TRANSCUTANEOUS OXYGEN-TENSION AND LASER-DOPPLER FLUXMETRY IN PATIENTSWITH RHEUMATOID-ARTHRITIS - A STUDY IN PREPATELLAR SKIN

Patients with rheumatoid arthritis undergoing primary total knee repla cement have an increased risk of developing post-operative wound compl ications. We examined the cutaneous microcirculation of 45 rheumatoid patients and 45 age and sex matched healthy controls using transcutane ous oxygen (TcPO2) and laser Doppler fluxmetry (LDF). LDF values were lower in rheumatoid patients only if they had a long duration of disea se (> 20 years) (p = 0.01), but values were similar to the controls in the remaining patients. TcPO2 was significantly raised in all rheumat oid patients (p < 0.001). Within the rheumatoid patients, the presence of nodules was associated with even higher TcPO2 levels (p = 0.02). T he use of corticosteroids, the ESR, and the haemoglobin level did not influence flux or transcutaneous oxygen. We believe that the high TcPO 2 levels seen in rheumatoid patients, in the presence of normal or red uced LDF, are explained by thinning of the skin. A reduced cutaneous m icro-circulation was found only in patients with a long duration of di sease (> 20 years). Both factors may contribute to the increase in pos t-operative wound complications seen in rheumatoid patients.