1. Combined Measurement of Synovial Fluid α-Defensin and C-Reactive Protein Levels: Highly Accurate for Diagnosing Periprosthetic Joint Infection
by Carl Deirmengian, Keith Kardos, Patrick Kilmartin, Alexander Cameron, Kevin Schiller, and Javad Parvizi
J Bone Joint Surg Am
Volume 96(17):
September 3, 2014
©2014 by The Journal of Bone and Joint Surgery, Inc.

2. Synovial fluid α-defensin values (logarithmic scale) for the patients in the study.
Synovial fluid α-defensin values (logarithmic scale) for the patients in the study. Patients with metallosis are depicted separately from the aseptic cohort. The dotted red line indicates the α-defensin diagnostic threshold of 1.0 (signal-to-cutoff ratio [S/CO]). The five red points represent false-positive results, whereas the green point represents a false-negative result. PJI = periprosthetic joint infection.
Carl Deirmengian et al. J Bone Joint Surg Am 2014;96:
©2014 by The Journal of Bone and Joint Surgery, Inc.

3. Synovial fluid α-defensin levels in the total cohort of 149 patients, revealing a bimodal distribution with few values near the diagnostic cutoff.
Synovial fluid α-defensin levels in the total cohort of 149 patients, revealing a bimodal distribution with few values near the diagnostic cutoff. The red dotted line indicates the α-defensin diagnostic threshold of 1.0 (signal-to-cutoff ratio [S/CO]).
Carl Deirmengian et al. J Bone Joint Surg Am 2014;96:
©2014 by The Journal of Bone and Joint Surgery, Inc.

4. Synovial fluid CRP values (logarithmic scale) for the patients in the study.
Synovial fluid CRP values (logarithmic scale) for the patients in the study. Patients with metallosis are depicted separately from the aseptic cohort. The dotted red line indicates the CRP diagnostic threshold of 3.0 mg/L. The five red points represent false-positive α-defensin results, whereas the green point represents the false-negative α-defensin result. Note that the synovial fluid CRP measurement rectified all false-positive α-defensin results (red dots). PJI = periprosthetic joint infection.
Carl Deirmengian et al. J Bone Joint Surg Am 2014;96:
©2014 by The Journal of Bone and Joint Surgery, Inc.

5. α-defensin and CRP results are assessed in a combined algorithm.
α-defensin and CRP results are assessed in a combined algorithm. The CRP test is specifically utilized to improve the specificity of the combined algorithm.
Carl Deirmengian et al. J Bone Joint Surg Am 2014;96:
©2014 by The Journal of Bone and Joint Surgery, Inc.