New Study Tackles Saphenous Nerve Blocks in Knee Surgery

During a total knee arthroplasty (TKA) is it effective and safe for a surgeon to use a saphenous nerve block? Yes, says new research from Duke University and Hospital for Special Surgery.

“Saphenous Nerve Block From Within the Knee Is Feasible for TKA: MRI and Cadaveric Study,” appears in the January 2018 edition of Clinical Orthopaedics and Related Research.

Co-author on the study, Joseph J. Kavolus, M.D. with the Department of Orthopaedic Surgery at Duke University Medical Center in North Carolina told OTW, “In the era of cost containment any opportunity to improve the economic efficiency of patient care without hindering outcomes is valuable.”

“Recent literature has focused on the importance of peripheral nerve block as an essential aspect of multimodal analgesia for total knee replacement.”

“Comparisons of surgeon-performed local infiltrative analgesia and anesthesiologist-performed peripheral nerve block have been equivocal with modest if any clinical difference, however not surprisingly there is some evidence that the combined techniques provide the best pain control. This paper seeks to evaluate if the surgeon can safely and effectively do both procedures.”

The authors wrote, “A retrospective analysis of 94 thigh-knee MRI studies was performed to determine the relationship between the width of the distal femur at the epicondylar axis and the proximal location of the saphenous nerve after its exit from the adductor canal and separation from the superficial femoral artery. These studies, obtained from one hospital’s MRI library, had to depict the saphenous nerve in the distal thigh and the femoral epicondyles and excluded patients younger than 18 years of age or with metal implants…”

Dr. Kavolus told OTW, “While other studies have tested procedural hypothesis on cadavers this investigation first used data obtained from colleagues in the radiology department to provide a roadmap for the best way to approach the cadaveric simulation of our technique, which we believe provides a stronger foundation for the viability of the technique.”

“Using our technique, a surgeon can reliably deliver an injection of a possible local anesthetic to the saphenous nerve proximal to the knee at the time of a total knee replacement.”

“Going forward a randomized trial of this technique compared to an anesthesiologist ultrasound guided adductor canal blocks is needed to determine the clinical significance of the study.”

“We propose a technique for surgeons to safely administer peripheral nerve blocks at the time of total knee replacement, however clinical investigations are necessary to determine the true safety and efficacy of the technique.”