VOLUME 26, ISSUE 2
Arthroplasties is the question many anesthesiologists are pondering.
Jaeger’s prospective randomized study has been referred to as the “Landmark Study” of AC blocks comparing AC catheter versus placebo for total knee arthroplasty performed in Denmark. Spinal anesthesia was utilized in both groups and patients that requested general anesthesia were excluded. Subtler was the provider administered AC catheter bolus technique utilized in the study group. It is often not feasible for many practices and not cost effective for physicians to administer catheter boluses, although boluses can provide superior analgesia compared to continuous infusions via an epidural or TAP catheters. The study patient population and practice differed from this author’s practice because the patients’ in this study average BMI was 29.75 (highest being 35), whereas a BMI of 35 is far more common in Southeast Texas which creates an emphasis on reducing opioid consumptions because of the coexisting sleep apnea. In addition patients with chronic pain were excluded.
That being said, the first 24 hour opioid consumption in the ropivacaine group compared with the placebo group (40+/-21 vs. 56+/-26 mg, P=0.006). So overall, the “Straw Man Fell” and the AC block and catheter were superior to placebo and the patient’s consumed fewer opioids, but still averaged 40mg in 24hours and the patients apparently could walk very quickly after surgery. Not studied/published in this article were the average discharge day and what happened on postoperative day 2. The story doesn’t end here. Mudumbai et al published a prospective sequential series May of 2014 comparing adductor canal catheters versus continuous femoral blocks. They found ambulation distances were higher in adductor canal group on POD 1 and POD 2 with pain scores, daily opioid consumption and lengths of stay between the two groups being similar. Unfortunately, the study was not randomized, controlled or blinded. Both of these relatively small studies on adductor canal blocks and catheters are often touted as demonstrating superiority over the femoral blocks/catheters in that the AC causes little to no quadriceps weakness and requires similar consumption of opioids. Neither of these studies demonstrated both of those results.
The recent push for joint injections and adductor canal blocks may not be entirely unwarranted; 2010 and 2011 papers by Ilfield and Charous respectively address a causal link between falls and quadriceps weakness with continuous femoral nerve catheters. While there is no discounting both of those well-written studies, the obvious observation is that nerve blocks and catheters do cause motor weakness in addition to their primary indication anesthesia and analgesia. Both studies were not addressing nor were they designed to address the most important reasons for regional anesthesia. Those important reasons to perform regional anesthesia include the desire to avoid/minimize general anesthesia and opioid administration for patients that might die or suffer complications from severe coexisting disease. These are tantamount considerations in the setting of an aging American and Texan population where more than 1/3 are obese and often have obstructive sleep apnea.
Subsequently, respiratory depression secondary to opioid consumption is a severe reality. We must keep our eyes focused on the most important outcomes with patient survival of the perioperative period and hospital stay ranking the highest.
This author encourages the reader to critically evaluate publications on local infiltration/ intraarticular injections with extended release local anesthetics. This author believes the AC block and catheter will play a role and Anesthesiologists would be wise to learn the technique. However, it would be prudent to await more definitive studies before implementing in your total knee clinical pathways.
Our profession provides for our families and our careers are noble, but why would physicians truly care about Anesthesia except for a deep sense of compassion, empathy, and caring for others? When others don’t care about pain and suffering, don’t or won’t see postoperative complications associated with general anesthesia and suboptimal opioid management for our patients. May we logically and fervently advocate for evidence-based modern Regional Anesthesia and nonopioid adjuncts to improve those outcomes.
