Postoperative analgesia after total knee arthroplasty.

We read with great interest the article of Wang et al.1 concerning the use of continuous local anesthetic infusion via catheters placed with ultrasound guided and nerve stimulator beside femoral nerve for postoperative analgesia after total knee arthroplasty (TKA). We congratulate them on the presentation of the article. However, we would like to add some comments. We agree with author that rehabilitation after TKA is an important determinant of post-operative functional reconstruction of knee.1 Physical therapy with early joint mobilization is also an important aspect to achieve good results. Therefore pain management after TKA is essential and may effect success rate of surgery. Regional analgesia is commonly used for TKA as it has lesser side-effects and better analgesia when compared with traditional oral analgesics.2 Among the regional analgesia techniques, continuous epidural analgesia and continuous femoral block analgesia are preferred to use after TKA.3 Continuous epidural analgesia has definite effectiveness, and a few systemic side effects. It has been widely applied in clinical practice. However, this procedure still causes respiratory depression, hemodynamic instability, intestinal obstruction, urinary retention, pruritus, motor block, and walk limitation.4 Continuous femoral nerve block has special advantage for the analgesia in postoperative pain.5,6 It is that this technique may have less side effects than the others but continuous epidural analgesia may be more successful with postoperative pain management. Anatomically, the knee joint takes its nerve supply primarily from the femoral nerve; however, there seems to be an important component from the sciatic nerve that evinces as pain related to calf and leg.2 Previous studies are inconclusive concerning the necessity of sciatic nerve block and also there are nearly an equal number of studies discussing adequate and inadequate block with femoral nerve block alone.7 However a study of Zugliani et al. 8