Long-term clinical outcome of two-stage revision surgery for infected hip arthroplasty using cement spacer

Periprosthetic joint infection (PJI) is a terrible complication after hip arthroplasty. Clinical feature of culture-negative PJI (CN-PJI) has not been well studied till now. In our study, we retrospectively analyzed long-term clinical results after two-stage revision arthroplasty using an antibiotic-impregnated cement spacer for CN-PJI. The purpose of this study is to investigate the clinical features and prognosis of CN-PJI after hip arthroplasty and to compare these with those of culture-positive PJI (CP-PJI).We retrospectively reviewed 15 CN-PJI cases and 70 CP-PJI cases following hip arthroplasty. The average follow-up period was 7.4 years (5-11.7 years). The demographics, laboratory findings, the time interval between antibiotic-impregnated cement spacer insertion and revision arthroplasty, and recurrence of infection were analyzed.The CN-PJI group showed a significantly higher incidence of prior antibiotic use ( p = 0.004) and lower serum C-reactive protein (CRP) level ( p = 0.001) than the CP-PJI group. Normalized time interval of CRP level in CN-PJI was shorter than that of CP-PJI group. The mean interval time for two-stage exchange arthroplasty was also significantly lower ( p = 0.049) in the CN-PJI group than the CP-PJI group. There was no case of treatment failure or major complication in CN-PJI group.The CN-PJI group after total hip arthroplasty could be treated successfully by two-stage exchange arthroplasty without any complications. Clinical course and prognosis of CN-PJI group was also better compared with that of CP-PJI group. Therefore, culture negativity of PJI cannot be always a poor prognostic factor for the treatment.