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So far, in the case of fractures, doctors have used implants made of steel and titanium, which must be removed after healing. In order to avoid heavy interventions for patients, researchers are studying a bone substitute that can be completely degraded in the body. To this end, a material combination of metal and ceramic is being used.
There are no other joints in the human body that are as highly mobile as the shoulders. However, it is also very sensitive and easily injured, and athletes are especially affected. The most common complaints include tendon rupture, which must be treated surgically. The surgeon uses suture anchors to fix the cracks. Such implants used to be made of titanium or non-degradable polymers-the disadvantage is that they either remain in the body after healing, or the doctor must remove them in a second operation. To avoid this, researchers at the Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM in Bremen have developed load-bearing, biodegradable implants that are completely degradable in the body. In the first step, they used powder injection molding to create a suture anchor that can be used as a demonstrator. Researchers will show it at the COMPAMED trade fair in Düsseldorf from November 12th to 14th.
Calcium phosphate stimulates the bone healing process
"Through the implant, the severed tendons can be anchored to the bone until they grow again. Since the function of the fixation element is satisfied after the healing process, the body no longer needs it. If the implant or prosthesis wears out, it needs to be as much as possible Resistance—for example in artificial hip joints—metal alloys such as titanium will certainly continue to be used. However, there are other requirements for plates, screws, pins and nails that should not be left in the body," said Dr. Philipp Imgrund, IFAM's medical technology and life sciences business area manager. In the "DegraLast" project, IFAM and Fraunhofer ILT, Biomedical Engineering IBMT and IGB of Interface Engineering and Biotechnology have established a material and technology platform to produce biodegradable bone implants for trauma surgery and orthopedics. These materials will gradually be used by the body. Absorption, while forming new bone tissue. Ideally, the degree of degradation is adapted to bone growth so that the degradation of the implant coincides with bone formation. For this reason, scientists are developing materials with special adjustable degradation. Challenge: Throughout the healing process, implants must have sufficient mechanical stability so that they can hold the bones in place. At the same time, they will not produce any allergic effects or cause inflammation. IFAM researchers rely on cermet composites. A metal component based on ferroalloy is combined with β-tricalcium phosphate (TCP) as a ceramic component. “Ferroalloys corrode slowly and ensure high mechanical strength, while ceramics decompose rapidly, which stimulates bone growth and helps implant orientation. In-growth," Imgrund said when explaining the advantages of this material combination.
In order to be able to manufacture this material composite, the researchers turned to the powder injection molding process. It provides the ability to mass-produce complex structures cost-effectively. Properties such as density and porosity can be selectively controlled-this is an important factor because high density and low porosity lead to high mechanical strength. Another advantage: these materials are provided in powder form and can be mixed in any ratio before processing. But what is the correct ratio? In laboratory experiments, the researchers found the best composition of the suture anchor material. The demonstrator is composed of 60% iron and 40% ceramic. "It is important to determine the appropriate amount of ceramic based on the amount of powder. If the ratio is too high, the material will become brittle. On the other hand, tricalcium phosphate will accelerate the degradation of the implant," Imgrund said. The researchers successfully integrated the laboratory model The degradation rate has increased from 120 microns to 240 microns per year. The shoulder anchor will be absorbed by the body within one to two years.
Although molding processes such as powder injection molding are particularly suitable for mass use as fixation elements for standard implants, additive manufacturing methods are used to produce single implants—for example, for bone replacement in the skull region—or those with a clear pore structure. Implants. Researchers from ILT are also participating in the project, and they are using selective laser melting (SLM) to produce implants made of magnesium alloy. In order to ensure the safety of the new composite material from the beginning, colleagues from the "DegraLast" project of IGB are establishing a cell-based in vitro test system to analyze the ingrowth behavior of bones. IBMT scientists are working on an in-vivo monitoring system that can monitor and record the degradation behavior of implants in the human body. Further exploration of new materials for better, stronger and cheaper dental implants. Citation provided by Fraunhofer-Gesellschaft: Biodegradable implants reduce the number of operations (2014, November 4), December 14, 2021 Retrieved from https://phys.org/news/2014-11-surgeries-degradable-implants.html This document is protected by copyright. Except for any fair transaction for private learning or research purposes, no part may be copied without written permission. The content is for reference only.
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