Multistage Additive Manufacturing for Complex Limb Bone Deformity Reconstruction

Complex deformities of the limb bones may involve abnormal angulation, limb or bone shortening, abnormal rotation and structural bone loss. These deformities can result from previous trauma, bone nonunion, infection, tumour resection, congenital or developmental conditions, previous surgery or failed reconstruction. Treatment is challenging because correction of the deformity and reconstruction of the remaining bone defect often require several coordinated surgical stages. This multicentre prospective observational cohort study will evaluate the clinical outcomes of a multistage treatment pathway that incorporates three-dimensional imaging, computer-assisted surgical planning, additive manufacturing and patient-specific porous Ti6Al4V implants. Treatment decisions and the selection of surgical procedures will be made by the treating multidisciplinary team according to each patient's clinical condition and will not be assigned by the study. The study will include 30 adults with complex deformity of a major upper- or lower-limb bone. Participants will be followed for 12 months after definitive reconstruction. The study will evaluate maintenance of deformity correction and implant stability, restoration of bone length, angular and rotational correction, radiographic bone-implant integration, limb function, pain, progression to functional loading, reoperations and adverse events.