Single-shot plus continuous FNB versus single-shot FNB alone in total knee arthroplasty

Study Type: Therapy
OE Level of Evidence: 1
Journal Level of Evidence: N/A
OE EXCLUSIVE
Dr. M. C. Wyatt discusses single-shot plus continuous FNB versus single-shot FNB alone in total knee arthroplasty
Synopsis
One hundred patients scheduled for total knee arthroplasty under spinal anaesthesia and preoperative single-shot femoral nerve block were randomized to receive either continuous femoral nerve block with 0.125% bupivacaine for 48 hours after arrival to the postanaesthesia care unit, or to placebo saline. The purpose of this study was to evaluate the analgesic effect of continuous femoral nerve block as compared with placebo saline after total knee arthroplasty. Upon follow-up for Please login to view the rest of this report. Please login to view the rest of this report.
Funding: Non-Industry funded
Sponsor: Healthcare Otago Trust, The Wishbone Trust, University of Otago Medical School Bequest Fund, and The Richard Stewart Scholarship.
Conflicts: None disclosed
CONTENT IS LOCKED
Why was this study needed now?
Considerable pain can be experienced following total knee arthroplasty. As such, it is important that effective strategies are undertaken in order to limit and alleviate pain in these patients. Recently, there has been a push to limit the use of opioid analgesic agents (morphine patient controlled analgesia; PCA) in TKA, due to the risk of postoperative nausea and vomiting (PONV). This has led to the more prevalent use of nerve blocks for postoperative analgesia, although surgeons remain concerned with the possible risks of femoral nerve block use, in terms of postoperative motor weakness and falls. Single-shot femoral nerve blocks have traditionally been utilized, but there is interest in whether efficacy of continuous infusion may differ from single-shot nerve blocks.
What was the principal research question?
In patients undergoing TKA, is there a significant difference between groups treated with single-shot femoral nerve block plus continuous femoral nerve infusion and those treated with single-shot femoral nerve block alone, when considering pain, opioid consumption, and motor weakness within the first 72 hours postoperatively?
Population: One hundred patients scheduled for primary unilateral total knee arthroplasty under spinal anaesthesia. All cases were performed through a medial parapatellar approach without patellar resurfacing, with a cemented, posterior-stabilized, mobile-bearing knee prosthesis implanted. All patients were prescribed paracetamol (1g) 4 times daily, oxynorm (5-10mg) every 3 hours, and oxycontin SR (10mg) twice daily. Fentanyl PCA was begun on the evening after surgery if patient had taken more than 20mg of oxynorm or oral analgesia was deemed not sufficient to manage pain.
Intervention: Continuous femoral infusion: A femoral catheter was placed under ultrasound guidance, and single-shot nerve block was performed with 15mL 0.25% bupivacaine. Once in the post-anaesthesia care unit (PACU), a continuous infusion of 0.125% bupivacaine was begun at 10mL/hr for 48hr. (n=50 randomized; 43 analyzed) (Mean age: 68.2 +/- 7.0).
Comparison: Saline infusion (placebo): A femoral catheter was placed under ultrasound guidance, and single-shot nerve block was performed with 15mL 0.25% bupivacaine. Once in the (PACU), a continuous infusion of saline was begun at 10mL/hr for 48hr. (n=50 randomized; 43 analyzed) (Mean age: 68.8 +/- 8.2).
Outcomes: Primary outcome was maximum pain at rest within the first 72 postoperative hours, assessed using a visual analog scale (VAS). Secondary outcomes included knee range of motion, cumulative morphine consumption and need for PCA, side affects, and length of stay.
Methods: RCT: Patient-, assessor-, and surgeon-blinded, Prospective, Placebo-controlled.
Time: Pain was assessed at 4, 8, 12, 16, 20, 24, 30, 36, 42, 48, 54, 60, 66, and 72 hours after surgery. Knee ROM was measured on postoperative days 1, 2 and 3. All other outcomes were documented over the perioperative period.
What were the important findings?
What should I remember most?
How will this affect the care of my patients?
The authors responsible for this critical appraisal and ACE Report indicate no potential conflicts of interest relating to the content in the original publication.
January 27, 2016
Should reduce falls due to quads weakness, too.