Surgery consists in extracting the head of the femur and preparing the cavity in which it is housed, scraping the surface of this cavity. Then the damaged joint is replaced with an artificial joint having a similar shape and performs a similar function. This surgery requires several days of hospitalisation during which any possible complications that may arise will be controlled. Anaesthesia can be general, although usually a “spinal” type is used by means of an injection in the back which eliminates sensitivity in the legs and immobilises them, whilst the patient remains awake or slightly sedated. About 48 hours after the intervention the drainage is removed, in those cases in which it was used during surgery. After removing the drains, the patient can start walking, sometimes with the help of 1 or 2 walking sticks in order to partially relieve the leg that was operated to minimise pain and accustom the patient to walk with his/her new prosthesis. After the patient is released from hospital, home treatment usually consists of daily injections of “low-molecular-weight heparin” for at least 1 month, together with a treatment with analgesics and/or anti-inflammatory drugs to control the pain. The points of suture or the staples are usually removed 2 or 3 weeks after surgery. In general terms, pain usually disappears 3 to 4 weeks after the surgery, although some discomfort may persist for longer periods of time. These are usually controlled with oral pain-killers.