Direct lateral approach for hip arthroplasty.
The Lateral Approach is where the hip replacement surgery is performed by the orthopedic surgeon from the outer side of the hip. The surgery involves temporarily detaching the muscles at the side of the hip from the top of the thigh bone (femur). These are the abductor muscles – the gluteus medius and gluteus minimus muscles. These two muscles help you to balance your pelvis on your thigh bone when you stand on one leg. They also help to lift the leg up to the side. The muscles are reattached to the bone once the prosthesis is in place.
- The back of the hip is protected so there is less chance of dislocation of the replaced hip out the back of the hip joint.
- However, it takes time for the repaired abductor muscles to heal.
- This means that walking may remain a little more difficult for several months after surgery. This varies between individuals.
- Crutches or a walking aid may be needed for longer to provide support when walking.
- In rare cases, a permanent limp may result due to impact on the abductor muscles or from damage to the nerve that serves these muscles. The risks of this happening are very low, but this is a risk specific to this surgical approach.
What is the best type of hip replacement implant to use?
Choosing which type of conventional hip replacement to have is a bit like trying to buy a car. There are many options and many factors taken into account to decide which implant may be most suitable for you. . Below we will look at all the different types of hip implants.
The individual parts of a total hip replacement implant
Let us first understand what the parts of a standard total hip replacement implant are. Typically, the hip implant (hip prosthesis) is made up of approximately four individual components, 2 parts on the pelvis, or acetabular side and 2 parts on the upper thigh bone, or femoral side.
Pelvic components
- Cup—inserts into the pelvic bone
- Liner—inserts into the cup—essentially becomes your new cartilage
Femoral components
- Stem—inserts into the femur or thigh bone
- Ball—fits onto the end of the stem
Two main categories of total hip replacement surgery
Now that you understand the parts of a hip replacement prosthesis, let’s talk briefly about the two main methods of fixing the implant into the body.
1. Cemented
This means a form of grout is used to bond the implant to the bone.
2. Uncemented
This means that no grout is used. Instead, the bone will grow directly onto the implant. This bone growth is what makes the implant stick. Generally, the stem of an uncemented prosthesis that attaches to the top of the thigh is made of titanium
Titanium is well tolerated. It is not associated with allergy, and it bonds well to bone.
The downside of titanium is that it is relatively soft, therefore other materials are used for the weight bearing parts of the implants.
Type of material used on the weight bearing surfaces of a hip implant
The ball
As we mentioned above, the ball and stem replace the top of the thigh and femoral head. The ball can come in varying sizes that relate to the size of the cup implant chosen for use in the pelvis. The ball can be made of different materials.
- Ceramic – this is a very hard surface, extremely resistant to scratching or damage. A ceramic head, or ball, can be paired with a ceramic or plastic liner in the pelvis.
- Polyethylene – this is a plastic-type material that has evolved considerably over the years. It is now extremely wear-resistant. As a result, most prostheses have some polyethylene component.
- Combination – the Dual Mobility Implant. This is made up of both a ceramic inner ball and a second polyethylene bearing surface over the top, which rotates freely over the inner ceramic ball.
- Cobalt-chromium – also a hard-wearing surface. The metal ball was typically paired with a metal or plastic liner in the pelvis. However, concerns over potential reactions and problems with metal debris from the metal parts when paired with the metal liner, mean that this type of ball is now more commonly paired with a plastic liner in the pelvis.
The acetabulum or pelvic part of the implant
The pelvic part of the hip prosthesis implant is referred to as the “acetabular component”, meaning the “socket” of the hip joint. The socket implant is often made of two parts.
A titanium metal shell is used, which as we mentioned above is great for the bone to grow onto but not so good at weight bearing.
A weight bearing liner is then used that matches the size of the ball. This may be made of different materials.
- Ceramic – this is a very hard-wearing materiel. A ceramic on ceramic is a term you may hear, meaning both the ball and the socket implants are made of ceramic material.
- Polyethylene – as we discussed above, this is a highly wear-resistant type of plastic.
- Cobalt Alloy – this is a hard-wearing resistant metal, often used in the dual mobility implant.
Which type of Hip Replacement should I have?
In summary, there is no one glove fits all. Your Total Hip Replacement surgery should be customised to you and your individual requirements. Your orthopaedic surgeon will consider many things, including:
- your frame size,
- the size of the bones of your hip,
- your gender,
- your age,
- your bone density (how strong or weak your bone is),
- the stability of your joint,
- the length of your soft tissue structures,
- any complications that may exist,
- what you want or need your hip to do, and
- how active you are.
Make sure you discuss your options with your surgeon and understand what type of surgery and implant you are having, why and what it means in both the short and long term. Being able to continue to perform your normal daily activities is important to help you have a good quality of life after the surgery. Again, make sure you discuss these with your surgeon.
Physical Therapy and Total Hip Replacement
Pre-operative physical therapy can better prepare you for surgery, if you still have some time before your operation. This might be just a couple of appointments to learn about what to expect after surgery and familiarise you with the post operative exercises. You may want to see an occupational therapist to help you understand what changes you can make around your home to make your recovery time easier after the surgery.
If you have more time before surgery, engaging in 6-12 weeks of pre-operative conditioning with a physical therapist can help make sure you are best prepared for your surgery and post-operative rehabilitation.
After surgery, make sure that you complete all your physical therapy treatment for the best possible outcome. Rehabilitation may need to go on for longer if you have any complications or major problems, and also if you have more specific requirements from your hip, for example, to achieve a higher level of involvement in activity or sport. Your physical therapist will help you to achieve the long-term results you want out of your hip.
You can find a physical therapist or physio who knows hips, at our Hip Pain Help “ Find a Professional” Directory.