The Sciatic Nerve and Knee Arthroplasty

Abstract

T ricompartment (total) knee arthroplasty (TKA) consistently results in severe postoperative pain. Although providing a femoral nerve block dramatically improves analgesia, 80% to 90% of patients still experience pain requiring treatment with intravenous opioids in the immediate postoperative period.2,3 This pain is usually attributed to the sciatic and obturator nerves that contribute innervation to the knee joint, albeit less extensively than the femoral nerve. Although a lumbar epidural infusion will affect all 3 nerves, multiple investigations suggest that a continuous femoral nerve block offers similar analgesia with a more favorable adverse effect profile and is thus often cited as the ‘‘gold standard’’ following TKA. However, little consensus has emerged regarding the routine addition of a single-injection or continuous sciatic nerve block. This question is of great interest to health care providers considering the frequency that TKA is performed: more than 500,000 cases annually in the United States alone, with this number growing to 3.5 million in fewer than 20 years.