Reported success rates of the different surgical options to treat periprosthetic infection vary in the literature. However, these rates rely on how authors define success. The goal of this study was to determine the most commonly used definitions of success based on a classification system published by the Musculoskeletal Infection Society. We found most studies did not use the strictest definitions of success, and success rates decreased when stricter definitions were used. 

This is a meta-analysis of six studies describing the cutoff values of white blood cell count and polymorphonuclear percentage in synovial fluid for the diagnosis of acute postoperative peri-prosthetic joint infection (PJI). 
We found that both the WBC count and PMN percentage are good markers for diagnosis of acute postoperative PJI. However, the synovial WBC count is more powerful in diagnosing acute postoperative PJI.

Our study showed that ultrasound-guided aspiration of a total hip arthroplasty was more commonly successful and resulted in fewer dry aspirations than fluoroscopy. Ultrasound-guided aspiration yielded a larger volume of fluid than fluoroscopy, even when excluding dry aspirations. Ultrasound was more sensitive than fluoroscopy in diagnosing prosthetic joint infection (PJI) using culture results only and 2018 Musculoskeletal Infection Society (MSIS) International Consensus Meeting (ICM) criteria.

While there is no gold standard test to diagnose periprosthetic joint infection (PJI), we believe synovial fluid analysis, especially preoperatively, is a critical step in differentiating between infection and aseptic failure. Adding simple and inexpensive biomarkers such as synovial C-reactive protein (CRP) or adenosine deaminase (ADA) and combined interpretation can be helpful in the context of inconclusive results.

In a first evaluation, the accuracy of a novel multiplex PCR (polymerase chain reaction) panel for rapid detection of pathogens in patients with a clinical suspicion of acute septic arthritis of native and prosthetic joints is assessed. Clear benefit is seen in patients with a suspected native septic arthritis and late acute prosthetic joint infection. This indicates that the panel allows for fast tailoring of antibiotics and may prompt the surgeon for surgical lavage in doubtful clinical cases.