The popliteal nerve block is a regional anesthetic technique commonly used for surgical anesthesia and postoperative analgesia in foot and ankle procedures. By depositing local anesthetic around the sciatic nerve in the popliteal fossa, it provides sensory and motor blockade of most structures below the knee. Its principal advantages include prolonged analgesia, reduced opioid requirements, and improved postoperative comfort. Depending on the anesthetic technique and surgical requirements, it may be used independently or alongside general anesthesia [1,2].
The sciatic nerve originates from the L4–S3 spinal roots and consists of two major components: the tibial and common peroneal nerves. These travel together within a common connective tissue sheath before separating in the popliteal fossa. The level of bifurcation varies considerably between individuals. In a cadaveric study, Vloka et al. identified a mean division point 60.5 mm proximal to the popliteal crease, with distances ranging from 0 to 115 mm [3]. This anatomical variability has important implications for block success because injection near only one branch may produce incomplete anesthesia. The medial foot and ankle receive sensory innervation from the saphenous nerve, which is not covered by the popliteal block and may require separate blockade [2,3].
Several approaches to the popliteal sciatic nerve block have been described. The posterior approach provides direct access to the nerve, typically with the patient prone, whereas the lateral approach permits blockade in the supine position. A medial approach is also possible but is less commonly employed. Nerve stimulation can assist localization through characteristic foot movements, with plantarflexion generally considered more predictive of successful sensory blockade than dorsiflexion. Ultrasound guidance allows visualization of the nerve, its bifurcation, adjacent vessels, and local anesthetic distribution, improving procedural precision [2].
Injection technique significantly influences block characteristics. Local anesthetic may be administered proximal to the sciatic bifurcation or separately around the tibial and common peroneal nerves. An alternative involves injection within the common paraneural sheath at the bifurcation while remaining external to the individual nerve epineurium. In a randomized study, Perlas et al. demonstrated faster sensory and motor blockade with this technique than with separate distal injections. Mean sensory onset decreased from 21 to 14 minutes, while motor onset decreased from 23 to 15 minutes, accompanied by more extensive longitudinal anesthetic spread [4].
Clinical effectiveness depends on several factors, including patient characteristics and procedural technique. In a retrospective study of 143 popliteal blocks, Hegewald et al. reported a 76.2% success rate, with higher age and lower body mass index associated with greater success. Neither block approach nor duration of operator training significantly influenced outcomes [1]. Long-acting local anesthetics may provide approximately 14–20 hours of analgesia, while continuous perineural catheter techniques can extend postoperative pain relief [1,2].
Although generally well tolerated, potential complications include incomplete blockade, infection, neuropraxia, and unintended intraneural or intravascular injection. Appropriate needle positioning and observation of anesthetic spread are therefore important. Prolonged sensory blockade may also obscure postoperative pain or paresthesia associated with swelling beneath restrictive casts, emphasizing the importance of postoperative surveillance and patient education [2,4].
The popliteal nerve block is a valuable component of perioperative analgesia for foot and ankle surgery. Understanding anatomical variation, selecting an appropriate approach, and optimizing local anesthetic deposition are essential for achieving reliable blockade while minimizing complications.