Low concentration continuous femoral nerve block improves analgesia and functional outcomes after total knee arthroplasty in spinal anesthesia

ABSTRACT

BACKGROUND: Total knee arthroplasty (TKA) is associated with severe pain postoperatively. Femoral nerve block is commonly used for pain control after TKA. This study investigated whether continuous femoral nerve block (CFNB) can improve postoperative analgesia and functional outcome as compared to intravenous patient controlled analgesia (PCA) in patients with TKA. METHODS: We reviewed the electronic medical records of patients who underwent TKA with spinal anesthesia between March 2014 and February 2015. In Group IV, postoperative pain was managed by IV-PCA. Group CFNB received CFNB-PCA via a device. Thirty patients were enrolled per group. Patient outcomes were assessed by analgesia, functional outcomes, and health-related quality of life factors. RESULTS: Additional analgesics and additional nerve block for adequate pain control were significantly more frequent in the IV than CFNB group (P = 0.015 and P = 0.012, respectively). Range of motion up to 105 degrees was prolonged in the IV group than CFNB group (P = 0.013). EuroQol five dimensions score was improved in the CFNB group than IV group postoperative 3 weeks (P = 0.003). The incidence of transfusion due to postoperative bleeding was significantly frequent in the IV group than CFNB group (P = 0.042). CONCLUSIONS: Postoperative low concentration continuous femoral nerve block for analgesia after TKA improves analgesia, functional outcomes, and incidence of transfusion without falling risk.