The efficacy of continuous bupivacaine infiltration following anterior cruciate ligament reconstruction

Purpose: The purpose of this study was to determine whether continuous infiltration of a local anesthetic into the surgical wound for 48 hours will diminish the need for narcotics and improve the postoperative pain experience for patients undergoing anterior cruciate ligament (ACL) reconstruction using a patellar tendon autograft. Type of Study: Prospective, randomized, double-blind study with a placebo and an experimental group. Methods: Twenty-six patients were randomly assigned to receive either normal saline (placebo) or bupivacaine (experimental) for 48 hours. Both groups received a single intra-articular bolus injection of 35 mL of 0.25% bupivacaine and 5 mg. of morphine at the conclusion of surgery. The placebo group received an infusion of 2 mL/h of normal saline and the experimental group received an infusion of 2 mL/h of 0.25% bupivacaine, both for 48 hours. The anesthetic was infused using a disposable elastomeric pump (Baxter Healthcare, Deerfield, IL). Patients were evaluated using a pain and pain relief assessment questionnaire and visual analogue scale (VAS). Narcotic consumption was also documented. The pump was discontinued either by the patient at home or by a physical therapist. Results: There was a statistically significant (P < .05) difference in VAS pain and pain relief scores reported by patients receiving the infusion of 0.25% bupivacaine. Patients in the treatment group also consumed 37% less narcotics than the placebo group. The operating room time, tourniquet time, weight, and age of this population were similar in the 2 groups. There were no complications with the catheter technique. Conclusion: This report of a new technique suggests that surgical knee patients receiving local anesthetic infusion postoperatively experience less pain and require less narcotics. The disposable pump allowed administration of the medication on an outpatient basis.