The goal of this observational study is to collect a large and homogeneous case report of periprosthetic infections in megaprostheses in patients with a history of bone sarcoma.

The incidence of periprosthetic infections (PJI) is high in megaprostheses (MP), 3-30% after primary surgery, up to 60% after prosthetic revision. Patients with megaprosthesis implanted in a primary sarcoma of bone have an increased risk of infection, compared with joint prostheses implanted on arthrosis, due to several factors, including treatment with chemotherapy, extensive periarticular soft tissue sacrifice, and duration of surgery. PJI of an MP can result in important consequences: prolonged hospitalizations, expensive treatments, multiple surgeries, risk of amputation and reduced quality of life.

Diagnosis and treatment of MP infections are challenging. Surgery is the focus of treatment, and identification of the microorganism responsible for infection is necessary for diagnostic confirmation and to set up targeted antibiotic treatment.

Treatment, similar to standard joint replacement, includes surgical cleaning without implant replacement and complete revision of the prosthesis in one or two stages. Data currently available in the Literature about patients with infection of a megaprosthesis implanted after excision of a bone sarcoma is scarce; in particular, most case series are small and heterogeneous.

The aim of this study is to obtain more information about this condition by collecting a large and homogeneous data of PJI in MP, in order to identify predictive factors in the treatment of PJI.

The treatments to which the patients underwent and thus analyzed for the study are those expected by normal clinical practice.

Inclusion Criteria:

• Patients with PJI caused by a megaprosthesis, implanted for a primary sarcoma of bone;
• Age >= 18 years at the time of diagnosis;
• Megaprosthesis site: proximal humerus, proximal femur, total femur, distal femur, tibia proximal;
• Prosthetic revision in two stages;
• Obtaining informed consent for the study

Exclusion Criteria:

• Early infection (within 6 weeks after implantation of the prosthesis);
• Recurrence of infection;
• Follow-up < 12 months after prosthetic re-implantation;
• Reconstruction other than a megaprosthesis (e.g., bone graft, composite prosthesis)

All participants meeting the inclusion criteria, processed from 2010 to 2020, were included.