In all three operative techniques the patient is admitted on the day before or even the same day of the operation. The duration of the surgery is one to one and a half hour. All patients receive epidural anaesthesia, thus the post-operative pain is eliminated. Depending on the characteristics of the patient, the aim is to get mobilize even the first post-operative day, with the assistance of a physiotherapist. The mobilization for the first six weeks is done with crutches. The patient can return to almost all physical activities three months after the operation.