(Press-News.org)
Customized 3D-printed medical implants are becoming more common, and a new study has taken this technology to the next level. Researchers at Naton Biotechnology have developed the world’s first laser 3D-printed total knee implant, which has received official approval from China’s National Medical Products Administration as an innovative medical device.
The study focused on improving the strength and consistency of cobalt-chromium-molybdenum (CoCrMo) alloy implants made using laser powder bed fusion (LPBF), a 3D printing process. The team discovered and corrected inconsistencies in the structure of the material by optimizing heat treatment, ensuring the final implants are stronger, more reliable, and safer for patients.
This research provides key insights into how 3D printing affects metal implants and lays the foundation for better quality control in orthopedic manufacturing, helping to advance the future of customized medical implants.
This research was led by Professor Changhui Song from South China University of Technology and Professor Jia-Kuo Yu from Beijing Tsinghua Changgung Hospital as co-corresponding authors. The study was conducted in collaboration with Senior Engineer Renyao Li from Naton Biotechnology (Beijing) Co., Ltd and other members of the team.
The Problem: Uneven Strength in 3D-Printed Metal Implants
The layer-by-layer manufacturing process of CoCrMo, a widely used implant material, occurs at extremely high cooling rates (~10⁵–10⁶ K/s). This rapid solidification often leads to anisotropy, meaning the material's properties vary depending on the direction of force. The main causes include columnar grain structures, porosity, and residual stress, all of which are inherent to additive manufacturing.
While extensive research has been conducted on LPBF-fabricated CoCrMo alloys, most studies have only examined their performance in a single direction, overlooking how anisotropy affects overall durability. However, implants inside the human body must withstand forces from multiple directions. Then, if the material's strength is inconsistent, weak spots can develop, increasing the risk of breakage or failure.
In mechanical tests, CoCrMo samples stretched significantly more in one direction (19.1% elongation) than in another (9.3% elongation)—a disparity of over 100%. This inconsistency makes the material unreliable for long-term medical use, as implants must perform uniformly and safely under everyday stresses.
The Solution: A New Heat Treatment Process
The team found that a two-step heat treatment process significantly improved the uniformity of the metal’s structure and strength. The process included:
Solution Treatment – Heating the material to 1150°C, holding it for an hour, and then rapidly cooling it in water. This helped restructure the uneven metal grains.
Annealing – Reheating the material to 450°C for 30 minutes and then cooling it again. This step refined the grain structure and further balanced the material's properties.
As a result, the metal’s strength and flexibility became nearly identical in all directions. The ultimate tensile strength reached 906.1 MPa and 879.2 MPa, while elongation values balanced at 20.2% and 17.9%, making the material stronger and more reliable for medical use.
The Future: Improving Durability and Biocompatibility
With this breakthrough, scientists are now looking at surface treatments to further enhance the wear resistance and biocompatibility of implants. Methods like shot peening (where tiny metal beads are blasted onto the surface) and ultrasonic peening could improve the fatigue resistance of implants, helping them last longer under daily stress. These next-generation treatments could make 3D-printed joint implants even more durable and widely used in clinical settings.
The Impact: A Safer Future for Medical Implants
This research offers new insights into how to improve 3D-printed metal implants, making them safer and more durable for patients. By addressing uneven strength and material quality, this breakthrough lays the foundation for better orthopedic implants, particularly for joint replacements.
The findings were recently published in the international journal Materials Futures, further advancing research in medical-grade additive manufacturing.
Reference:
Lijin Dai, Changhui Song, Houxiong Fu, Hongyi Chen, Zhongwei Yan, Zibin Liu, Renyao Li, Anming Wang, Yongqiang Yang, Jia-Kuo Yu. Recrystallization induced by heat treatment regulates the anisotropic behavior of CoCrMo alloys fabricated by laser powder bed fusion[J]. Materials Futures. DOI: 10.1088/2752-5724/adb50a
END
The South by Southwest (SXSW) Conference and Festivals — a renowned convergence of pioneers, storytellers, and global visionaries — will take place this year from March 7-15 in Austin, Texas, bringing together a vibrant mix of ideas and innovations. Once again, UC San Diego will take center stage, showcasing cutting-edge research, transformative discussions on critical global challenges and a film premiere.
