ABSTRACT
Introduction: Hip bipolar hemiarthroplasty is commonly done for elderly patients who suffer from femoral neck fractures, with good functional outcomes. Prosthetic acetabular protrusio is a rare complication following bipolar hemiarthroplasty and can occur in prosthetic joint infections (PJIs) due to destructive osteolysis and resorption of surrounding bone. Among PJI pathogens, Cutibacterium acnes is increasingly being implicated. In our paper, we review the current literature of C. acnes PJIs and report a unique case of C. acnes infection of hip bipolar hemiarthroplasty complicated by protrusio acetabuli. Case Report: The patient is a 77-year-old Asian-Chinese man who suffered from left hip pain 10 years after bipolar hemiarthroplasty surgery. Radiographic evaluation showed acetabular protrusio with extensive femoral osteolysis. Subsequent intraoperative cultures revealed C. acnes infection. The patient successfully underwent antibiotic treatment and a two-staged revision total hip arthroplasty. Conclusion: C. acnes is an increasingly recognized cause of PJIs and can cause significant morbidity. It should not be simply regarded as a contaminant of tissue or cultures. C. acnes PJIs require antibiotic treatment and early surgery with debridement and revision. This reported case presented technical challenges due to the infection resulting in prosthetic acetabular protrusio.
