Rejoint teams up with GE: the only one company offering certified 3D printed knee prostheses made from cobalt-chrome.
Knee implants are fairly common, and the market is estimated to be around six million implants per year globally. Until very recently, knee arthroplasty relied entirely on the use of standard prosthetic devices, which were limited in terms of available sizes and could cause problems or discomfort to the patient down the line. This means that finding the optimal fit for a knee implant is crucial, especially as knee joints must withstand point loads of over 300 kilograms. An improper implant can result in pain and inflammation and does not have the same feel as natural bone for the patient.
REJOINT has recognized the potential of 3D printing to address this big need and is seeking to transform the knee arthroplasty market with a customized solution driven by additive manufacturing and artificial intelligence.
REJOINT is a pioneer in developing 3D printed knee prostheses made from cobalt-chrome. All the process starts from a patient-specific CT scan, which is then analyzed from an AI algorithm to obtain the best fit choosing among several thousand prosthetic configurations and identify patient specific alignment. To convert the prothesis design in a real implant, REJOINT uses GE’s Arcam EBM technology.
EBM 3D printing stands for electron beam melting. EBM is an utmost advanced manufacturing technology that, starting from a high energy source of electrons, melts the microparticles of a specific material. It works in a vacuum chamber without atmospheric gases thus granting to avoid any contamination and to manufacture parts more resistant to the pressures. The process also improves material density by minimizing inner porosity and it allows for reduced temperature gradient which helps avoiding the formation of tensile stress.
The EBM 3D printing can work with different materials, Rejoint has chosen a cobalt alloy because of its high corrosion resistance, wear resistance, high stiffness and good mechanical strength properties. For these reasons, this alloy is used to produce metal implants which have excellent fatigue life and less generation of wear debris.
“When it came to additive manufacturing, we were initially undecided about the most suitable solution for personalized cobalt-chrome prosthetics and were evaluating DMLM and EBM,” explained Gian Guido Riva, CEO of REJOINT. “Both modalities, in fact offer a good level of resolution and quality, but we ultimately opted for the GE Additive Arcam EBM Q10plus system. The knowledge and industrialization support that GE was able to provide us and the professional experience of their local team here in Italy also informed our decision.”
REJOINT is now working on the expansion of its portfolio by developing a fully uncemented solution for TKA with the integration of trabecular metal tibial plates printed from Titanium alloy powder and the introduction of personalized uni and bi-uni prosthetic systems. The development of these latter systems is being conducted in the frame of a broad and breakthrough project which aims at increasing their adoption and improving surgical results thanks to the introduction of an innovative tele-operated robotic platform.