:TIMELINE
🦴🛰️🖨️
2019-01-01 | Pierre Chazel, 38, is diagnosed with high-grade bone sarcoma of the tibia.   Surgeons remove the tumour, leaving a structural gap in the leg bone.
2021-01-01 | A post-surgical infection destroys the remaining bone density. No commercial   prosthesis can bond to what is left. Amputation of the leg is the only option on the table.
2024-01-01 | Gregorio Maranon Hospital in Madrid partners with engineers at the Polytechnic   University of Madrid. They build a digital twin of Pierre's healthy leg from radiological scans.
2024-01-01 | The team runs computer simulations of every load the tibia must bear: walking,   climbing stairs, stumbling. The internal structure of the prosthesis is optimised to match.
2025-01-01 | A personalised titanium lattice implant is 3D-printed. Millimetre-scale rods   are arranged so the metal mimics the mechanical stiffness of living bone tissue.
2025-01-01 | Surgery at Gregorio Maranon. Screws are placed in the strongest remaining bone,   planned to the millimetre. Donor spongy bone is packed inside to help the implant fuse.
2026-01-01 | One year post-op: Pierre walks. The hospital announces the world first. A second   patient has already received the same implant; a wrist and a sternum version are in preparation.
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:INFO
What Is a Metamaterial?
A metamaterial is not defined by what it is made of, but by how it is structured. By arranging titanium rods at the millimetre scale into a precise lattice, engineers can make the metal behave mechanically like something completely different, in this case, human bone.

The same principle is used in aerospace. Satellite panels and aircraft structural components use metamaterial lattices to be both light enough to fly and strong enough to survive extreme vibration and thermal stress. The Gregorio Maranon team borrowed that logic and applied it to reconstructive surgery. "We are reproducing bone from metal bars," lead UPM engineer Luis Saucedo told reporters after the announcement.
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:STATS
[icon:CHART] Prosthesis material | Titanium metamaterial lattice (3D-printed)
[icon:USERS] Hospital and research partner | Gregorio Maranon Hospital + UPM Madrid
[icon:TARGET] Body site of the world-first implant | Tibia (lower leg)
[icon:CLOCK] Time between surgery and the patient walking | Approximately 12 months
[icon:FIRE] Next planned implant sites | Wrist and sternum
[icon:STAR] Number of patients treated so far | 2 (a third and fourth in preparation)
[icon:CHART] Original sector for metamaterial technology | Aerospace (satellites, aircraft)
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:JOURNEY
From Aerospace to Operating Theatre
1 Roots
2 Insight
3 Precision
4 Manufacture
5 Proof
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:QUOTE [quotetype:plain, subtitle:Luis Saucedo · UPM engineer · Gregorio Maranon team]
We are reproducing bone from metal bars.
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:NOTE
What this means for other patients. Conventional prostheses fail when infection or cancer leaves too little healthy bone to anchor them. The metamaterial approach sidesteps that problem because the lattice can be tuned to any geometry and bonded with donor bone. The team expects to publish results enabling other hospitals to replicate the technique. Sternum and wrist versions are already in preparation at Gregorio Maranon, and the approach could in principle be extended to almost any load-bearin
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:LINK
https://www.euronews.com/health/2026/08/15/madrid-hospital-creates-first-bone-metamaterial-prosthesis-prevents-leg-amputation
Euronews: Madrid hospital creates first bone metamaterial prosthesis, August 2026