Total hip replacement is one of the safest and reliable operations performed, not just in orthopaedics but across all surgical subspecialties. Over 50000 total hip replacements are done in Australia every year. Most total hip replacements are done for osteoarthritis of the hip but it can also be done for rheumatoid arthritis, necrosis of the ball joint and fracture of the neck of the femur.
Procedure
After making the approach to the hip joint, the surgeon makes a cut through the neck of the femur, removing the ball from the ball and socket joint. The surgeon will then remove the cartilage from the socket with a circular reamer. The new metal hip is then placed into the femur and into the acetabulum and the wound is closed. Generally, this procedure takes about an hour of surgical time.
Components
The components may be held into the socket and femur in one of two ways. They may be cemented in with bone cement. It is very uncommon to require bone cement on the socket side, but bone cement is used very frequently on the femur side. A hole is created within the femur, which is filled up with liquid bone cement. The metal hip is then gently placed within this bone cement and the cement is allowed to harden.
Your surgeon may also choose a non-cemented implant. On the socket side the cartilage is reamed down until there is bleeding bone underneath. A metal socket is placed into the existing bony socket, hard up against the bleeding surface of the bone. The metal socket is generally made of titanium, with a rough surface which allows the bone to grow onto it, thus becoming part of the patient. The titanium socket is then lined with polyethylene or a ceramic liner.
With an uncemented femoral component, a hole is made at the top of the femur and the titanium component is knocked into the femur and held hard against the bleeding bone. Again, the bone will grow onto the rough surface of the titanium femoral shaft, becoming integrated into the patient’s bone.
Hip Replacement Anaesthesia
Hip replacements can be done under general anaesthesia or regional anaesthesia. The most commonly used regional anaesthesia for hip replacements is a spinal block. With this technique, you would be wheeled awake into the operating theatre and cold antiseptic would be placed on your back. The anaesthetist would pass a small needle next to the spinal cord and inject local anaesthetic and painkillers to make the nerves in the spine go numb. It is possible with this technique to remain awake during the surgical procedure, however most patients opt to be sedated and to sleep through the operation. Once the anaesthetist has confirmed that the spinal block has worked, medication is given through a drip to drift you off to sleep. Once the surgery has been completed, the anaesthetic through the drip is stopped and you are wheeled through to recovery. Over the next few hours, the spinal block wears off, allowing you to move your legs and feet. At this stage, as the sensation returns, discomfort or pain from the surgical site will begin and nurses in recovery or on the ward will administer oral painkillers to make you comfortable.
Rehabilitation
Some patients will stand up on the day of the operation and most patients are walking short distances the following day. Physiotherapists will guide you through your rehabilitation, with most patients progressing from using a walking frame, to crutches. The physiotherapists on the ward will teach you exercises to continue on with once you have been discharged from hospital. Some patients choose to continue seeing a physiotherapist for a few months after the surgery to aid in strengthening the hip and improving walking.
Length of Stay
The length of stay following hip replacement varies greatly from patient to patient. Some patients stay less than 24 hours, while others require lengthy in-hospital rehabilitation on the rehabilitation ward. Most patients stay between 3-5 days following the surgery.
Return to Function
Again, return to function varies greatly between patient to patient. Some patients are off crutches within the first week, while others require a crutch to walk well for the first couple of months. Some good general advice following hip replacement is that you are always better off walking well with a crutch, than walking badly without one. Most surgeons will be happy for you to come off crutches as you feel confident or under the guidance of your physiotherapist. Your surgeon will let you know if there is a specific reason you should continue on crutches for a set time.
Hip precautions: your return to normal activities and your return to work will be directed by your surgeon.
Driving After Hip Replacement
Licensing authorities do not specify any specific driving restrictions after hip replacement. A patient should only return to driving when they can safely brake in an emergency situation. Again, this varies from patient to patient and you should discuss this with your surgeon. Most surgeons are happy for their patients to begin driving at six weeks post-surgery. For more information, please read the Arthroplasty Society of Australia’s statement on return to driving after hip and knee replacement.
