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Hip replacement surgery: best materials and procedures

Hip replacement surgery: best materials and procedures

Which Hip Replacement Surgery is best? Which hip prosthesis, meaning hip implant or artificial hip, is best? These are the two questions many people ask when the time comes to consider a total hip arthroplasty – the surgical term meaning total hip replacement surgery. This blog will explore the best materials and procedures for hip replacement surgery.

Most people will be wondering which hip surgery has the best success rate, which are the most successful procedures, and which is the best material to use for a new hip. But the answers can be very different depending on each individual. There is no one glove (or prosthesis) that fits all. We’ll be diving into the detail of everything you need to consider right here.

It should be noted that all other non-surgical options to manage your hip pain, from physical therapy and exercise, weight management, through to other medical options, such as medication and hip joint injections (for example corticosteroid injections) should be exhausted before hip replacement surgery is considered.

Surgical Options for Total Hip Replacement

There are two main surgical options when hip replacement surgery is being considered. You can discuss both with your orthopaedic surgeon so that you can better understand which option is best for you and why. The options are Conventional Total Hip Replacement Surgery and Hip Resurfacing.

Conventional Total Hip Replacement Surgery

This is the most common procedure that will be used during Hip Replacement Surgery.1 It is the traditional hip replacement surgery. This makes up 98-99% of all hip arthroplasty surgeries for hip osteoarthritis.  In a traditional total hip replacement, the head of the thighbone (femoral head) and the damaged socket (acetabulum) are both removed and replaced with metal, plastic, or ceramic components.

Total Hip Replacement Options

 Hip Resurfacing

In a hip resurfacing procedure, the head of the thighbone (femoral head) is not removed.  Instead, it is trimmed and then capped with a smooth metal covering, and the cartilage of the socket replaced with a metal lining Hip resurfacing implants have been in use in various forms for over 40 years, so it is not a new surgery.1 However, it is only an option for appropriately selected patients. Patients have to meet certain criteria to be eligible for the hip resurfacing implants.

Which total hip replacement surgery should you choose?

Two of the biggest factors in deciding on hip resurfacing or conventional hip replacement are age and activity levels. Hip resurfacing is often used in a younger, more active person as it is easier to do revision surgery in later years once the hip implant wears out.

Hip revision surgery means replacing the hip prothesis that is currently in place.  Outcomes of revision surgeries are generally not as good as the first surgery, so the less procedures over your life, the better.

A Conventional Hip Replacement, although still the best option for most, is harder to revise when the hip replacement fails. 

Assuming a long life, all hip replacements will eventually fail, most commonly due to loosening and wear, infection, fracture or dislocation.2 So, the age of the patient and when or whether they are likely to need a revision procedure is an important consideration when deciding what surgery, and when the surgery should be done.

How long does a hip replacement last?

The information available from joint registries have shown:

  • 85% of prostheses last 20-years
  • 58% of prostheses last 25-years
  • Some have even lasted 40 years!2
How Long Does a Hip Replacement Last?

It’s important to note that the materials that were used when these surgeries were done, over 20 years ago, were much inferior to the materials used now. The newer materials are much more hard wearing, so surgeons are anticipating that the life of the prostheses they are using now could be much longer. 

How long a hip prothesis is likely to last will be a factor in the surgical decision making, together with the age of the patient. Someone young who is likely to need their hip revised at some time in the future, may be considered a possible candidate for hip resurfacing.3

Who is suitable for Hip Resurfacing

Up until recently, hip resurfacing was considered as an option for the larger framed male who is less than 65 years of age, so the younger patient.  However, the research is constantly evolving in this newer area of hip arthroplasty surgery, and resurfacing may be an option in some over 65 year old, older patients as long as they meet certain criteria. 

Those who want to be more physically active after their replacement may also want to consider hip resurfacing as a surgical option.

Who is unsuitable for hip resurfacing

Generally, people with hip dysplasia are not suitable for hip resurfacing. People with hip dysplasia are more likely to struggle with hip arthritis but the shallow hip socket that is found in people with hip dysplasia means they are at higher risk of failure with this type of surgery. 

As size of the bone at the top of the femur, the “femoral head size”, is currently extremely important in deciding if hip resurfacing is an option, females with hip arthritis are often not suitable for this type of surgery unless they meet the skeletal size requirements. 

