Nov 7, 2015

This past month, doctors at the West China Hospital performed a miraculous surgery using the help of 3D printed prosthetics, marking another breakthrough for additive manufacturing in the medical world. More specifically, Dr Tu Chong Qi and his team from the orthopaedic department at the West China Hospital were able to successfully use a 3D printed metal prosthesis in a lower limb knee surgery, marking the first time 3D printing has been used for this type of load-bearing surgery. The operation is also the world’s first 3D printed trabecular metal tibial prosthesis reconstruction.

In the spring of 2011, a 15 year old from Mianyang City named Li was diagnosed with osteosarcoma bone cancer and underwent a surgery to salvage his afflicted leg. During this surgery part of his tibia was removed and was replaced with a traditional prosthesis. Unfortunately, however, the patient faced difficulties after the surgery as he suffered from chronic graft rejection.

Doctor Tu, who took on Li’s case, then had to find an alternative procedure to help Li and his diseased limb. He says, “If the next treatment uses traditional means, then the patient will be unable to keep his natural knee function as it may continue to generate rejection…” Finally, Dr Tu and his team at the West China Hospital found a solution in developing a 3D printed trabecular metal tibial knee prosthesis program in order to maintain Li’s knee function.

Tu Chong Qi and his team successfully performed the trabecular metal tibial prosthesis reconstruction just two weeks ago, and as a result the patient will be able to make use of his knee while the prosthesis helps to heal his body in the long term. Dr Tu says of the surgery, “Li’s surgery lasted 2.5 hours and was successfully completed… his knee flexion and extension are also very good…after being discharged the patient may participate in appropriate exercise.”

What makes the surgery quite unique is that the prosthetic made for the tibial trabecular area had to take into consideration that the tibia is a load bearing bone, essentially supporting most of the body’s weight. In other words, the prosthesis had to be designed to support a lot of weight and stress exerted by the body. “This is like building houses,” explains Tu, “We have solved the problem of load-bearing pillars.”

By 3D scanning the limb and compiling the data from the CT scan and creating a model of the afflicted bone, and going through a surgical simulation, the doctors were able to design a metal tibial trabecular prosthesis made to fit Li’s body and condition. Now the prosthesis can bear stress just as regular joints and bones do.

Because of 3D printing technology’s ability to create any shape and design, the doctors had the advantage of designing a microporous structure for the prosthetic implant, which allows for the patient’s own bone to grow into the prosthetic, unifying the structure to the body, and helping to biologically heal the leg. As Doctor Tu explains, “It is like how crops cannot be grown in stone.” 3D printing technology allows for the stone to be fertilized, so to speak, as though it is a layer of soil. Put another way, Dr Tu describes a traditional orthopaedic prosthetic reconstruction as based on a mechanical connection while 3D printing allows for the prosthetic reconstruction to be based on a biological connection.

Tu Chong Qi is excited about the successful surgery and sees the future of lower limb implants being changed and improved tremendously by 3D printing technology. The patient, Li, is also very happy with how the surgery went, expressing gratitude for Dr Tu and his team. “I’m feeling very good…and I can have a healthy life…I was very lucky,” says Li.



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