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Biodegradable Suture Anchors
Newly developed 'suture anchors' stay strong just long enough until they dissolve in the body.
From Materials Science on G+
Newly developed 'suture anchors' stay strong just long enough until they dissolve in the body.
From Materials Science on G+
New Biodegradable Suture Anchors
When a person has a bad shoulder injury like a torn tendon, surgery is required. The surgeon will use anchor screws for sutures that attach to the bone to do the repair. These anchor screws have to be strong enough to carry the load until the body has a chance to heal. Up to now surgeons have been using materials that need to be left in place or removed after the healing process is over. "Researchers at the Fraunhofer Institute for Manufacturing Technology and Advanced Materials in Bremen, Germany have been working on durable implants that degrade and slowly dissolve into the body for further secretion."
No other joint in the human body is as highly mobile as is the shoulder. However, it is also very sensitive and prone to injury, with athletes being particularly affected. The most common complaints include tendon rupture, which have to be treated surgically. The surgeon fastens the cracks using suture anchors. Such implants used to be made of titanium or non-degradable polymers – with the disadvantages that either they remain in the body even after healing has occurred or doctors have to remove them in a second procedure. ⓐ
The researchers developed anchor screws that are designed to slowly biodegrade while keeping their strength as long as needed. They are made from a metal - ceramic composite and manufactured using a powder metallurgy process.
These materials are to be gradually absorbed by the body while, at the same time, new bone tissue is formed. Ideally, the degree of degradation is adapted to the bone growth so that the degradation of the implant meshes with the bone formation. For this reason, the scientists are developing materials with specifically adjustable degradation. The challenge: The implants have to be mechanically stable enough during the entire healing process so that they are able to fix the bone in place. At the same time, they cannot have any allergenic effects or cause inflammation. The researchers at IFAM are relying on metal-ceramic composites. ⓐ
A metal component based on an iron alloy is being combined with beta-tricalcium phosphate (TCP) as the ceramic component. “Iron alloys corrode slowly and ensure high mechanical strength, while ceramic decomposes quickly, stimulates bone growth and aids the ingrowth of the implant”, Imgrund says to explain the advantages of this material combination. ⓐ (Dr. Philipp Imgrund, manager of the Medical Technology and Life Sciences business field at IFAM.)
Powder injection molding is used to manufacture the material composite due to its ability to produce complex structures cost-effectively and in large numbers. Properties such as density and porosity can be controlled selectively – an important factor, since high density and low porosity result in high mechanical strengths. The process also allows materials, available as powders, to be mixed in any proportion prior to processing. ⓑ
The materials are available as powders and can be mixed in any proportion prior to processing. But what proportion is the right one? In laboratory experiments, the researchers have found the optimum composition of the materials for the suture anchor. The demonstrator consists of 60 percent iron and 40 percent ceramic. “It is important to determine the right amount of ceramics as a function of the powder amount. If the proportion is too high, the material will be brittle. On the other hand, the tricalcium phosphate accelerates the degradation of the implant,” says Imgrund. The researchers have succeeded in doubling the degradation rate from 120 to 240 micrometers per year in the laboratory model. The shoulder anchor would be absorbed by the body within one to two years. ⓐ
ⓐ Press Release, Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM in Bremen
Fewer surgeries with degradable implants
http://www.fraunhofer.de/en/press/research-news/2014/november/fewer-surgeries-with-degradable-implants.html
ⓑ Micro Manufacturing, Injection-molded degradable implants allow for fewer surgeries
http://www.micromanufacturing.com/content/injection-molded-degradable-implants-allow-fewer-surgeries
Image: The demonstrator for a suture anchor made of iron-tricalcium phosphate (FE-TCP)is only slightly larger than a match head. © Fraunhofer IFAM
When a person has a bad shoulder injury like a torn tendon, surgery is required. The surgeon will use anchor screws for sutures that attach to the bone to do the repair. These anchor screws have to be strong enough to carry the load until the body has a chance to heal. Up to now surgeons have been using materials that need to be left in place or removed after the healing process is over. "Researchers at the Fraunhofer Institute for Manufacturing Technology and Advanced Materials in Bremen, Germany have been working on durable implants that degrade and slowly dissolve into the body for further secretion."
