TABLE I.

MSIS Criteria for PJI^*

One of the 3 following criteria must be met for the diagnosis of a PJI:

1. A sinus tract communicates with the prosthesis.

2. A pathogen is identified on culture of ≥2 separate samples of periprosthetic tissue or fluid.

3. 4 of the 6 criteria below are present:

Serum ESR and serum CRP concentration are elevated.

Synovial WBC count is elevated.

Synovial neutrophil percentage is elevated.

Purulence is found in the involved joint.

A microorganism is isolated in 1 periprosthetic tissue or fluid culture.

>5 neutrophils per HPF in 5 HPFs are detected on histological analysis of periprosthetic tissue at 400× magnification.

^*Modified from Parvizi et al.¹². MSIS = Musculoskeletal Infection Society, PJI = periprosthetic joint infection, ESR = erythrocyte sedimentation rate, CRP = C-reactive protein, and WBC = white blood cell, and HPF = high-power field.