Chinese Hospital Uses 3D Printed Tantalum Implant in Successful Knee Replacement Surgery

I remember years ago, when my grandfather had double knee replacement surgery, it took him a pretty long time to recover. But, thanks to 3D printing technology, the recovery time for this type of implant surgery has gone way down. According to CQNEWS.net, a website based out of the Chinese municipality of Chongqing, the percentage of osteoarthritis of the knee is increasing in the country’s adults, particularly in ages 50 to 59, and the First Hospital Affiliated to AMU in Chongqing performs roughly 400 knee replacement surgeries each year. Using 3D printed implants in knee replacement surgeries is certainly not a new concept, but manufacturing 3D printed knee joints out of tantalum, a metal commonly alloyed with titanium, shows a unique approach. We’ve seen 3D printed implants for knee replacement surgeries fabricated out of metals such as cobalt-chromium and nylon titanium, while porous tantalum is more often used to 3D print patient-specific implants for spinal implants and hip replacements.

Tantalum is a rare, blue-gray metal, with an extremely high melting point of over 3,000°C, and researchers have mixed it with titanium alloys before to improve the stress absorption of 3D printed implants. Because the melting point of tantalum metal is too high to produce using most 3D printers on the market, 3D printed metal implants are more likely to be made using a metal like titanium, but custom 3D printed tantalum implants do offer some unique positive characteristics. They are more compact, which can help make the implants more stable, thus reducing the risk of surgical complication and time in the operating room, as well as making the surgery itself more simple.

Recently, the First Hospital Affiliated to AMU completed what is believed to be the first knee replacement surgery using a 3D printed implant made out of tantalum.

Professor Yang Liu, head of the surgical department at the hospital, explained, “Total knee replacement is the most effective way to treat late-stage knee diseases, as it can reduce the pain for patients and improve their quality of life.”

When surgeons perform a conventional knee replacement surgery, they choose an off-the-shelf implant from a range of fixed sizes, and then spend a lot of precious time during the surgery making adjustments to it so the implant fits the patient. In addition, patients can also suffer from bone defects of varying shapes and sizes around the joint post-surgery, due to reasons such as post-operative infections. Unfortunately, most modular metals can’t be used to fix these defects – until now.

More and more Chinese surgeons are beginning to introduce 3D printing technology to their surgical procedures, which is of great benefit to their patients due to reduced surgical time and complications. Professor Liu, who works on an implantation research project with the National Key Research and Development Program of China, also collaborates with several domestic companies in order to 3D print porous tantalum joints, such as the one used for 84-year-old Zhang Jingui’s recent knee replacement surgery.

Professor Liu used CAD, 3D printing technology, and tantalum metal to make the implant itself, while tantalum pads were used to fill the patient’s large bone defects. The implant is said to be the world’s first 3D printed tantalum knee joint, and thanks to the technology, the surgery itself was far less risky for the elderly patient.

The very first day after his knee replacement surgery, Zhang had regained some knee mobility, and was able to perform a few basic movements in his hospital room. He should be able to go home in four to five days…proving once again that 3D printing technology can be used to make our lives better.

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[Sources: CGTN, MedNews.am]