Risk factors for recurrent infection in the surgical treatment of infected massive endoprostheses implanted for musculoskeletal tumours

Animal Models of Orthopedic Implant-Associated Infections and Revisions

Orthopedic implant-associated infections such as prosthetic joint infections (PJIs) lead to devastating complications for patients and impose significant financial burdens on the healthcare systems. Although the primary orthopedic implant associated infection rate is relatively low (0.3-9%), the reinfection rate after implant revisions can be as high as 20% to 40%. To evaluate novel therapeutic strategies for preventing and treating infections associated with primary and revision implants, it is essential to develop appropriate animal models that closely emulate clinical realities. Here we discuss existing animal models developed for orthopedic implant revision surgeries including small animal models in rats and mice, and larger animal models in rabbits, sheep, and mini-pigs. While larger animal models offer the advantage of more closely mimicking human surgical procedures, implant dimensions, and infection treatment protocols, rodent models are more cost-effective and better suited for screening experimental prophylaxes and therapeutics. Existing animal revision models have focused on primary infections established by Staphylococcal aureus (S. aureus) and revisions involving both one-stage and two-stage procedures. Further development of smaller animal implant revision models that implement more clinically relevant surgical procedures and recapitulate polymicrobial infections could facilitate the discovery and more rigorous evaluation of novel implant coating prophylaxes and therapeutics for reducing reinfection rates following implant revisions.

Controversies in orthopaedic oncology

Chondrosarcoma is the second most common surgically treated primary bone sarcoma. Despite a large number of scientific papers in the literature, there is still significant controversy about diagnostics, treatment of the primary tumour, subtypes, and complications. Therefore, consensus on its day-to-day treatment decisions is needed. In January 2024, the Birmingham Orthopaedic Oncology Meeting (BOOM) attempted to gain global consensus from 300 delegates from over 50 countries. The meeting focused on these critical areas and aimed to generate consensus statements based on evidence amalgamation and expert opinion from diverse geographical regions. In parallel, periprosthetic joint infection (PJI) in oncological reconstructions poses unique challenges due to factors such as adjuvant treatments, large exposures, and the complexity of surgery. The meeting debated two-stage revisions, antibiotic prophylaxis, managing acute PJI in patients undergoing chemotherapy, and defining the best strategies for wound management and allograft reconstruction. The objectives of the meeting extended beyond resolving immediate controversies. It sought to foster global collaboration among specialists attending the meeting, and to encourage future research projects to address unsolved dilemmas. By highlighting areas of disagreement and promoting collaborative research endeavours, this initiative aims to enhance treatment standards and potentially improve outcomes for patients globally. This paper sets out some of the controversies and questions that were debated in the meeting.