Gregorio Marañón Hospital Implants World’s First Personalized Metamaterial Bone Prosthesis

The Advanced Planning and 3D Manufacturing Unit (UPAM3D) at Gregorio Marañón University General Hospital in Madrid has designed, manufactured, and implanted the world’s first personalized metamaterial bone prosthesis. The 38-year-old patient, who had a high-grade bone sarcoma in the tibia, has shown no complications, retained mobility, and can walk without crutches. The prosthesis, made from a titanium alloy using 3D printing, was developed in collaboration with the Polytechnic University of Madrid and the Gregorio Marañón Health Research Institute.

The device uses aerospace-derived metamaterial structures composed of millimeter-scale rods that mimic the function of natural bone, absorbing mechanical load and preventing surrounding bone from weakening. It was filled with cancellous bone from the hospital’s own tissue bank, promoting integration and fixation. The prosthesis was tailored to the patient’s specific anatomy and load requirements, using a digital twin built from radiological images and simulations of real-world movements.

This development aligns with Spain’s growing emphasis on hospital-based 3D manufacturing. Hospitals like Hospital Universitario 12 de Octubre have achieved certification for custom medical devices, expanding their role beyond prototypes to direct patient care. Similar approaches have been used in China and India to treat complex bone defects with patient-specific implants, but the Gregorio Marañón prosthesis represents a step forward by replicating both the shape and mechanical behavior of natural bone.