“UC San Diego’s participation in the 2025 South by Southwest Conference and Festivals reinforces our institution’s passion for interdisciplinary ...
On the shores of Lake Tahoe at Emerald Bay State Park grows what some consider to be the most iconic old-growth forest in the Lake Tahoe Basin. Giant ponderosa pines — some of the last remaining in the area — share space with at least 13 other tree species.
Yet despite its high conservation value and proximity to severely burned forests, the Emerald Point stand has not been managed to reduce its risk to drought or catastrophic wildfire. The fire-adapted forest has also not experienced fire for at least 120 years. This has led to massive increases in forest density, fuels, and insect- and drought-driven mortality.
A fire ...
SAN ANTONIO — March 3, 2025 —Researchers at Southwest Research Institute (SwRI) and the University of Michigan (U-M) have published a new study showing an advanced new methane flare burner, created with additive manufacturing and machine learning, eliminates 98% of methane vented during oil production. The burner was designed by U-M engineering researchers and tested at SwRI.
Oil producers can generate methane during oil production and typically use flare stacks to burn off this gas. However, wind blowing across conventional ...
Dental implants used to replace single teeth continue to function well after several decades, according to a study from the University of Gothenburg, Sweden. After nearly forty years, all examined implants were still in place and fully functional.
The study is the longest follow-up study of single dental implants in the world and is based on a follow-up of a small group of patients who received single implants to replace missing teeth between 1982 and 1985.
The implants are a result of research conducted by Professor Per-Ingvar Brånemark ...
When a droplet of water falls on a hot pan, it dances across the surface, skimming on a thin layer of steam like a tiny hovercraft; this is known as the Leidenfrost effect. But now, researchers know what happens when a hot droplet falls on a cool surface. These new findings, publishing in the Cell Press journal Newton on March 3, demonstrate that hot and burning droplets can bounce off cool surfaces, propelled by a thin layer of air that forms beneath them. This phenomenon could inspire new strategies for slowing the spread of fires and improving engine efficiency.
"We started with a very fundamental question: What will happen ...
UNIVERSITY PARK, Pa. — A synthetic microbiome therapy, tested in mice, protects against severe symptoms of a gut infection that is notoriously difficult-to-treat and potentially life threatening in humans, according to a team of researchers at Penn State. The team developed the treatment for Clostridioides difficile, or C. difficile, a bacterium that can cause severe diarrhea, abdominal pain and colon inflammation. C. difficile can overgrow when the balance of the gut microbiome — the trillions of organisms that keep your body healthy — is disrupted. The team said their findings could lead to ...
Many people who have tried to lose weight by cutting calories are familiar with this frustrating reality: at some point, the body stops shedding pounds. It senses the reduced calorie intake and responds by slowing down metabolism, causing it to burn fewer calories than before the diet.
This happens because the body perceives a potential starvation threat and adapts by conserving energy while still carrying out essential functions. It may seem incredibly unfair that the body doesn’t recognize the goal of weight loss and instead works against it by holding on to ...
About The Study: In this evaluation of a place-based, coordinated, countywide intervention, reports of both substantiated and unsubstantiated child sexual abuse were shown to be significantly reduced at the population level.
Corresponding Author: To contact the corresponding author, Jennie G. Noll, PhD, email jennie_noll@urmc.rochester.edu.
To access the embargoed study: Visit our For The Media website at this link https://media.jamanetwork.com/
(doi:10.1001/jamapediatrics.2024.6824)
Editor’s Note: Please see the article for additional information, ...
About The Study: This cross-sectional study found a recent increase in cervical cancer incidence in rural U.S. counties, specifically among white women. In addition, incidence was 25% higher and mortality was 42% higher in rural vs urban counties in recent years. The increase in incidence and mortality in rural U.S. counties may reflect lower screening coverage and lower utilization of diagnostic and therapeutic care, likely resulting from heightened access barriers experienced in rural areas. Additionally, if unaddressed, ...
About The Study: A proposed U.S. Drug Enforcement Administration rule could impede buprenorphine initiation for a substantial number of patients with opioid use disorder. In this study, more than 4,500 tele-buprenorphine initiations from 2020 to 2022—20% of tele-initiations overall—would have been prohibited under requirements for an in-person visit with the tele-initiating clinician prior to or within 30 days after tele-initiation.
Corresponding Author: To contact the corresponding ...
