Ischial Tuberosity Osteomyelitis: A Rare Complication Following Platelet-Rich Plasma Injection

Case: A 48-year-old man developed severe left buttock pain and elevated C-reactive protein following a third platelet-rich plasma (PRP) injection for proximal hamstring tendinopathy. Magnetic resonance imaging (MRI) and positron emission tomography–computed tomography (PET-CT) demonstrated ischial bone marrow edema and cortical erosion with intense uptake. Two CT-guided aspirations were sterile. A closed endoscopic bone biopsy revealed Pseudomonas aeruginosa . Treatment with 5 weeks of intravenous ceftazidime followed by 6 weeks of oral antibiotics normalized inflammatory markers and resulted in near-complete radiologic resolution at 5 months, without the need for surgical debridement. Conclusion: This first reported case of PRP-associated ischial osteomyelitis highlights the role of minimally invasive pelvic bone biopsy and the importance of postinjection vigilance.