Madrid doctors saved the leg of a patient with a tibial tumor by replacing the affected bone with a custom titanium implant

Madrid doctors saved the leg of a patient with a tibial tumor by replacing the affected bone with a custom titanium implant

On August 14, Gregorio Marañón Hospital in Madrid reported performing the operation on a 38-year-old patient with a sarcoma, a malignant tumor of the tibia. The doctors designed the titanium implant using images of the healthy leg, which allowed them to preserve the knee joint.

Infection and severe loss of bone density had left too little strong bone to secure a conventional implant while preserving the knee joint. Doctors and engineers used images of the patient’s healthy leg to create a digital model and calculate the loads placed on the tibia during walking, climbing stairs, and stumbling. The analysis showed how much load the remaining bone would need to bear and where the screws could be anchored.

Titanium rods form a lattice inside the implant. Its geometry was determined by the load calculations, and the surgeons filled its cavities with cancellous bone graft from a tissue bank. The metal lattice replaces the removed section of bone and holds the graft next to living tissue.

The implant weighs about 300 grams; in the computational model, it withstood a load of more than 500 kilograms. Nearly a year after the operation, the patient can walk, and the leg remains properly aligned with preserved knee mobility.

Oncologic surgeon Rubén Pérez, deputy director of the hospital’s research institute, explained how this operation differs from ordering a component from a manufacturer:

“Industry can produce custom solutions, but it is less common for a hospital to do so, particularly a public university hospital.”