Sciatic block with Mepivacaine (3-4 mg/kg) revealed successful in 91.9% of 340 rheumatoid patients with Keller/Clayton operation. In unsufficient blocks (8.1%) supplementary anesthesia by femoral nerve block, reblocking the sciatic nerve or local anesthetics secondarily gave good operating conditions. In three cases it was necessary to use additional spinal anesthesia. The concomitant sympathetic block gives an immediate cessation of sweating and a long lasting evaluation of skin temperature.