To the Editor:
We read with interest the recent network meta-analysis by Terkawi et al.,1 which focuses on pain management modalities for patients undergoing total knee arthroplasty. The authors conclude that the combination of femoral and sciatic nerve blocks provides the best analgesia.1 Although some may suggest that this study1 warrants a change in clinical practice,2 we believe that these results should be interpreted with caution. It is not surprising that anesthetizing multiple nerves is superior to blocking a single nerve. However, the authors’ preferred intervention is associated with the highest incidence of peroneal nerve palsy (7.6%) and patient falls (2.28%).1 Readers should be aware that the authors excluded studies that combined multiple analgesic modalities.1 However, combining peripheral nerve block with periarticular injections offers advantages.3 Additionally, the authors’ rehabilitative outcomes were limited to range of motion and degree of flexion1 at 72 h. These may have been measured and documented differently at various institutions (e.g., passively, actively with/without assistance, while on a continuous passive motion machine). In addition, range of motion and degree of flexion at 72 h may not correlate with long-term outcomes. Ambulation distance and active measurements were not reliably analyzed by network meta-analysis yet play critical roles for meeting discharge criteria.
So how should readers interpret this study? We believe that one size does not fit all. Previous studies have already revealed the heterogeneity of anesthetic practice for total knee arthroplasty patients. Memtsoudis et al.4 have shown that most total knee arthroplasty patients in the United States (76.2%) receive general anesthesia alone, whereas only 12.1% receive any type of peripheral nerve block. Given these data, recommending a complex combination of both femoral and sciatic nerve blocks is totally impractical and does not improve access. Rather, introducing a single peripheral nerve block intervention in the context of multimodal analgesia may be more achievable.
Centers with an established multimodal analgesic total joint pathway have recently seen an essential shift in the application of peripheral nerve block for postoperative analgesia in the total knee arthroplasty patient with the implementation of the adductor canal block. Routine use of femoral3 and sciatic nerve blocks for pain control conflict with the goals of early active mobility and may delay diagnosis of perioperative common peroneal nerve injury, which can occur in 0.3 to 4% of patients.5 If patients are already receiving multimodal analgesia, peripheral nerve block, and periarticular injections,6 sciatic block may not offer added benefit.7
Total knee arthroplasty clinical pathways that combine multimodal analgesics with continuous peripheral nerve block have already been shown to reduce hospital length of stay3 and improve early participation in physical therapy.8 It seems evident that the pathway, and perhaps not the individual items themselves, is most important. We believe the more critical question that still needs to be answered is how to best tailor a multimodal total knee arthroplasty clinical pathway to a specific institution and patient population to provide the best pain control, promote early ambulation, improve patient satisfaction, and facilitate timely discharge.
Unrestricted educational program funding paid to Dr. Mariano’s institution from Halyard Health (Alpharetta, Georgia). Dr. Horn is a consultant for Teleflex (Wayne, Pennsylvania) and Halyard Health. The other authors declare no competing interests.