152 - Negative Taps: Potential Role for Preoperative Ultrasound-Guided Synovial Biopsy

Purpose: In the preoperative workup for total joint arthroplasty or revision, the presence or absence of joint infection often determines surgical candidacy and approach, typically utilizing a single-stage operation in noninfected cases and a two-stage operation in infected cases. Unfortunately, conventional arthrocentesis is often negative or yields insufficient fluid, precluding accurate determination of infection status preoperatively. The purpose of this study is to assess the utility of preoperative ultrasound-guided synovial/periprosthetic tissue core biopsy (USGSB) as a new adjuvant diagnostic tool for ruling out joint infection in patients with dry/negative arthrocentesis.

Materials and Methods: A total of 31 patients underwent USGSB of the knee, hip, or shoulder by musculoskeletal radiologists. Biopsies were performed in patients with a history of native septic arthritis undergoing workup for primary arthroplasty (n=12), or patients with existing total arthroplasty being evaluated for prosthetic joint infection (n=19), who had a dry/negative tap. Three 18-guage biopsy cores were obtained using a Bard Marquee coaxial biopsy system and sent for culture, pathology, and sequencing. For those patients who subsequently underwent surgical intervention, biopsy results were compared to intraoperative cultures. Those who did not undergo surgery were followed to assess for any future clinical or laboratory evidence of infection in that joint.

Results: Subsequent surgical intervention was performed in 41.7% of native joints and 47.4% of prosthetic joints. US-guided synovial tissue biopsy demonstrated high specificity (92.9%) and negative predictive value (92.9%) for detection of joint infection. Of those with a negative USGSB, 40.0% of native joints and 55.6% of prosthetic joints were successfully managed non-operatively, with no further evidence of infection. No procedural complications were associated with the intervention.

Conclusion: Ultrasound-guided synovial tissue biopsy has a high specificity and negative predictive value for the diagnosis of native and prosthetic joint infection in patients without sufficient fluid for conventional arthrocentesis. USGSB may therefore serve as a powerful tool to help rule out infection in such patients, potentially simplifying clinical decision making. For those requiring surgical intervention, this additional diagnostic information facilitates surgical planning and has the potential to decrease the need for multi-stage operations.