Correlation of Aspiration Results With Periprosthetic Sepsis in Revision Total Hip Arthroplasty

A retrospective chart review was performed of all patients who had undergone revision total hip arthroplasty with a synovial aspiration with greater than 100 WBC since the institution of our electronic medical record. Infection was defined using a combination of criteria. A diagnosis of periprosthetic sepsis was established in 52 of the 253 included hips. No significant differences existed with respect to gender, age, BMI, Deyo–Charlson Comorbidity Index, or the cause of initial hip degeneration. Using receiver-operating characteristic curves accuracy was maximized for WBC of 745 or segmented cell count of 73.5% with a sensitivity of 98%, specificity of 37%, negative predictive value of 99% and accuracy of 50%. Application of the current American Academy of Orthopaedic Surgery Clinical Practice Guidelines (AAOS CPG) thresholds revealed a similar accuracy of 49%.