Extended Femoral Nerve Sheath Block After Total Hip Arthroplasty

To the editor: I read with interest the report by Singelyn et al. (1) on the comparison of continuous versus patient-controlled femoral nerve sheath block after total hip arthroplasty. Although patient-controlled analgesia boluses (5 mL per 30 min) of 0.125% bupivacaine with clonidine 1 μg/mL and sufentanil 0.1 μg/mL were associated with the smallest local anesthetic consumption and the most patient satisfaction, I do not agree it is the regional technique of choice after total hip arthroplasty. We showed recently that the continuous epidural infusion (with a rate in mL/h calculated by [height in cm − 100] × 0.1) of ropivacaine 0.1% + 1 μg/mL sufentanil provided superior pain relief after total hip replacement with only minimal side effects over a postoperative period of 48 h (2). Because of the low concentration of local anesthetic used and the individually adapted infusion rate, we did not see any potential risk of toxicity caused by accumulation of ropivacaine after a prolonged period of infusion. Moreover, motor block is negligible during epidural infusion and patients can be mobilized soon. In addition, information on the degree of motor block with bupivacaine 0.125% + clonidine + sufentanil would have been interesting. Finally I would like to emphasize that patients in the present study received an additional 90 mg per day IV ketorolac, the maximum daily recommended dose of this potent nonsteroidal antiinflammatory drug (3). Is the patient-controlled analgesia femoral nerve sheath block indeed the technique of choice for postoperative analgesia after hip arthroplasty disregarding the favorable epidural combination of small-dose ropivacaine and sufentanil?