Epidemiology, Risk Factors, and Outcomes of Infections of Lower Limb MEGAprostheses

Megaprostheses are large orthopedic prostheses used to replace extensive portions of bone and joints, typically after the removal of bone tumors or in other conditions involving major bone loss (severe trauma, revisions). In the 1990s, they became the standard for reconstruction following resection of primary malignant bone tumors. Over time, the indications for the use of megaprostheses have expanded to include benign but locally aggressive bone tumors, bone metastases, and malignant soft tissue tumors. Currently, the number of megaprosthesis procedures for non-oncologic conditions is also increasing.

The anatomical sites where a megaprosthesis can be implanted include the femur (proximal, distal, or total), the proximal tibia, and the proximal humerus. Megaprostheses are modular metal structures (titanium, chrome-cobalt) that may include an artificial bone segment, a joint component (hip, knee, shoulder), and potentially an antibacterial coating (such as silver).

While a megaprosthesis represents an important therapeutic option for limb salvage, it also involves complex surgery with significant complication and failure rates. Periprosthetic infection, with incidence rates ranging from 3% to 30%, is certainly one of the most feared complications, as it is associated with increased morbidity and mortality, longer patient recovery times, and higher healthcare costs. Revising a megaprosthesis often presents additional technical challenges for orthopedic surgeons (for example, the impossibility of replacing the implant due to the lack of remaining tissues). Moreover, the rate of infectious complications in megaprostheses is higher than that of periprosthetic infections in standard joint replacements. Possible explanations include longer surgical times, greater soft tissue trauma, or patient-related factors (such as immunocompromised status in oncologic patients).

The use of megaprostheses to treat different types of lower-limb conditions is increasing, and these prostheses carry a higher risk of infection compared to standard implants.

There is a shortage of studies in the literature that specifically and thoroughly analyze risk factors for megaprosthesis infections, and existing studies often involve small patient cohorts.

It is therefore highly rational to identify specific infection risk factors for patients receiving a lower-limb megaprosthesis, if present, to highlight those that may be modifiable and ultimately reduce the infection risk for individual patients. The primary objective of the study is to identify risk factors for the development of infection in lower-limb joint megaprostheses within 2 years of implantation.

• Number of patients diagnosed with lower-limb megaprosthesis infection / number of patients who received a lower-limb megaprosthesis [Срок оценки: 24 months after prosthesis placement]
• Sex, Charlson index, indication for prosthesis placement, symptoms and etiology of the infection in patients diagnosed with megaprosthesis infection [Срок оценки: During prosthesis placement procedure and at the time of diagnosis of the megaprosthesis infection (assessed up to 2 months after prosthesis placement)]
• Age of patients diagnosed with megaprosthesis infection [Срок оценки: During prosthesis placement procedure and at the time of diagnosis of the megaprosthesis infection (assessed up to 2 months after prosthesis placement)]
• Number and type of surgical procedures performed for the treatment of megaprosthesis infection [Срок оценки: Within 24 months after prosthesis placement]
• Sex of patients diagnosed with megaprosthesis infection [Срок оценки: During prosthesis placement procedure and at the time of diagnosis of the megaprosthesis infection (assessed up to 2 months after prosthesis placement)]
• Number and type (molecule(s), route of administration, dosage, duration) of antibiotic treatments prescribed for the treatment of megaprosthesis infection [Срок оценки: Within 24 months after prosthesis placement]
• Percent of patients with megaprosthesis infection who experience clinical failure [Срок оценки: 24 months after prosthesis placement]
• Charlson index in patients diagnosed with megaprosthesis infection [Срок оценки: During prosthesis placement procedure and at the time of diagnosis of the megaprosthesis infection (assessed up to 2 months after prosthesis placement)]