What is a Hip hemiarthroplasty?
A hip hemiarthroplasty is similar to a hip replacement but only one half of the hip joint is replaced. In a hip hemiarthroplasty the top of the thigh bone (femur) is replaced by a metal implant.
The hip joint is a ball and socket joint. The socket is formed by a cup in the pelvis, known as the acetabulum. The ball of the joint is formed by the head of the thigh bone (femur). The top part of the thighbone, just below the head, is called the neck of the femur.
A hip hemiarthroplasty may be required if the neck of the femur has been fractured, particularly if the break is close to the hip joint. If the fracture is very close to the hip joint, the blood supply to the head of the femur may be disrupted. In this case, even if the fracture healed, the head of the femur will just crumble away due to lack of blood supply.
When the hip is fractured, the socket portion (the acetabulum) is usually not injured. If the cartilage of the hip socket is in good health, the metal ball of the hemiarthroplasty can glide against the cartilage without damaging the surface. This operation is easier to do than replacing both the ball and the socket (total hip replacement), and it allows patients to begin moving soon after the surgery. This helps prevent complications that can arise due to long periods of bed rest.
Who is this operation for?
A hemiarthroplasty may be required if you have broken your hip. Not all hip fractures require a hemiarthroplasty. If the break is lower on the neck of the femur or if the break has not disrupted the blood supply to the head of the femur then the fracture may be fixed using a dynamic hip screw or other implant systems.
Hemiarthroplasties are favored as treatment for hip fractures in the following situations:
- the fracture has disrupted the blood supply to the femoral head: in this case even if the fracture heals, the head of the femur will crumble. This is known as avascular necrosis and will lead to the hip joint failing.
- severe osteoporosis: if the bone is too brittle, other methods of fracture treatment will not be successful
- a fracture that has been present for several days
Hemiarthroplasties CAN NOT be performed if there is:
- osteoarthritis of the acetabulum: if the hip socket (or acetabulum) is worn out or damaged due to osteoarthritis, then a hemiarthroplasty will not succeed. In this case a total hip replacement may be required.
- a pre-existing infection: if there is an infection in or around a hip, then a hemiarthroplasty can not be performed
Complications
A hemiarthroplasty of the hip is a serious operation and like all surgery is associated with certain risks. The complications associated specifically with this operation include:
- Fracture of the femur: as part of this operation, there is a risk that whilst the ball of the femur is being replaced by a metal implant, the lower part of the femur may break. This is a rare complication, occurring in under 5% of cases
- Dislocation: once the operation has been performed, dislocation can occur more commonly than in a hip that has not been operated on. It is important that you follow instructions provided by your surgeon and physiotherapist in order to ensure these risks are minimised
- Infection: following any operation, there is a risk of infection
- Loosening of the implant: the metal hip implant may become loose and cause hip pain and wearing of surrounding bone. If this occurs, a further operation may be required to ensure recovery.
- Pain: in some cases, the arthroplasty may result in prolonged pain in the hip area. This may require a further operation, usually a total hip replacement in order to fix the problem.
There are general complications of any surgery. These include:
Before the operation
This operation is usually an emergency surgery resulting from a hip fracture that often results from a fall. For this reason it is likely you may not have had time to plan and prepare.
If you come in to the Emergency Department, the ED doctors will make sure you are stable. They may give you some fluids and oxygen as well as pain relief, before sending you to get X-Rays of your hip.
The orthopaedic surgeons will need to see you to assess your injury and your general health before deciding if you can be taken straight to surgery. Some tests that may be ordered to check that you’re fit for surgery include:
- Blood tests
- Chest X-Ray
- Urine test
- ECG
You will be asked not to eat anything until the plan for surgery is confirmed. In the meantime, you will be kept comfortable and possibly taken up to the ward.
Make sure you tell your doctor if you:
- Have heart, lung or blood conditions
- Have ever taken cortisone, prednisolone or other steroids
- If you are taking warfarin or aspirin
Ideally, a caregiver, such as a family member or friend, will help make arrangements for you while you are in the hospital. The surgeon and care team will communicate with your caregiver to help with these preparations.
About the Operation
Anaesthesia
The anaesthetic team will see you and decide the type of anaesthetic that’s best for you. The different types of anaesthesia include:
- General Anaesthetic: This type of anaesthetic puts you asleep during the whole procedure and a machine controls your breathing.
- Spinal Anaesthetic: An injection is placed into your back to numb your hip and legs. You will be awake during the procedure, however a sedative can be given to you to help you doze off.
- Nerve Blocks: This special injection is used to help with your pain after the operation and often used in conjunction with a general anaesthetic.
