Radiological Evaluation of 3D Printed Porous Collars in Hip and Knee Resection Prostheses: Pilot Study.

Inclusion Criteria: * age \> 18 years at the time of surgery. * patients undergoing hip and knee resection prosthesis surgery with the use of collars porous 3D printed. * date of intervention: starting from the regular entry into use of 3D printed porous collars at the reference center. * Patients operated on for primary tumor outcomes. * Patients operated on for infection. * Patients operated for revisions with severe loss of bone substance. * Patients capable of giving informed consent and obtaining written informed consent (prospective part/patients in follow-up). Exclusion Criteria: * Patients lost to follow-up and/or for whom radiographic and clinical documentation is not available corresponding to the post-operative moment and the clinical follow-up visit (6 months and 1 years).