Major complications associated with femoral nerve catheters for knee arthroplasty: a word of caution.

One thousand one hundred ninety patients underwent knee arthroplasty between January 2004 and July 1, 2007, and received an indwelling continuous infusion femoral catheter for postoperative ropivicaine pump infusion. Catheters were placed using electrical stimulation guidance. For the initial 469 patients (group 1), the continuous infusion ran for 2 to 3 days. In 721 patients, the infusion was discontinued 12 hours after surgery. There were 9 femoral nerve palsies (2 in group 1, 7 in group 2) and 8 major falls (0.7%). The overall complication rate was 1.5%, and the risk of permanent nerve injury was 0.2%. Patients should be made aware of these complications as part of the usual informed consent process before using this technique for postoperative pain control after knee arthroplasty. We did not observe fewer falls when the continuous infusion was stopped 12 hours after surgery.