Additional femoral catheter in combination with popliteal catheter for analgesia after major ankle surgery

Abstract

Background: The contribution of the saphenous nerve in pain after major ankle surgery is unknown. The aim of this study was to evaluate its contribution in this context.

Methods: Fifty patients were included in this prospective, randomized, controlled study. In all patients [Group P (popliteal) and Group F (popliteal+femoral)], a popliteal catheter was placed before operation and ropivacaine 0.5% (30 ml) administered via this catheter; major ankle surgery was then performed under spinal anaesthesia. In Group PF patients, an additional femoral catheter was sited before operation and ropivacaine 0.5% (10 ml) administered. Six hours after spinal anaesthesia (defined as T(0)), a continuous infusion of ropivacaine 0.3% (14 ml h(-1)) was started through the popliteal catheter until T(24). Then, the concentration was reduced to 0.2% until T(48). Patients in Group PF received continuous ropivacaine 0.2% (5 ml h(-1)) through the femoral catheter from T(0) to T(48). I.V. morphine patient-controlled analgesia was used as a rescue analgesia. Pain at rest, pain with movement, adverse effects, and i.v. morphine consumption were assessed. Pain at rest and on movement was evaluated 6 months after operation.

Results: Pain at rest was comparable in the two groups. In Group PF, patients had significantly reduced pain during movement in the postoperative period (P=0.01) and 6 months after operation (P=0.03). Morphine consumption was significantly reduced in Group PF at T(0)-T(24) and T(24)-T(48) (P=0.01). Adverse effects were comparable in both groups.

Conclusions: The addition of continuous femoral catheter infusion of ropivacaine to a continuous popliteal catheter infusion improved postoperative analgesia during movement after major ankle surgery. This effect was still present 6 months after surgery.