Optical measurements on human synovial fluid and its relevance to pathology

The feasibility of assessing knee joint pathology by measuring the optical properties of human synovial fluid was investigated. Absorption and fluorescence measurements were made in vitro. Many samples were found to contain traces of haemoglobin, which even in small concentrations is a strong absorber. This may have been present due to joint pathology or contamination from the extraction process. Synovial fluid was also found to be highly scattering at small wavelengths. This may obscure useful diagnostic information. The combination of these factors indicates that the method of optical diagnostics from synovial fluid is of little use at present.