Volume 2 • Issue 3 • 1000124 J Med Diagn Meth ISSN: 2168-9784 JMDM, an open access journal Research Article Open Access Carrega et al., J Med Diagn Meth 2013, 2:3 DOI: 10.4172/2168-9784.1000124 Research Article Open Access Role of Nuclear Imaging and Intraoperative Frozen Section in Patients with Late Prosthetic Joint Infections Giuliana Carrega 1 *, Giorgio Burastero 1 , Lucia Di Ciolo 2 , Sergio Li Causi 3 and Giovanni Riccio 1 1 Infectious Diseases and Septic Orthopedic Unit (MIOS), Italy 2 Nuclear Medicine Unit, Italy 3 Pathology Service Santa Maria Misericordia, Albenga and Santa Corona Hospital, Pietra Ligure (Savona), Italy *Corresponding author: Giuliana Carrega, Infectious Diseases and Septic Orthopedic Unit, S.Maria Misericordia Hospital, Via Martiri della Foce,17031 Albenga,Italy, Tel: +39-182 546703, Fax: +39-182 546345, E-mail: carrega.castagnola@gmail.com Received June 05, 2013; Accepted July 20, 2013; Published July 24, 2013 Citation: Carrega G, Burastero G, Ciolo LD, Causi SL , Riccio G (2013) Role of Nuclear Imaging and Intraoperative Frozen Section in Patients with Late Prosthetic Joint Infections. J Med Diagn Meth 2: 124. doi:10.4172/2168-9784.1000124 Copyright: © 2013 Carrega G, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Abstract Background: Differential diagnosis of prosthetic joint infection and aseptic loosening can be not easy. The American Academy of orthopaedic Surgeons has recently published guidelines to perform a correct diagnosis using clinical fndings, infammatory markers, and microbiological cultures. In uncertain cases radionuclide imaging, frozen section and histopathology can be useful. Methods: Retrospective analysis of a cohort of patients with prosthetic joint infection examined with technetium- 99-labeled-leukocyte, frozen section and histopathology. Results: A cohort of 30 patients was evaluated in the period 2010-2012. Before surgery, technetium-99-labeled- leukocyte imaging was performed in 25 cases (in the remaining 5, infection was documented by the presence of a sinus tract). The nuclear scan was negative in 3 patients and positive in the other 22. Patients with negative scan were treated with one stage exchange. Patients with documented infection were treated with resection arthroplasty (2 cases) or two-stage exchange (25 cases). Frozen section examination, performed during removal arthroprosthesis, was negative in 4 cases (3 patients undergoing one stage exchange and one false negative) and positive in 26 cases. Histological fndings were in agreement with frozen section. A failure for persistence of infection (culture positive) was documented in 3/25 two stage exchange. Radionuclide scan was repeated before spacer removal in 20/25 two stage. It was negative in 16 (one false negative), positive in 4 cases (2 true positive in patients with persistence of infection, 2 false positive in patients with cultures negative). During prosthesis replacement frozen section and permanent histopathology was repeated with some discordant results for persistence of infammation in patients with documented resolution of infection. Conclusions: In our experience technetium-99-labeled-leukocyte imaging associated with intraoperative frozen section examination, have guided a correct management of patients with suspect prosthetic joint infections. In 2 stage exchange the sensibility seems better during frst step (prosthesis removal) than during prosthesis replacement. Keywords: Infection; Arthroplasty; Nuclear imaging; Histological diagnosis Abbreviations: PJI: Prosthetic Joint Infections; ESR: Erythrocyte Sedimentation Rate; CRP: C - Reactive Protein; AAOS: American Academy of Orthopaedic Surgeons; PET: Positron Emission Tomography (FDG-PET), WBC: White Blood Cells; PPV: Positive Predictive Value; NPV: Negative Predictive Value Introduction Prosthetic joint infections (PJI) represent a not frequent (1-2%) but severe complication of arthroplasty [1]. In relation to the time of onset afer surgery, PJI are classifed as “early”, in the frst 3 months, “delayed”, between 3 months and 2 years or “late”, more than 2 years afer surgery [2]. PJI remain a diagnostic challenge and a hard management for the clinician [3]. For these reasons the American Academy of Orthopaedic Surgeons (AAOS) has recently published guidelines to perform a correct diagnosis [4]. Te gold standard is represented by microbiological identifcation of the pathogen [5] with cultures of specimens obtained during arthrocentesis, tissue biopsy or surgery. Clinical symptoms and signs can only suggest a diagnosis. Fever is described in severe septic syndrome but when infection is restricted to periprosthetic tissue, pain can be the only symptom as in the aseptic loosening. Laboratory tests, such as erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) can be within the normal range or slightly elevated. Imagine techniques can be employed, but plain radiograph is not specifc and can mimic an aseptic loosing, computed tomography scan and magnetic resonance can have strong artefacts due to the metal component. Several nuclear medicine techniques have been proposed to defne more clearly diagnosis in dubious cases [6]. While bone scintigraphy can be falsely positive for years afer surgery because of bone remodeling, radio labeling of autologous peripheral white blood cells (WBC) scintigraphy is more sensitive and specifc. When revision is performed, frozen section and histopathologic analysis of periprosthetic tissue can diferentiate PJI or aseptic loosing. An area of connective tissue, called periprosthetic membrane, is interjected between prosthesis and bone and its composition is diferent in aseptic loosing and infection. A probable infection is suggested by acknowledgement in periprosthetic tissue of acute infammatory cells, defned as the presence of more than 5 neutrophil granulocytes (PMN) in at least 5 high power felds (400X). Permanent histology of periprosthetic membranes identify four diferent patterns: type I with presence of infltration predominantly J o u r n a l o f M e d i c a l D i a g n o s t i c M e t h o d s ISSN: 2168-9784 Journal of Medical Diagnostic Methods