Study of synovial fluid for crystals by polarized microscopy for degenerative and metabolic joint diseases

Abstract

Background: Synovial fluid cytology is indicated in many joint diseases. There light microscopy fails to detect the pathognomic crystals deposited within synovial fluid which is closely related to the pathogenesis of osteoarthritis (OS) and other crystal related arthropathies. The polarized microscopy, therefore, is indicated for the examination of such fluids. Objectives: The comparison was drawn between light microscopy synovial fluid examination and polarized microscopy in the detection of pathognomic crystals. Materials and Methods: Thirty synovial fluids with varied clinicoradiological diagnosis aspirated from mostly large joints underwent conventional cytology by light microscopy and polarized microscopy. The rate of detection of crystals was evaluated. Results: The thirty patients in an age range of 21–80 years were recruited for the study. The crystals of calcium oxalate, monosodium urate, Charcot–Leyden crystals, cholesterol, homocysteine, and calcium pyrophosphate were assessed for deposition. It showed that light microscopy examination detected in six samples, whereas polarized microscopy detected in 14 samples. The rate of detection of crystals by polarized microscopy is more than twice that of light microscopy. The PPV and NPV for polarized microscopy are 100. Conclusion: Polarized microscopy of synovial fluid is advised to be carried out in the detection of crystal deposition in arthropathies for the earliest and appropriate management of the patient.