The Advanced Planning and 3D Manufacturing Unit of the Madrid hospital has designed and implanted a personalised titanium implant in the tibia of a 38-year-old patient. The piece, which mimics bone, now allows him to walk unaided.
The Gregorio Marañón University General Hospital has made history once again in the field of medicine. Its Advanced Planning and 3D Manufacturing Unit (UPAM3D) has designed, manufactured, and implanted the world's first personalised metamaterial bone prosthesis. The patient, a 38-year-old male, was treated for a high-grade bone sarcoma in the tibia and, almost a year after the surgery, can now walk unaided in many cases.
The prosthesis, made from a titanium alloy using 3D printing within the hospital itself, was created because there was no implant on the market capable of saving the patient's leg without compromising knee mobility. The piece does not replace the bone but imitates it: it is made up of millimetre-scale bars that recreate the shape and function of bone, and is capable of absorbing stress, preventing the surrounding bone from weakening due to lack of use.
The structure weighs only 300 grams and can withstand a weight of over 500 kilos, making it particularly robust for daily life. Additionally, it was filled with spongy bone from the hospital's Bone and Osteotendinous Tissue Bank, which promotes bone integration and fixation of the implant. Subsequent imaging tests confirmed the favourable adaptation of all elements.
The case originated from a complex clinical situation: after an infection and a severe reduction in bone density in the tibia, the bone could not support a conventional implant. Therefore, the medical team opted for a personalised design, adapted not only to the patient's anatomy but also to the function of the affected limb.
The design was based on the patient's radiological images, from which a digital twin of his healthy leg was constructed. Real loads that a tibia bears while walking, climbing stairs, or stumbling were simulated on it, and with that information, it was calculated, point by point, how the internal network of the piece should be structured to ensure that the weight was transmitted exactly where the bone could bear it. The fixation screws were oriented towards areas of better bone quality and the surgery was planned with millimetric precision.
The operation proceeded without difficulties and, almost a year later, the patient has not presented any infections or complications related to the intervention. He maintains alignment and mobility of the knee, and his recovery has been satisfactory.
This advancement is the result of the collaboration between the Gregorio Marañón Health Research Institute and the Polytechnic University of Madrid, utilising aerospace technology applied to medicine. The hospital is a national reference centre (CSUR) for sarcomas of the locomotor system, both in adult and paediatric populations.
For patients in the Community of Madrid, this milestone represents a beacon of hope in the treatment of complex bone tumours, as it brings the manufacturing of personalised implants closer to a public hospital environment. The next step will be to expand the experience to more selected cases, as long as the anatomy and function of the limb allow.
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