Inclusion Criteria:  any ambulatory upper limb bone surgery carried out under axillary PNB  Exclusion Criteria:  Refusal to participate Contraindication to the use of ketamine Contraindication to regular use of postoperative analgesics like non-steroidal anti-inflammatory drugs and paracetamol Pregnant woman Diabetic patient Vascular patient Cognitive disorders Inability to answer perioperative questionnaires (language problem)