The prosthesis
A prosthesis is a medical term for an artificial joint replacement. In hip arthroplasty, the prosthesis is composed of a metal stem that fits into the top of the thigh bone and a metal ball that fits into the socket of the hip joint.
The ball on the prosthesis may be solid metal known as a unipolar design. Another design allows the ball to swivel and is known as a bipolar prosthesis. The bipolar model was designed to try to reduce the wear and tear on the cartilage of the hip socket. It is unclear whether the swivel design actually provides less wear and tear. Both designs are effective.
The prosthesis may be held in place with a special type of cement which attaches the metal to bone. Another option is that the prosthesis has a fine mesh coating which allows the bone to grow into the mesh securing the implant in place. This is known as an uncemented prosthesis. The decision about whether to use a cemented or uncemented prosthesis is usually made by the surgeon based on your age, the condition of your bones, and the surgeon’s experience.
The Operation
To begin with, the surgeon makes an incision on the thigh to allow access to the hip joint. Once the hip joint has been exposed, the surgeon removes the head of the femur from the socket.
The stem of the prosthesis is then inserted into the femur. The metal ball that makes up the femoral head is then attached.
Once the implant is in place, the new artificial hip is put back into the hip socket. The surgeon will then make sure the hip is working properly before he closes the incision using stitches or staples.
Recovery Room
After the operation, you will be resting in the recovery room, where specially trained nurses will closely monitor you. This usually takes 1 to 2 hours. After this time, you will be taken to your hospital room.
After the Operation
Your Stay in the Hospital
You will usually stay in the hospital for a few days.
After surgery, the site of the incision will be covered with a dressing. Special boots or stockings are placed on your feet to help prevent blood clots from forming. To protect your hip during early recovery, a special triangular splint may be placed in-between your legs to keep them apart.
How much will it hurt?
After surgery, you will feel pain in your thigh.
If you have been given a spinal injection during your anaesthetic, your legs may be numb for the first 12 hours.
Pain medication, either tablets or injections, will be given to make you as comfortable as possible.
What exercises do I do whilst in hospital?
- Breathing: To avoid lung problems after surgery, you will be asked to breathe deeply and cough frequently. This will help avoid pneumonia and lung collapse.
- Walking: Walking and light activity are important to your recovery and will begin the day of or the day after your surgery. Most patients who undergo total hip replacement begin standing and walking with the help of a walking support and a physiotherapist the day after surgery.
The physiotherapist will teach you specific exercises to strengthen your hip and restore movement for walking and other normal daily activities.
How long will I stay in hospital
Patients are usually able to go home after spending 4 – 7 days in the hospital. You are ready to go home when you can safely get in and out of bed, walk up to 20 meters with your crutches or walker, go up and down stairs safely, and understand your hip precautions. Patients who still need extra care may be sent to a different hospital ward for further rehabilitation before they go home.
Recovery and Rehabilitation
Wound Care | How do I look after my wound?
It is important to keep your wound as dry as possible.
Most patients are discharged home with a waterproof dressing, which can be left on for showering.
During the first 24 hours, it is normal to have some minor bleeding. After being discharded home, there should be no discharge, redness or bleeding around the wound.
If there is redness, discharge or a foul odor, please seek medical attention as soon as possible.
Wound Care | When will my stitches be removed?
There are a number of ways your wounds may be closed.
You may have either have
- nonabsorbable stitches
- absorbable stitches
- surgical staples
The stitches or staples are usually removed 10-14 days after surgery.
Diet | What should I eat and drink?
There are usually no specific diet or extra vitamins / nutrients needed to recover from a total hip operation.
It is important to have a normal healthy balanced diet and plenty of nonalcoholic fluids.
Activity | What exercises should I do at home?
Physiotherapy and the exercises that you perform at home are extremely important to achieve the best results after a hip replacement.
After returning home, you should gradually be able to do more and more. It is important to look after your new hip and follow your surgeon’s and physiotherapy instructions.
Your program may include exerises that work on your:
- walking
- sitting
- stair climbing
- muscle strength
For more information on the exercises that are appropriate for this operation see the section on Exercises After Hip Replacement
Avoiding Falls
A fall during the first few weeks after surgery can damage your new hip and may result in a need for more surgery.
Be careful on Stairs. Stairs are a particular hazard until your hip is strong and mobile, and you’ve regained your balance. You should use a walking aid such as cane, crutches or a walker. Use the handrails on your stairs or ask for someone to help you.
Special Precautions
One of the possible complications of hip replacement surgery is dislocation. Dislocation is most common during the first year after surgery, but can occur at any time. There are certain positions and precautions that must be avoided.
- Do not cross your legs.
- Do not bend your hips more than a right angle (90°).
- Do not turn your feet excessively inward or outward.
- Do not twist on your operated leg when turning
- Do not bend down to pick things up off the floor