The Effect of the Combination of Adductor Canal Block and Anterior Femoral Cutaneous Nerve Block on Postoperative Inflammatory Biomarkers in Total Knee Arthroplasty

Total knee arthroplasty (TKA) is a common and effective surgical intervention for advanced-stage knee osteoarthritis. However, postoperative pain remains a significant issue affecting the recovery process, opioid requirements, and patient satisfaction. Tissue injury resulting from surgical trauma triggers an inflammatory response that leads to pain. During this process, released mediators activate nerve endings, and the severity of inflammation is generally correlated with pain intensity.

Multimodal analgesia strategies are widely used for postoperative pain management. Peripheral nerve blocks reduce pain scores and opioid consumption, thereby facilitating early mobilization. The adductor canal block is a commonly used technique after knee surgery, providing analgesia to the anteromedial region of the knee while preserving quadriceps muscle strength. However, this block may not adequately anesthetize the anterior femoral cutaneous nerve (AFCN), which innervates the anterior aspect of the thigh. Therefore, an anterior femoral cutaneous nerve block is routinely added to the adductor canal block to improve control of anterior knee pain.

Recent studies have demonstrated that regional anesthesia techniques reduce the inflammatory response, as reflected by biomarkers such as the neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR). This reduction in inflammatory markers has been shown to attenuate the surgical stress response and accelerate wound healing. However, the number of studies evaluating the effects of peripheral nerve blocks on biomarkers such as NLR, PLR, aggregate index of systemic inflammation (AISI), and C-reactive protein/albumin ratio (CAR) in knee surgery remains limited.

In our clinic, the choice of anesthesia technique in daily practice is determined based on the surgical site, type of procedure, patient positioning, and the experience of the anesthesia team. In patients undergoing total knee arthroplasty, ultrasound-guided adductor canal block combined with an anterior femoral cutaneous nerve block is routinely performed for postoperative pain management. The efficacy and safety of both blocks have been demonstrated in regional anesthesia guidelines and previous studies.

The primary outcome of this observational study is to evaluate the effect of adding an anterior femoral cutaneous nerve block to the adductor canal block on the inflammatory response, as assessed by biomarkers such as NLR, PLR, AISI, and CAR, in patients undergoing total knee arthroplasty. Secondary outcomes include postoperative opioid consumption, incidence of nausea and vomiting, early mobilization, and wound healing.