Innovation has allowed for opportunities of sustainability when asking the question, “what do I do with this used surgical knee replacement?”

Katie Hobbins, Managing Editor

June 6, 2023

2 Min Read
Artificial Knee
nopparit / iStock / Getty Images Plus via Getty Images

Medical advancements such as surgical hip, knee, and shoulder joint replacements, along with surgical interventions that use metal nails, screws, and plates have created a significant deposit of valuable metals and alloys within humans. However, when these implants and materials are removed for either replacement or postmortem, there are limited options available for reclaiming or reusing what’s gathered.

"Currently, a reclaimed implant would be processed in an induction furnace that uses a massive amount of energy with a commensurately large carbon footprint,” Peter Pecht, CEO of SMR said. And by ‘large carbon footprint’, he’s not kidding. Research published in Chemical Review by the American Chemical Society reported that the production of metals as a whole stand for 40% of all industrial greenhouse gas emissions, and 10% of the global energy consumption.

6K Additive, however, reported that with the use of its UniMelt reclaiming process, there is a 74% minimum energy reduction and 78% carbon emission reduction compared to traditional processes. The Uniform Melt State Process, or UniMelt, is 6K’s proprietary process technology based on high-frequency microwave plasma. A combination of high heat and highly reactive ions precisely spheroidizes metal powders while “controlling the chemistry and porosity of the final product,” according to 6K.

6K has entered into an agreement with Surgical Metal Recycling (SMR) to utilize used and out-of-spec implants, swarf, and used metal additive manufacturing powder supplied by SWR and will reprocess the material through the UniMelt platform — initially in the United States, and later in Europe. The premium powder that results from the process can be used in the creation of new parts through additive manufacturing, with the ultimate goal being to create new certified implants from existing parts through a sustainable and circular supply chain. A circular supply chain involves a company reusing or reprocessing materials to covert them into new product.

"There is a growing population that require medical titanium implants for knees, spine, and hips, this agreement creates a path to recycle these parts and enable new implant production with sustainably sourced feedstock,” said Frank Roberts, president of 6K Additive.

Starting with titanium (Ti64) and then eventually expanding to incorporate cobalt chrome, the UniMelt will use a controlled process in which oxygen is removed from the titanium powder. This means that the material grade can be improved. The process, according to the company, allows for greater than 90% yield of the desired particle size distribution compared to other plasma or gas atomization processes which typically have only 25-35%. 6K said that will further decrease cost and environmental impact.

“By recycling, reusing, and rejuvenating the metals we already have in the country, we can massively reduce the environmental impacts of metal extraction and processing for virgin material thanks to 6K's UniMelt platform,” Pecht said.

About the Author(s)

Katie Hobbins

Managing Editor, MD+DI

Katie Hobbins is managing editor for MD+DI and joined the team in July 2022. She boasts multiple previous editorial roles in print and multimedia medical journalism, including dermatology, medical aesthetics, and pediatric medicine. She graduated from Cleveland State University in 2018 with a bachelor's degree in journalism and promotional communications. She enjoys yoga, hand embroidery, and anything DIY. You can reach her at [email protected].

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