Metal artifact reduction sequence MRI in hip periprosthetic joint infection management

Aims: There is currently no validated noninvasive method to determine infection control prior to prosthesis reimplantation during the two-stage revision process for hip periprosthetic joint infections (PJI) after total hip arthroplasty (THA). This prospective study investigates whether metal artifact reduction sequence (MARS) MRI can serve as a diagnostic reference for infection control before second-stage revision surgery by analyzing artifact-reduced MRIs in patients with hip PJI prior to reimplantation. Methods: Patients with hip PJI after THA who entered the two-stage revision process between January 2019 and January 2024 were prospectively and consecutively enrolled. Based on the Musculoskeletal Infection Society (MSIS) criteria, 23 patients achieved infection control after the interval period (prior to reimplantation), and 11 experienced infection recurrence after spacer implantation (prior to repeat debridement). All patients underwent MARS MRI prior to both first-stage surgery and second-stage reimplantation. Data collected included patient demographics (sex, age), ESR, CRP, intraoperative pathology, culture results, and MARS MRIs. Two imaging specialists reviewed the MARS MRIs obtained prior to the first-stage surgery and prior to the second-stage reimplantation, evaluating regression of prior infectious lesions, emergence of new lesions, and overall infection control. Their assessments were then compared with intraoperative pathology and culture-confirmed infection status. Results: MARS MRI revealed significantly more frequent findings of bone oedema, soft-tissue oedema, and joint effusion in patients with recurrent infection compared to those with controlled infection after spacer implantation (p = 0.002). The imaging specialists' evaluations were in complete agreement with the clinical findings confirmed by pathology and cultures. Conclusion: Evaluating the difference in MARS MRIs between the first-stage and second-stage preoperative periods, and focusing on oedema signals in the bone and soft tissues surrounding the prosthesis, provides a useful noninvasive indicator for determining infection control prior to two-stage reimplantation.