Stiffness after total knee arthroplasty (TKA) remains an issue despite numerous advances in the field. Could the pain management protocol be a factor?
A multi-center research team from the Boston University School of Medicine, the Madigan Medical Center in Tacoma, Washington, and the New England Baptist Hospital (Boston) pulled together data from 1,091 patients who had received either a single-shot femoral nerve block or a continuous femoral nerve block.
Their retrospective review, “Continuous Femoral Nerve Block Reduces the Need for Manipulation Following Total Knee Arthroplasty,” was published in the July-September 2022 edition of JBJS Open Access.
“We initiated this study to evaluate the efficacy of continuous and one-time peripheral nerve blocks in alleviating postoperative pain and potentially improving early range of motion after total knee replacement,” said co-author David Freccero, M.D., assistant professor of Orthopaedic Surgery at the Boston University School of Medicine, to OTW.
The team reviewed data from two surgeons over three years; the surgical techniques, postoperative oral analgesic regimens, and rehabilitation protocols were identical for all patients. Patients with <90° of flexion at six weeks postoperatively underwent closed manipulation under anesthesia.
A total of 608 patients (55.7%) received continuous femoral nerve block and 483 patients (44.3%) had the single-shot femoral nerve block. The researchers found that 94 patients (8.6%) required postoperative manipulation for stiffness, including 36 (5.9%) in the continuous femoral nerve block group and 58 (12%) in the single-shot femoral nerve block group.
“The 50% reduction in the need for manipulation in the continuous femoral nerve block group was independent of primary surgeon,” wrote the authors. “No significant differences were observed between the groups in terms of postoperative range of motion, either at the time of discharge or at 6 weeks postoperatively. A history of knee surgery, decreased preoperative range of motion, and decreased range of motion at the time of discharge were significantly associated with the need for further manipulation under anesthesia.”
“Interestingly,” said Dr. Freccero to OTW, “our most important finding was that there was a reduction in the need for manipulation under anesthesia postoperatively in the continuous peripheral nerve block group compared to the single shot group. The longer duration of patient analgesia with the continuous nerve block likely resulted in improved patient tolerance of early physical therapy and improved knee range of motion.”
“This important finding highlights the role of optimal patient analgesia after total knee replacement in achieving early knee range of motion. This study demonstrates that further advancement in optimal pain management strategies, particularly in the early postoperative period are essential to improving patient outcomes after total knee replacement surgery.”
