Sub Sartorial Canal Block and Popliteal Block Versus Femoral Block and Popliteal Block in Ankle Surgeries

Ankle surgeries are severely painful. A sciatic nerve block is typically not enough to cover the pain sources (Delbos et al., 2019). It can be speculated that approaching the saphenous nerve in the subsartorial compartment distal to the point where it pierces the vastoadductor membrane but proximal to the point where it penetrates the crural fascia and becomes subcutaneous would selectively target the saphenous nerve without any decrease of quadriceps strength (Jensen et al., 2024). Previous study showed that femoral nerve block (FNB) provides good surgical anesthesia and good postoperative pain control for patients with ankle conditions (Lee et al., 2014). However, FNB leads to femoral quadriceps muscle weakness (Jaeger et al., 2013). Consequently, quadriceps weakness results in functional impairment and it is associated with an increased risk of postoperative falls (Johnson et al., 2013). Thus far, attempts to reduce quadriceps involvement after FNB without compromising analgesia have not been successful (Li et al., 2019). Partially because of the increase in the use of ultrasound guidance, a more targeted approach that only blocks sensory fibers of the femoral nerve that supply the operative site has been attempted; thus, the feasibility of sub sartorial canal block has been studied (Kopp et al., 2017). In recent years, sub sartorial canal block has been successfully used for postoperative pain control after knee surgery (Lavand'homme et al., 2022). However, no randomized, control study has compared sub sartorial canal block to femoral nerve block for ankle surgeries. We hypothesized that compared to femoral nerve block, sub sartorial canal block would demonstrate noninferior pain scores during surgery and until 48 hours postoperatively and cause less weakness in the quadriceps.