Analgesic Effect of Femoral Nerve Block on Postoperative Pain and Ambulation after Total Knee Arthroplasty

Objectives: Determine the analgesic effect of a single injection femoral nerve block on postoperative pain and ambulation, after total knee arthroplasty. Methods: In a prospective study, 84 patients undergoing total knee arthroplasty were randomly assigned to receive: either one single injection femoral nerve block and 100mg paracetamol combined with lornoxicam 4 mg administrated twice intravenously for 5 days (group 1, n=42) or only the aforementioned analgesics without nerve block for the same period (group 2, n=42). Distance walked on 5 first postoperative days and VAS pain score during first 5 days were reported. Patients with bilateral osteoarthritis, previous leg injury or serious cardiovascular disease were excluded. Statistical analysis was performed by statistical packet STATA 8.0 and significance was set at p-value <0.05. Results: Patients of group 1 walked longer distance than patients of group 2 on postoperative day 1, 2 and 3 (p<0.05).The VAS pain score decreased significantly from 7.8/10 to 4.1./10 in Group 1 (P<0.05) and from average 8.1/10 to 5.9/10 in Group 2 (p<0.05) at 5 days after surgery. Patients of group 1 experienced less pain than patients of group2 at 5 days after surgery according to VAS pain score (p<0.05). Conclusion: Single shot of femoral nerve block provides efficient pain relief on early postoperative period after total knee arthroplasty. This is associated with better ambulatory performance.