A single injection of saphenous nerve block reduces postoperative bleeding after total knee arthroplasty

Abstract

In elderly patients, the vital parameters tend to fluctuate based on the blood volume status, which may cause sudden hypovolemic shock if the postoperative bleeding continues. Particularly, those who undergo surgery for arthritis needs to pay extra attention because the bleeding may persist over the joints after the surgery. Therefore, appropriate pain control is required to reduce the postoperative blood loss. This retrospective chart review study was conducted to assess the postoperative pain control and reduction of blood loss with a single injection of saphenous nerve block (SNB) in elderly patients with osteoarthritis. We reviewed the electronic medical records of patients who underwent knee total arthroplasty with spinal anesthesia between January and May 2016. A total of 51 patients participated in this study. All patients were treated with intravenous patient-controlled analgesia for the postoperative pain control, and additional analgesic agents were administered at a visual analogue scale above a score of 6. In 25 patients, SNB was performed using ultrasound with the administration of 0.75% ropivacaine (15 mL) after the surgery. Patients who received additional analgesics were significantly low in the nerve block group (P=0.009). Additionally, the volume of blood loss from catheter drainage was significantly low at 2 and 3 days postoperatively (P=0.013 and P=0.041, respectively) in the nerve block group. In patients who underwent total knee arthroplasty with osteoarthritis, only a single injection of saphenous nerve block was sufficient for the postoperative pain control and reduced bleeding. Key words: Nerve block, Pain management, Postoperative blood loss, Total knee arthroplasty