In vivo analysis of post-joint-preserving surgery fracture of 3D-printed Ti-6Al-4V implant to treat bone cancer

Cancer growth in the bone due to its random shape disables bone strength and thus changes its capacity to support body weight or muscles, which can crucially affect the quality of human life in terms of normal walking or daily activities. For successful patient recovery, it is necessary to remove the cancer-affected minimal bone area and quickly replace it with a biocompatible metal implant within less than 2 weeks. An electron beam-melted Ti-6Al-4V implant was designed and applied in a patient to preserve the natural knee joint close to the bone tumor. The developed implant fits the bone defect well, and the independent ambulatory function of the natural knee joint was restored in the patient within six weeks after surgery. A delayed fracture occurred six months after the successful replacement of cancer-affected bone with Ti-6Al-4V implant at the proximal meshed junction of the implant because of a minor downward slip. Microstructural, mechanical, and computational analyses were conducted for the fractured area to find the main reason for the delayed fracture. Our findings pertaining to the mechanical and material investigation can help realize the safe implantation of the three-dimensionally printed titanium implant to preserve the natural joints of patients with massive bone defects of the extremities.