Management of Subacute Osteomyelitis of the Tibia with Concurrent Prosthetic Joint Infection Following Total Knee Arthroplasty: A Case Report

Abstract

Background: Osteomyelitis and periprosthetic joint infection (PJI) following total knee arthroplasty are significant musculoskeletal infections associated with substantial morbidity, prolonged treatment, and increased healthcare utilisation. Despite advances in surgical techniques and antimicrobial therapy, the management of subacute osteomyelitis and TKA-associated PJI remains challenging because of biofilm formation, diagnostic complexity, and the risk of recurrent infection. Aims: To report a rare case of early methicillin-resistant Staphylococcus aureus (MRSA) periprosthetic joint infection (PJI) after total knee arthroplasty (TKA) associated with contiguous subacute tibial osteomyelitis and to describe a prosthesis-preserving management strategy. Presentation of Case: A 37-year-old man with post-traumatic osteoarthritis secondary to a malunited tibial plateau fracture and multiple previous reconstructive procedures underwent primary left TKA using a fully constrained hinged prosthesis. Early postoperative cultures grew MRSA. One month later, he presented with pain, purulent discharge, and sinus formation over the proximal tibia. Inflammatory markers were elevated, whereas the leucocyte count remained normal. The findings were consistent with acute postoperative PJI with contiguous subacute tibial osteomyelitis. Treatment consisted of implant retention with extensive open debridement through the previous approach, tibial polyethylene insert exchange, and pulsatile irrigation. The tibial sinus tract was explored to bone, with sampling of seropurulent material and bone. Tibial guttering, limited osteotomy of devitalised bone, and packing with vancomycin-loaded bone cement were performed. Targeted antimicrobial therapy included intravenous vancomycin and oral rifampicin. The patient showed a good early clinical response, with controlled pain, dry wounds, and preserved distal neurovascular status. Discussion: Persistent drainage after TKA may reflect a dual infectious process involving both the prosthetic joint and adjacent bone. In selected early infections with stable implants and acceptable soft tissue conditions, debridement, antimicrobial therapy, implant retention, modular component exchange, and local antibiotic delivery may preserve both limb and prosthesis. Conclusion: Early MRSA PJI associated with subacute tibial osteomyelitis may be managed using a prosthesis-preserving approach when meticulous debridement, modular exchange, and combined systemic and local anti-staphylococcal therapy are applied.