Periprosthetic joint infections: a clinical practice algorithm.
OBJECTIVE
periprosthetic joint infection (PJI) accounts for 25% of failed total knee arthroplasties (TKAs) and 15% of failed total hip arthroplasties (THAs). The purpose of the present study was to design a multidisciplinary diagnostic algorithm to detect a PJI as cause of a painful TKA or THA.


METHODS
from April 2010 to October 2012, 111 patients with suspected PJI were evaluated. The study group comprised 75 females and 36 males with an average age of 71 years (range, 48 to 94 years). Eighty-four patients had a painful THA, while 27 reported a painful TKA. The stepwise diagnostic algorithm, applied in all the patients, included: measurement of serum C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) levels; imaging studies, including standard radiological examination, standard technetium-99m-methylene diphosphonate (MDP) bone scan (if positive, confirmation by LeukoScan was obtained); and joint aspiration with analysis of synovial fluid.


RESULTS
following application of the stepwise diagnostic algorithm, 24 out of our 111 screened patients were classified as having a suspected PJI (21.7%). CRP and ESR levels were negative in 84 and positive in 17 cases; 93.7% of the patients had a positive technetium-labeled bone scan, and 23% a positive LeukoScan. Preoperative synovial fluid analysis was positive in 13.5%; analysis of synovial fluid obtained by preoperative aspiration showed a leucocyte count of > 3000 cells μ/l in 52% of the patients.


CONCLUSIONS
the present study showed that the diagnosis of PJI requires the application of a multimodal diagnostic protocol in order to avoid complications related to surgical revision of a misdiagnosed "silent" PJI.


METHODS
Level IV, therapeutic case series.
Articular Replacements Excellence Center (CESAT) - Fondazione Onlus "...In Cammino...", Fucecchio, Italy.
Luigi
L
Volpe
New Mexico Veterans Affairs Health Care System (NMVAHCS) and Adult Reconstruction University of New Mexico, Department of Orthopaedics and Rehabilitation, Albuquerque, New Mexico, USA.
Pier Francesco
PF
Indelli
Articular Replacements Excellence Center (CESAT) - Fondazione Onlus "...In Cammino...", Fucecchio, Italy ; Orthopedic Clinic, University of Florence School of Medicine, Italy.
Leonardo
L
Latella
Articular Replacements Excellence Center (CESAT) - Fondazione Onlus "...In Cammino...", Fucecchio, Italy.
Paolo
P
Poli
The Breyer Center for Overseas Studies, Stanford University in Florence, Italy.
Jale
J
Yakupoglu
Articular Replacements Excellence Center (CESAT) - Fondazione Onlus "...In Cammino...", Fucecchio, Italy ; Orthopedic Clinic, University of Florence School of Medicine, Italy.
Massimiliano
M
Marcucci
THA; TKA; algorithm; arthroplasty; diagnosis; infection; joint