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The Effect of Single-Injection Femoral Nerve Block On Rehabilitation And Length of Hospital Stay After Total Knee Replacement
  1. Hong Wang, M.D., Ph.D,
  2. Baher Boctor, M.D. and
  3. James Verner, M.D.
  1. From the Departments of Anesthesiology (H.W., B.B.) and Orthopedics (J.V.), Henry Ford Hospital, Detroit, Michigan.
  1. Reprint requests: Hong Wang, M.D., Ph.D., Department of Anesthesiology, Henry Ford Hospital, 2799 W. Grand Blvd, Detroit, MI 48202. E-mail:


Background and Objectives Continuous-infusion femoral nerve block (FNB) improves analgesia and rehabilitation after total knee replacement. In this study, we investigated the efficacy of single-injection FNB to achieve similar results.

Methods A total of 30 patients were prospectively and randomly assigned to receive 40-mL injections of either 0.25% bupivacaine (group B) or saline (group S) after total knee replacement. Blinded observers evaluated the patients for postoperative pain, morphine consumption, ambulating distances, and maximal knee flexion; pain was scored on the visual analog scale (VAS).

Results Compared with group S patients, group B patients had significantly lower VAS pain scores (P < .01 in the postoperative anesthesia care unit, P < .05 on the day after surgery); group B patients also showed significantly lower total morphine use (P < .05) and a lower incidence of morphine-related side effects. Significantly more group B than group S patients could ambulate on the day after surgery (93% v 46%, P < .05), and mean ambulatory distance was significantly better for group B than group S patients at discharge (166 ± 37 v 117 ± 24 feet, P < .01). Knee flexion was significantly better for group B than group S patients on the second day after surgery (70° v 60°, P < .01), but the between-group difference was no longer statistically significant at discharge. Mean length of acute hospitalization was significantly shorter for group B (3 days; range, 3 to 5 days) than group S patients (4 days; range, 3 to 6 days, P < .05).

Conclusions Single-injection FNB provided effective analgesia, facilitated early ambulation, and reduced the length of acute hospitalization in patients undergoing total knee replacement.

  • Femoral nerve block
  • Single injection
  • Postoperative pain
  • Rehabilitation
  • Hospital stay
  • Total knee replacement

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  • This study was performed at and supported by the Department of Anesthesiology, Henry Ford Hospital.

    Presented in part at the American Society of Anesthesiologists (ASA) Annual Meeting, San Francisco, CA, October 2000.