Your hip is a ball and socket joint. Normally, the ball at the top of your thigh bone (femur) moves smoothly in the socket of your pelvis (hip) on a lining of cartilage. The cartilage stops the bones from rubbing together. If the cartilage is worn away, the underlying bone is exposed and your joint becomes painful and stiff. As a result walking and moving around becomes painful.
Artificial hip parts can be made of metal, ceramic or plastic. Hip joints can be fixed in place using a special substance called 'bone cement'. Alternatively, they may be designed so that your own bone grows onto the metal. These 'uncemented' hips can be coated with a type of bone mineral (hydroxyapatite) or can be made from a material that has lots of tiny holes (porous coating). This encourages your bone to grow into the artificial joint and fix it in place.
During your original hip replacement, your hip joint was replaced with artificial hip parts. These usually last from 10 to 20 years, after which they need replacing. Renewing an artificial hip joint is more complicated than the original operation because the existing artificial hip joint will need to be taken out before the new one is fitted. If the hip has worn loose then this may not be too difficult for your surgeon, but if it is still bonded to your bone then removing the old components can be a challenge. You may find that your new joint, although a big improvement on your old joint, may not improve your life as much as your original hip operation. This may be because the muscles can take a long time to recover from the build-up of scar tissue and repeat surgery.
Surgery is usually recommended only if non-surgical treatments, such as taking painkillers (eg paracetamol) or anti-inflammatories (eg ibuprofen), or using physical aids like a walking stick, no longer help to reduce your pain or improve mobility. Hip resurfacing may be a better option for people with stronger bones. In this operation the surfaces of the ball and socket are covered with metal caps.
Your surgeon will explain how to prepare for your operation. For example, if you smoke you will be asked to stop, as smoking increases your risk of getting a chest and wound infection, which can slow your recovery. The operation is usually done under general anaesthesia. This means you will be asleep during the operation. Alternatively you may have the surgery under spinal or epidural anaesthesia. This completely blocks feeling from below your waist and you stay awake during the operation. Your surgeon will advise you which type of anaesthesia is most suitable for you. Often people have a combination so that they are asleep, but the spinal/epidural anaesthetic will ease any pain immediately after surgery. If you're having a general anaesthetic, you will be asked to follow fasting instructions. This means not eating or drinking, typically for about six hours beforehand. However, it's important to follow your anaesthetist's advice. Your surgeon will discuss with you what will happen before, during and after your procedure, and any pain you might have. This is your opportunity to understand what will happen, and you can help yourself by preparing questions to ask about the risks, benefits and any alternatives to the procedure. This will help you to be informed, so you can give your consent, by signing a consent form, for the procedure to go ahead. You may be asked to give your consent to have your name on the National Joint Register, which is used to follow up the safety, durability and effectiveness of joint replacements and implants.