Abstract
BACKGROUND Periprosthetic joint infection (PJI) is a potentially catastrophic complication after orthopedic surgery. Biofilm formation and infection with multidrug-resistant pathogens significantly increase the difficulty of achieving successful treatment. CASE REPORT A 36-year-old woman presented with a 6-month history of left hip pain. Three months prior to presentation, she had been definitively diagnosed with a pelvic giant cell tumor and undergone hemipelvic resection with custom prosthesis replacement. Chronic PJI developed postoperatively. Etiological examination revealed mixed infection with methicillin-resistant Staphylococcus epidermidis, extended-spectrum ß-lactamase-producing Klebsiella pneumoniae, and Pseudomonas aeruginosa. The patient underwent 8 debridement procedures with targeted antibacterial treatment. Antibacterial dosing was guided by the ratio of the area under the curve to the minimum inhibitory concentration of vancomycin plus rifampicin for biofilm penetration, together with ciprofloxacin against P. aeruginosa. The treatment strategy emphasized antibiotic rotation based on dynamic microbiome monitoring, surgical debridement with negative pressure drainage, and optimization of vancomycin trough concentration to 15-20 μg/mL via therapeutic drug monitoring. Infection did not recur during nearly 4 years of follow-up. The infection was ultimately controlled, and the prosthesis was preserved. CONCLUSIONS Patients with giant cell tumors of the pelvis who undergo prosthesis replacement should be closely monitored for PJI. Combination therapy with vancomycin and rifampicin can eradicate biofilm infections caused by coagulase-negative staphylococci, offering a potentially feasible non-revision treatment strategy for complex PJI in patients with financial constraints.