Saphenous Nerve Block vs. Femoral Nerve Block for Total Knee Arthroplasty

Study Summary

Currently, the regional anesthetic standard of care for total knee replacement surgery is combined spinal/epidural to provide long-lasting pain relief with or without a femoral nerve block (FNB). The femoral nerve block refers to a technique that your anesthesiologist can use to numb the thigh muscle for approximately 18 hours after surgery. While this technique offers significant pain relief, it is possible it may cause muscle weakness and increase patients' recovery times. Hence there is a need for an alterative anesthetic technique, one that may help minimize postoperative pain as effectively as a femoral nerve block, while not causing weakness of the thigh muscle. The saphenous nerve, a branch of the femoral nerve, provides sensation to the knee. Thus it is hypothesized by "blocking" or anesthetizing the saphenous nerve with local anesthetic closer to where it branches off, the area around and below the knee will feel numb. Yet unlike the femoral nerve block, the thigh muscle itself will still be able to function. For patients undergoing two total knee replacements at one time or bilateral total knee replacement, they will be randomly assigned to receive a femoral nerve block on one leg and a saphenous block on the other. Pain levels will be measured and thigh muscle strength will be tested using a dynamometer before surgery, 6-8 hours following anesthesia administration, and on postoperative days 1 and 2.

Primary Outcome

The primary outcome is the postoperative pain in each leg within the first 24 hours postoperatively. VAS pain scores could range from 0 to 10. Higher values represent a worse outcome.

Conditions Studied

Interventions

• PROCEDURE Study Technique
• PROCEDURE Control Technique

Study Locations (1)