Calcium crystals detected by scanning electronic microscopy in synovial fluid of patients with early knee osteoarthritis. relationships with infiammation and disease severity

Abstract

s / Osteoarthritis and Cartilage 22 (2014) S57–S489 S392 characterized by pain and/ or stiffness of knee and/ or hip. They were included at the first visit or within 6 months of the first visit to the general practitioner for these symptoms. Study centers comprise ten general and university hospitals located in urbanized and semiurbanized regions in the Netherlands. A special programwas developed to minimize loss to follow up, comprising newsletters, website and organizing symposia to present the results and progress of CHECK. An overview of measures that are included in the study can be found at our website www.check-research.com. Results: After 7 years a total of 105 (10%) participants had dropped out. Reasons included loss of interest (21%), comorbidity that complicated participating of CHECK too much (18%), death (12%), contact lost (11%), costs incurred for the study (5%), and other reasons (33%). Dropouts did not differ significantly from other participants in baseline characteristics. Over 7 years follow-up clinical characteristics including pain, stiffness and function of disease-specific (WOMAC) and the subscales of generic self-report questionnaire (SF36) on average did not change significantly, although at least half of the patients experienced radiographic progression. Scoring of 5-year follow up is complete: at this point, 50 % of the participants progressed by at least one Kellgren and Lawrence grade in the knee, and 25% in the hip. Preliminary analyses suggest the existence of several clinical and radiological phenotypes. Conclusions: CHECK is a valuable source of information of early symptomatic OA with a low loss to follow-up and a multidisciplinary approach that allows the collections of high-quality data on clinical, radiological and biochemical variables. 697 CALCIUM CRYSTALS DETECTED BY SCANNING ELECTRONIC MICROSCOPY IN SYNOVIAL FLUID OF PATIENTS WITH EARLY KNEE OSTEOARTHRITIS. RELATIONSHIPS WITH INFIAMMATION AND DISEASE SEVERITY R. Ramonda y, P. Frallonardo y, L. Peruzzo z, L. Tauro x, A. Scanu y, M. Lorenzin y, A. Ortolan y, P. Galozzi y, F. Oliviero y, L. Punzi y. yRheumatology Unit, Univ. of Padova, Padova, Italy; z Inst. for GeoSci.s and Earth Resources IGG-CNR, Padova, Italy; xDept. of GeoSci.s, Univ. of Padova, Padova, Italy Purpose: The presence of calcium crystals (CC) in synovial fluid (SF) of osteoarthritis (OA) is a well known and frequent feature. However, their role in the pathogenesis of OA is still unclear andmatter of discussion, in particular as regard the local inflammation. The objective of the study was to evaluate the presence of the most common CC, calcium pyrophosphate (dehydrate) (CPP) and basic calcium phosphate (BCP), in SF of the symptomatic knee OA (KOA, particularly in early disease stage (<1year) and to investigate their association with local infiammation, disease activityand severity. We performed an ultrasensitive analysis of SF crystals using the scanning electron microscopy (SEM) and the routinary method by compensated polarized ligth microscopy (CPLM) and alizarin red staining. Methods: Seventy-four (48 F, mean age 64.85 9.33 yrs, range 50-89 yrs) consecutive outpatients attending theRheumatology Unit, University of Padova with symptomatic KOA (according to the American College of Rheumatology criteria) underwent knee arthrocentesis. After optical and CPLM, the SF was analysed by SEM. Total white blood cell (WBC) count was performed and a cut-off of total WBC was established