We thank Drs. Li and Wang for their thoughtful and detailed commentary on our recent publication, “Continuous Adductor Canal Block Compared to Epidural Anesthesia for Total Knee Arthroplasty”.1 The respondents offer valuable perspectives on the interpretation and potential extension of our findings.

We acknowledge the multifaceted nature of postoperative pain management following total knee arthroplasty (TKA). This single academic center large database retrospective study focused primarily on opioid consumption as a proxy for pain control. Incorporating standardized pain assessment tools, such as the Visual Analogue Scale (VAS) could allow for ease of generalizability to other studies. However, we would argue that in addition to opioid consumption, measurements of functional outcomes, such as length of hospital stay and time to ambulation, provide more practical, meaningful and comprehensive metrics for functional pain control compared to VAS pain scores. Furthermore, the well-documented issues with the VAS and other simple pain scores—including, for example, intrasubject variability,2 high minimal clinically important difference (MICD),3 non-linearity,4 diminished reliability in elderly patients,5 and issues with patient pain sensitivity6—suggest they may be insufficient to capture the multifaceted nature of acute pain.7 We agree with the respondents that psychological factors such as anxiety and depression, is indeed essential for a holistic understanding of pain perception and management. Previous research has shown the significant impact of psychological states on postoperative pain experiences and recovery, emphasizing the importance of addressing these factors in future investigations.8–10

Regarding the technical aspects of continuous adductor canal block (cACB), we appreciate the observation that details such as injection site, catheter placement accuracy, and depth were not elaborated upon. Our protocol adhered to standardized guidelines for cACB placement and blocks were placed by a dedicated regional anesthesia and acute pain team with minimal variations in practice. We agree that more detailed descriptions of these technical parameters may provide additional context and aid reproducibility. Studies have demonstrated that variability in catheter placement can significantly affect the efficacy of nerve blocks, reinforcing the need for precise reporting and technique optimization.11,12

The point about operative techniques and their potential impact on the range and duration of nerve blocks is well-taken. While our study aimed to minimize variability by standardizing surgical and anesthetic protocols across centers, subtle differences may indeed exist and could merit further exploration. Previous work has highlighted how surgeon-dependent factors influence outcomes following regional anesthesia, suggesting that these variables warrant further scrutiny.13,14

As you noted, our study primarily focused on short-term outcomes, including pain control, mobility, and opioid consumption, given the immediate postoperative period’s critical role in patient recovery and satisfaction. However, we concur long-term outcomes, such as functional recovery, chronic pain, and complication rates, are significant. Longitudinal studies have shown that analgesic modalities can have lasting effects on functional recovery and quality of life, supporting the need for extended follow-up in future research.15–19

Finally, respondents inquire about the lower incidence of venous thromboembolism (VTE) in the cACB group, which raises an important discussion. While earlier ambulation likely played a contributory role,20,21 the direct influence of analgesic techniques on hemodynamics and coagulation function warrants further exploration.22 This is an intriguing hypothesis that aligns with findings from prior studies demonstrating that regional anesthesia may positively influence thromboembolic outcomes through multiple mechanisms, including enhanced early mobility and altered coagulation dynamics.20–22

In summary, feedback from the responders highlights critical areas for further research that could build upon and refine the insights from our study. We hope our publication serves as a foundation for ongoing investigation into optimizing analgesic strategies for TKA patients.

Thank you once again for your engagement with our work and for contributing to this important discussion.

The authors report no conflicts of interest in this communication.

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