This study showed that a single injection of a nerve-blocking agent can be used for pain control after a total knee replacement (TKR). The femoral nerve block (FNB) is given when the patient is anesthetized for the operation. The femoral nerve is blocked with a loss of sensation to the front and inner part of the knee. The effects last 12 to 16 hours.

There were two groups in this study. All patients were getting a TKR. The first group had anesthesia and a FNB. The second group had anesthesia and a fake nerve block (only saline was injected).

During the first 24 hours after the operation, patients with the FNB (Group A) asked for less painkillers than patients who didn't get the nerve block (Group B). Group A also used less morphine during their stay in the hospital.

No other differences were seen between the two groups. Both groups had the same results in rehab and stayed in the hospital about the same number of days. The authors conclude that pain after a TKR can be managed with a single-injection FNB. The added cost is very small, and the gains are large.

Reference:

Myron J. Szczukowski, Jr., MD, et al. Femoral Nerve Block for Total Knee Arthroplasty Patients: A Method to Control Postoperative Pain. In The Journal of Arthroplasty. September 2004. Vol. 19. No. 6. Pp. 720-725.'