Oxidant and anti-oxidant systems of synovial fluid from patients with knee post-traumatic arthritis.

It has been suggested that patients with knee post-traumatic arthritis (PA), associated or not to haemarthrosis (HA), display altered oxidant and anti-oxidant systems in their synovial fluid. This study aimed to establish whether this is really the case. Synovial fluid samples were obtained by transdermal arthrocentesis from 69 patients with PA (36 of them had HA) and 22 control subjects. The activities of synovial fluid zinc-copper superoxide dismutase (ZnCuSOD) and manganese superoxide dismutase (MnSOD) isoenzymes, catalase (CAT), glutathione peroxidase (GPX), glutathione reductase (GR) and glutathione-S-transferase (GST) enzymes, and malondialdehyde (MDA) concentration and synovial fluid viscosity were measured in the study groups. Patients with PA had significantly increased activities of all antioxidant enzymes, except CAT, and MDA concentration than did the controls. However, synovial fluid viscosity was found to be decreased in the study group, mainly in the HA subgroup. Results suggest that excessive free radicals production may exist in synovial fluid of PA patients and may contribute to knee joint destruction.