Synovial Fluid Findings and Demographic Analysis of Patients With Coexistent Intra-articular Monosodium Urate and Calcium Pyrophosphate Crystals.

Objectives: The aim of this study was to investigate the characteristics of arthritis in which monosodium urate (urate) and calcium pyrophosphate (CPP) crystals coexisted in synovial fluid (SF) to aid patient management and set a baseline from which to investigate the pathophysiological basis of an unusual coexistence of 2 disorders.

Methods: Synovial fluid analyses of 33,000 patients were reviewed, identifying those containing urate and/or CPP crystals. Synovial fluid cell count and differential cell count, together with patient age and gender, were retrieved from a computerized database spanning 22 years of SF analysis.