Featured Research

from universities, journals, and other organizations

Alloy With "Memory" Helps Bones Heal Faster And More Reliably

Date:
May 24, 2000
Source:
Ohio State University
Summary:
A metal wire that "remembers" its shape may be ideal for helping a broken bone heal faster and more reliably.

COLUMBUS, Ohio - A metal wire that "remembers" its shape may be ideal for helping a broken bone heal faster and more reliably.

Related Articles


Researchers compared Nitinol - a nickel and titanium alloy - to stainless steel in an experiment designed to see which metal worked best on a simulated broken bone. Where the stainless steel wire lost tension during the simulation, the Nitinol kept a continuous pull. Loss of tension could cause a bone to heal improperly.

"Metals like Nitinol remember their original shape," said Alan Litsky, an associate professor of orthopaedics and biomedical engineering at Ohio State University. "This shape 'memory' can be used to help compress broken bones, which could mean a quicker healing time, and a better fusion of the bone."

Litsky will present his findings May 20 at the World Biomaterials Congress in Kamuela, Hawaii.

One common way surgeons treat certain fractures is to tie wire around the affected bone in order to pull the fractured pieces together. The problem is that stainless steel - the most common metal used in these wires - tends to loosen over time as the metal slowly migrates through the bone. This reduces the amount of pressure applied to the fracture and can result in poor healing.

Nitinol, if it is stretched before being wrapped around a fractured bone, resists loosening because it remembers its original shape. This "memory" allows the wire to continue compressing the bone even after it starts to be absorbed by the bone.

Nitinol's shape can be changed below a certain temperature; it then pops back into its original shape when heated. To fix a fracture, Nitinol is cooled, stretched and wrapped around the broken bone. As it warms to body temperature, the wire "remembers" its original length. It tightens around the bone, and begins to compress the fracture to a greater extent than could be achieved by simply tightening the wire.

In this study, the researchers used cylindrical tubes to represent bones. The tubes were connected to a hydraulic system that could change the position of the tubes to simulate what would happen during a six-week fracture healing period. In separate experiments, the researchers wrapped the cylinders with stainless steel wire and with Nitinol to compare their effectiveness at holding the "bones" together with proper compression.

The Nitinol wire was stretched to 108 percent of its length before it was wrapped around the cylinders. It was then heated. When the researchers slowly moved the cylinders together to simulate what would happen as the wire migrated into the bone, the wire tightened. Nitinol was still able to maintain nearly the same level of compression between the cylinders.

The researchers performed the same experiment with stainless steel wire. As the cylinders began moving toward each other, the stainless steel "immediately lost its ability to compress the fracture," Litsky said. As bone heals, stainless steel tends to loosen, losing its ability to place pressure on the bone.

"Stainless steel will hold things where they were, while Nitinol will push the pieces of a broken bone together," Litsky said. "If you use a stainless steel wire and something loosens, the compression on the fracture is lost."

When using Nitinol to repair a broken bone, a surgeon would flush the fracture site with water slightly cooler than body temperature, then wrap pre-stretched Nitinol wire around the site of the break. After the wire warmed, it would attempt to regain its original shape, and then continuously push the bone back together.

"The key with Nitinol wire is its ability to achieve and maintain a high level of compression on the bone while it heals," Litsky said.

Litsky conducted the research in the Orthopaedic BioMaterials Laboratory at Ohio State with Todd Ritzman, a student in Ohio State's College of Medicine and Public Health; Brian Sears of Grant Hospital in Columbus; and Ajay Seth, an orthopaedic resident at Ohio State.


Story Source:

The above story is based on materials provided by Ohio State University. Note: Materials may be edited for content and length.


Cite This Page:

Ohio State University. "Alloy With "Memory" Helps Bones Heal Faster And More Reliably." ScienceDaily. ScienceDaily, 24 May 2000. <www.sciencedaily.com/releases/2000/05/000522084135.htm>.
Ohio State University. (2000, May 24). Alloy With "Memory" Helps Bones Heal Faster And More Reliably. ScienceDaily. Retrieved January 31, 2015 from www.sciencedaily.com/releases/2000/05/000522084135.htm
Ohio State University. "Alloy With "Memory" Helps Bones Heal Faster And More Reliably." ScienceDaily. www.sciencedaily.com/releases/2000/05/000522084135.htm (accessed January 31, 2015).

Share This


More From ScienceDaily



More Health & Medicine News

Saturday, January 31, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

CDC: Get Vaccinated for Measles

CDC: Get Vaccinated for Measles

Reuters - US Online Video (Jan. 30, 2015) The CDC is urging people to get vaccinated for measles amid an outbreak that began at Disneyland and has now infected more than 90 people. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Obama To Outline New Plan For Personalized Medicine

Obama To Outline New Plan For Personalized Medicine

Newsy (Jan. 30, 2015) President Obama is expected to speak with drugmakers Friday about his Precision Medicine Initiative first introduced last week. Video provided by Newsy
Powered by NewsLook.com
NFL Concussions Down; Still on Parents' Minds

NFL Concussions Down; Still on Parents' Minds

AP (Jan. 30, 2015) The NFL announced this week that the number of game concussions dropped by a quarter over last season. Still, the dangers of the sport still weigh on players, and parents&apos; minds. (Jan. 30) Video provided by AP
Powered by NewsLook.com
U.S. Wants to Analyze DNA from 1 Million People

U.S. Wants to Analyze DNA from 1 Million People

Reuters - US Online Video (Jan. 30, 2015) The U.S. has proposed analyzing genetic information from more than 1 million American volunteers to learn how genetic variants affect health and disease. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins