Osteomyelitis in peri-implant bone of hip prosthetic joint infection: prevalence and clinical impact

<b>Introduction</b>: Periprosthetic joint infection (PJI) after hip revision surgery shows variable failure rates, with the impact of osteomyelitis in the surrounding bone on outcomes remaining unclear. This study aims to examine bone osteomyelitis prevalence and its impact on hip PJI revision outcomes. <b>Material and methods</b>: This retrospective study reviewed 75 cases of chronic hip PJI patients undergoing hip revisions performed at a single center between January 2019 and June 2023. Only cases with peri-implant bone samples submitted for histology evaluation were included. Bone samples were assessed for osteomyelitis using histological criteria. Risk factors, including demographic data, preoperative infections, and previous revisions, were analyzed. Statistical significance was determined using Chi-square and Kaplan-Meier survival analysis ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>p</mml:mi> <mml:mo>≤</mml:mo> <mml:mn>0.05</mml:mn></mml:mrow> </mml:math> ). <b>Results</b>: A total of 52 cases of chronic hip PJI were included for final analysis. Up to 30.8 % of the cases ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>n</mml:mi> <mml:mo>=</mml:mo> <mml:mn>16</mml:mn></mml:mrow> </mml:math> ) presented histological signs of osteomyelitis. The success rate among those 36 cases where no signs of osteomyelitis were observed was 88.9 %, whereas, in the 16 cases where it was present, the rate dropped to 37.5 %. Histological signs of osteomyelitis were significantly associated with a prior history of multiple surgeries and unsuccessful antibiotic treatments ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>p</mml:mi> <mml:mo>=</mml:mo> <mml:mn>0.01</mml:mn></mml:mrow> </mml:math> ), the presence of a sinus tract ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>p</mml:mi> <mml:mo>=</mml:mo> <mml:mn>0.01</mml:mn></mml:mrow> </mml:math> ), and the need for additional debridement with spacer exchange after the first stage of a two-stage revision ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>p</mml:mi> <mml:mo>=</mml:mo> <mml:mn>0.001</mml:mn></mml:mrow> </mml:math> ). <b>Conclusion</b>: Patients with signs of osteomyelitis demonstrated a higher failure rate. Histological evaluation of periprosthetic bone should ideally be performed during the first stage of revision surgery to guide second-stage management and to improve outcomes.