 Hallux surgery is known to be extremely painful. Standard pain therapy is treatment with NSAID and opioid painkillers. Patients are frequently not-satisfied with this. Some institutions use a nerve block single shot or catheter technic of the ischiadic nerve. But this procedure is invasive, has a potential risk of nerve lesion, and is not accepted by all surgeons. A single shot nerve block of the posterior tibial nerve is less invasive and could be superior compared to standard pain treatment. A great variability of nerve supply of the foot is well described. There are some hints that the posterior tibial nerve supplies the first metatarsal bone and the first metatarsal joint. A nerve block could reduce postoperative pain in hallux surgery. To assess the effectiveness of this investigated measure, the requested morphine dose of a PCA pump will be used to verify the effectiveness of the tibial nerve block. 