The value of hip aspiration versus tissue biopsy in diagnosing infection before exchange hip arthroplasty surgery.

The exclusion of infection is the most important factor in determining treatment options in a failed hip arthroplasty. Preoperative biopsy in the form of aspiration or tissue biopsy can be used to diagnose infection. Preoperative aspiration and tissue drill biopsy were performed in 273 consecutive patients under general anesthesia 3 months before exchange arthroplasty surgery. The results of the preoperative aspiration and tissue biopsy cultures were compared with the definitive intraoperative tissue cultures obtained at surgery. Seventy-one of 273 (26%) hips were infected. Overall accuracy of aspiration was 90.1% and tissue biopsy 87.9%. The sensitivity and specificity was 80% and 94% for aspiration and 83% and 90% for tissue biopsy. Positive predictive value and negative predictive values were 81.4% and 93.1% for aspiration and 73.8% and 93.8% for tissue biopsy. The more invasive tissue drill biopsy offers no advantage over aspiration in terms of bacterial accuracy and results in more false positives.