Day zero ambulation under modified femoral nerve block after minimally invasive surgery for total knee arthroplasty: preliminary report

Ambulation in the early postoperative period of total knee arthroplasty is crucial, in order to avoid complications and obtain preferable outcomes. Although a femoral nerve block can provide enough postoperative analgesia after total knee arthroplasty, falling, or other accidents due to motor paresis, are potentially adverse events in patients who have received a conventional femoral nerve block. We devised a modified femoral nerve block to spare voluntary knee extension ability, and clinically applied it to patients who received total knee arthroplasty under minimally invasive surgery. In our new-approach nerve blockade technique, the main targets of the sensory nerves are the saphenous nerves which branch out from the femoral nerve trunk. All the patients rated pain at bed rest between 0 and 3 on a numerical rating scale 3 h after the operation. In addition, the rectus femoris muscle was not affected at all, and the surgically invaded vastus medialis oblique muscle was completely anesthetized. Patients were able to not only actively raise their extremities with their knee in extension, but also to flex the knee in the air without pain or aggravation. On day 0, the patients were able to walk around, with the leg that had been operated upon not giving way. Our anesthetic approach can provide better pain relief than a conventional femoral nerve block, while the patients achieve ambulation on the day of the procedure, following minimally invasive knee surgery.