Analgesia After Total Knee Arthroplasty: Is Continuous Sciatic Blockade Needed in Addition to Continuous Femoral Blockade?

Abstract

Continuous femoral "3-in-1" nerve blocks are commonly used for analgesia after total knee arthroplasty (TKA). There are conflicting data as to whether additional sciatic blockade is needed. Our routine use of both continuous femoral (CFI) and sciatic (CSI) peripheral nerve blocks was changed because of concerns that sciatic blockade, and its motor consequences in particular, might obscure diagnosis of perioperative sciatic nerve injury. The revised protocol includes placing single-shot blocks and perineural catheters at both sites, but infusing local anesthetic postoperatively only in the CFI. CSI is reserved for patients having poorly controlled posterior knee or calf pain. A sample group of 12 patients treated with this protocol was followed. Ten of 12 patients required use of the CSI. Within 1 h of a 5-10 mL CSI bolus of 0.2% ropivacaine and beginning an infusion of the same drug at 5 mL/h, patients' median pain by verbal analog scale decreased from 7.5 to 2.0 (mean scores from 7.3 to 2.4). It was possible to maintain this level of analgesia until the third postoperative day when catheters were discontinued. Our experience suggests that, in most patients, adequate analgesia after TKA cannot be achieved with CFI alone and that the addition of CSI renders a significant improvement in analgesia.

Periarticular Injection in Knee Arthroplasty Improves Quadriceps Function

“…These results confirm that the sensitive sciatic nerve territory of the knee is not covered by a femoral nerve block alone. To encompass entire knee territories, lumbar plexus block [18], or femoral [9], sciatic [4], and obturator block could be combined [20]. However, a combination of these procedures adds complexity to patient care.…”

Is sciatic nerve block advantageous when combined with femoral nerve block for postoperative analgesia following total knee arthroplasty? a meta-analysis

“…Additionally, the combined innervation of the knee joint by both the femoral and sciatic nerves, and the overlap in their innervation of the anterolateral aspect of the knee, 46 further complicate accurate assessment. In fact, few studies 12 have conceived designs capable of reliably isolating pain transmitted by the femoral and sciatic nerves, which would permit accurate quantification of a block's analgesic effects on the individual nerves. 44 Furthermore, the human capacity to distinguish between pain arising from two adjacent sources as separate is subject to the interplay between spatial summation 47 and discrimination.…”

“…10 To improve pain control, it has been suggested that proximal sciatic nerve block (SNB) performed between the parascacral and mid-thigh regions should be added to FNB in patients undergoing TKA. [11][12][13] Unfortunately, the relevant evidence examining the role of SNB had been limited to observational studies and lowquality randomized controlled trials (RCTs), thus precluding a valid and reliable estimation of effect. 14 Recently, however, nine RCTs have been separately published, with seemingly mixed results.…”

The Chitranjan Ranawat Award: Periarticular Injections and Femoral & Sciatic Blocks Provide Similar Pain Relief After TKA: A Randomized Clinical Trial

“…Additionally, numerous studies have compared the efficacy of various types of neuraxial anesthetics and peripheral blocks [1,7,23,28,31,37,38]. The addition of a sciatic block to a femoral block provides better pain relief than femoral block alone, and various combinations have been studied [4,7,10,17,37]. However, we were unable to find any study directly comparing this commonly used combination of a continuous femoral block given with a single-shot sciatic block with that of a periarticular injection.…”