Difference in Occurrence of Rebound Pain in Patients Undergoing Surgery Under Popliteal Block or Ankle Block

This is a monocentric, comparative prospective randomized controlled trial. Patients will be randomised into 2 groups and will receive either a sciatic popliteal nerve block or an ankle block (single dose locoregional block injection before the surgery) for elective forefoot surgery in addition to general anaesthesia. The study will: * Compare the occurrence of rebound pain and its recovery between a peripheral nerve block of the popliteal sciatic nerve and an ankle block in patients undergoing lower limb (forefoot) bone surgery under general anaesthesia combined with a PNB achieved in preoperative single injection. * To identify the role of the type of nerve fibers anesthetized and the local inflammatory process in rebound pain development. * Assessing the amount of the local sympathetic block induced by the locoregional anesthesia could be used a non-invasive predictive indicator of the occurrence of rebound pain depending on the nerve fibers involved (purely sensitive versus sensitive and motor).