants will be in hospitals in foreseeable future.

ETA April 20, 2012: You can check out Dexter Johnson’s April 19, 2012 posting on Nanoclast (on the Institute of Electrical and Electronics Engineers [IEEE] website).