The first step of two-stage hip revision: what affects the result?

Background. The most common method of treatment of chronic periprosthetic joint infection (PJI) is considered to be a two-stage revision arthroplasty. The efficacy of this technique is largely determined by the results of infection management after the first (debridement) stage, which may depend on many factors. At the same time, the widespread tendency to reduce the duration of patients’ hospital stay brings to the forefront the problem of long wait for the results of preoperative microbiological examination.

Aims of the study: 1) to retrospectively evaluate the efficacy of the debridement stage of chronic periprosthetic hip joint infection in 2021 depending on the availability of preoperative microbiological examination results; 2) to determine the factors influencing the treatment outcome.

Methods. Patients (n = 86) with chronic PJI of the hip were allocated into two groups depending on the presence or absence of results of the microbiological examination of preoperative biomaterials (aspirate and/or tissue biopsy) at the time of performing the first stage of the two-stage revision arthroplasty.

Results. The availability of final results of the microbiological examination (MBE) of joint aspirate at the time of surgery had no significant effect on the efficacy of infection management (p = 0.536; OR = 1.53, 95% CI 0.43-5.45). There was a significant reduction of the risk when the results of preoperative and intraoperative MBE coincided (p = 0.024; OR = 0.121, 95% CI 0.015-0.990). An increased risk of adverse outcome of the debridement stage of treatment was observed in the case of types 2C (p = 0.042; OR = 6.66; 95% CI 1.26-35.2) and 3B (p = 0.078; OR = 8.1, 95% CI 1.015-64.8) acetabular defects, type 3A femoral defects (p = 0.021; OR = 6.57, 95% CI 1.49-29.01), and connective tissue diseases (p = 0.062; OR = 5.25, 95% CI 1.05-26.2). The presence of microbial associations (p=0.02; OR = 6.75, 95% CI 1.36-33.44) and the presence of Gram-negative bacteria in them (p = 0.058; OR = 4.2, 95% CI 1.02-17.20) significantly worsened the treatment prognosis. As the number of patient’s risk factors increased, the probability of an unfavorable outcome increased significantly (p<0.001).

Conclusion. Polymicrobial infection, presence of Gram-negative bacteria in microbial associations, connective tissue diseases, types 2C and 3B acetabular defects, type 3A femoral bone defects, and total number of risk factors in one patient had a significant negative impact on the outcome of debridement surgery. Apparently, the results of the microbiological examination of preoperatively sampled biomaterials are much more important as a diagnostic criterion for suspected periprosthetic infection than as a criterion for the drug choice for etiotropic antibacterial therapy. However, this assumption should be studied on a larger sample of patients.