Effect of Synovectomy on the Uptake of Radioactive Technetium (Tc-99m) In the Knee Joint of Patients with Rheumatoid Arthritis

Scanning and profile counting were used to study the effect of synovectomy on the uptake of Tc-99m in the knee joints of patients with rheumatoid arthritis. The material consisted of 33 knee joints. The uptake of Tc-99m after synovectomy decreased with the abatement of the clinical inflammatory symptoms of the joint. The uptake was either normal or only slightly increased in patients whose joints were clinically asymptomatic. This was taken to be a sign of normalisation of the circulation in the regenerated synovium and the periarticular tissue of the joint. When the inflammatory symptoms persisted after synovectomy, the uptake of isotope in the joint remained high. The uptake correlated well with the clinical inflammatory symptoms (r=0.62, P < 0.001). Tc-99m profile counting can be used for objective evaluation of the therapeutic results. A drawback of the method, however, is its non-specificity; osteoarthritis, among other affections, causes an increase in the uptake of the isotope in the joint.