No other joint in the human body is as highly mobile as is the shoulder. However, it is also very sensitive and prone to injury, with athletes being particularly affected. The most common complaints include tendon rupture, which have to be treated surgically. The surgeon fastens the cracks using suture anchors. Such implants used to be made of titanium or non-degradable polymers – with the disadvantages that either they remain in the body even after healing has occurred or doctors have to remove them in a second procedure. ⓐ
The researchers developed anchor screws that are designed to slowly biodegrade while keeping their strength as long as needed. They are made from a metal - ceramic composite and manufactured using a powder metallurgy process.
These materials are to be gradually absorbed by the body while, at the same time, new bone tissue is formed. Ideally, the degree of degradation is adapted to the bone growth so that the degradation of the implant meshes with the bone formation. For this reason, the scientists are developing materials with specifically adjustable degradation. The challenge: The implants have to be mechanically stable enough during the entire healing process so that they are able to fix the bone in place. At the same time, they cannot have any allergenic effects or cause inflammation. The researchers at IFAM are relying on metal-ceramic composites. ⓐ
A metal component based on an iron alloy is being combined with beta-tricalcium phosphate (TCP) as the ceramic component. “Iron alloys corrode slowly and ensure high mechanical strength, while ceramic decomposes quickly, stimulates bone growth and aids the ingrowth of the implant”, Imgrund says to explain the advantages of this material combination. ⓐ (Dr. Philipp Imgrund, manager of the Medical Technology and Life Sciences business field at IFAM.)
Powder injection molding is used to manufacture the material composite due to its ability to produce complex structures cost-effectively and in large numbers. Properties such as density and porosity can be controlled selectively – an important factor, since high density and low porosity result in high mechanical strengths. The process also allows materials, available as powders, to be mixed in any proportion prior to processing. ⓑ
The materials are available as powders and can be mixed in any proportion prior to processing. But what proportion is the right one? In laboratory experiments, the researchers have found the optimum composition of the materials for the suture anchor. The demonstrator consists of 60 percent iron and 40 percent ceramic. “It is important to determine the right amount of ceramics as a function of the powder amount. If the proportion is too high, the material will be brittle. On the other hand, the tricalcium phosphate accelerates the degradation of the implant,” says Imgrund. The researchers have succeeded in doubling the degradation rate from 120 to 240 micrometers per year in the laboratory model. The shoulder anchor would be absorbed by the body within one to two years. ⓐ
ⓐ Press Release, Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM in Bremen
Fewer surgeries with degradable implants
http://www.fraunhofer.de/en/press/research-news/2014/november/fewer-surgeries-with-degradable-implants.html
ⓑ Micro Manufacturing, Injection-molded degradable implants allow for fewer surgeries
http://www.micromanufacturing.com/content/injection-molded-degradable-implants-allow-fewer-surgeries
Image: The demonstrator for a suture anchor made of iron-tricalcium phosphate (FE-TCP)is only slightly larger than a match head. © Fraunhofer IFAM
View 6 previous comments
Michelle, as a materials engineer I have always been interested in what properties of metal make a good bell or wind chime.
It is a complicated subject and I am just learning.
Titanium rods used in bone splints do sound unique, light and effervescent. And they do make for interesting nerdlike conversation starters.Nov 15, 2014
+Gary Ray R, my ankle surgeon used those to graft, reconstruct, and reattach my anterior talofibular ligament (ATFL). Three surgeries later (first one was botched by a different ortho), my ankle is stronger than the other one! Btw, how uniquely creative to make wind chimes from a painful injury... a much more pleasant reminder :)Nov 16, 2014
Surgeon tells me I will eventually crap the staples out.
My dental tech trade training told me never to make surgical appliances out of anything bio degradable. Titanium rivals gold for "inertness".
How things change... ..Nov 15, 2014- +Peter Barrett yeah Titanium (mostly alloys) are used quite a bit because that first corrosion layer acts as a protective shield against further deterioration. A company I worked for made Titanium covers for artificial hearts, amongst other things. I remember them because they were fairly easy to manufacture compared to aerospace parts. Basically a casting process, a few heat treatments, and then off to the machine shop for all the detail.
This powder cast method is pretty cool and I bet it will help a lot in determining how fast these little guys dissapear.Nov 15, 2014 
+Gary Ray R Those kind of nerdy conversations always peak my interest- even in areas where I don't have much in way of knowledge. :-)
Nov 15, 2014
Fine screw! Pleasure to look at!Nov 16, 2014
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