[Clinical relevance of sialic acids determination in serum and synovial fluid in orthopaedic disorders].

Sialic acids, derivatives of neuraminic acid, are present as structural components of mucoprotein mainly in the alpha 1 and alpha 2-globulin regions, and they are known to change in diseases associated with acute inflammation or tissue necrosis. The present study was performed to clarify the significance of measurements of sialic acids in the serum and synovial fluid of patients with diseases in the field of orthopaedic surgery. 1. Serum sialic acids were markedly high in cases of acute pyogenic diseases and showed moderately high values in stage 2 or 3 of rheumatoid arthritis (RA). There was a close correlation with ESR in RA cases and with CRP in cases of acute pyogenic diseases. Differences in the correlation with ESR and CRP were seen in proportion to the severity of the inflammation. 2. Synovial fluid sialic acids were high in cases of RA, and within the normal range in cases of osteoarthritis. The values changed within this range in accordance with treatment. In RA cases, there was a significant correlation with monocytes in the synovial fluid. 3. Serum sialic acids appeared to be sufficiently useful as a parameter of inflammation independent of ESR and CRP, and synovial fluid sialic acids were also considered to be useful for differentiation between RA and OA.