Resurfacing vs Conventional Total Hip Replacement

What are the different Approaches for Total Hip Replacement Surgery

There are usually one of three ways that your hip orthopaedic surgeon (“orthopedic surgeon” in the United States) will actually do your surgery, although other variations do exist. The most common approach is from the back of the hip, known as the posterior approach. Until recently the “anterior approach” was less frequently used, that is, approaching from the front of the hip.  However, this is fast becoming a frequently offered alternative by many surgeons. The lateral approach is the third approach that has been around for some time.

Different Approaches for Total Hip Replacement Surgery

The posterior approach for total hip arthroplasty. 

The surgeon will cut through the gluteus maximus muscle at the back of the hip and detach the deep hip external rotator muscles to view the back of the hip joint.

  • This is the most commonly used approach.
  • Offers the surgeon excellent access to the hip joint.
  • The abductor muscles, or the muscles at the side of the hip are spared. This means patients are less likely to limp in the recovery period than those who have a lateral approach (see below).
  • The sciatic nerve, a large and very important nerve in the back of the hip can be clearly seen, making it easier to protect this structure.
  • The disadvantage of approaching from the back is that there can be a higher rate of dislocation after surgery, compared to other approaches.  However, dislocation rates have been improving over time and some recent studies show rates as low as other surgical approaches. It is always important that post-operative instructions are followed to keep the hip safe in the healing period.
The Posterior Approach for Total Hip Replacement

 The anterior approach for total hip arthroplasty

The anterior approach, or anterior hip replacement, is where the surgeon approaches from the front of the joint. They go through between two of the major muscles at the front of the hip, the rectus femoris and the TFL.

  • No muscles are cut and so no muscles need to be repaired afterwards.As the muscles at the side and back of the hip are not cut, there is less chance of dislocation afterwards so there are less restrictions with what you can and cannot do after your surgery compared with other approaches.
  • Patients often require less time in hospital and can achieve a faster recovery in the early phases, although with improvement in surgical technique and physical therapy post operative routines all approaches generally do well in the long term.
  • As the surgery is performed with the patient lying on their back, the position of the new hip prosthesis can be checked with xray during the hip surgical procedure.
  • The surgeon has to work through a smaller “window” so this is not the typical choice for more complex cases or difficult revision surgery.
  • This approach requires specific training and instruments that may not be available at some hospitals.
The Anterior Approach for Total Hip Replacement

 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.
Direct Lateral Approach for Total Hip Replacement

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.

Individual Parts of a Total Hip Prosthesis

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.
Bearing Surface Options for Total Hip Replacement or Hip Resurfacing

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.

Frequently Asked Questions About Total Hip Replacement Materials

Organ transplant may have a high risk of rejection, however, the risk of your body rejecting the artificial hip implant is exceedingly rare. The materials used in hip replacement surgery are generally well tolerated by the body, many of them with a very long track record!

If your surgery was performed in a public hospital, contact the hospital’s medical records department for the details. These should have been recorded in your operation sheet. If your surgery was performed in a private hospital, contact your surgeon who will hold your records.

Ask your doctor about patch testing pre and post the surgery – this can help detect any allergies. After having the replacement, look for irritation or skin discolouration around the area of the hip, redness or swelling, ongoing pain, a fever or elevated temperature, or stiffness. Should you have any concerns, call your doctor immediately.

Patch testing may help detect any allergies. Signs may include irritation or skin discolouration around the area of the hip, skin irritation, redness or swelling, ongoing pain, a fever or elevated temperature, or stiffness. Should you have any concerns call your doctor immediately.

Metal allergy is a rare cause of implant failure. If you are allergic or sensitive to metal, then it is important to alert your surgeon prior to having joint replacement surgery. Any concerns you have about metal ions in the body, discuss them with your surgeon well before your operation.

Absolutely.  There are several considerations to discuss with your surgeon regarding the type of replacement you have and the materials used. It is also important to inform your obstetrician about your medical history so that they can work with you to plan the best options for delivering your baby.  When it’s time to deliver, remind medical staff attending you about your hip replacement.

There is always a risk of blood clotting after surgery. Discuss this with your surgeon before your surgery to discuss any changes to medication that may be needed. Your surgeon will also talk through their post operative approach to blood clot prevention.

If you are experiencing pain, check out our course and see if it is suitable for you.

Recovering from Piriformis Syndrome, Deep Gluteal Syndrome or Hip Related Sciatica

This blog has aimed to summarise the best materials and approaches for hip replacement surgery.

We strongly advise you seek out the help and advice of a Hip Pain Professional to help find the best option for you. You can find a healthcare provider with a specific interest in hip and pelvic pain in our directory by clicking HERE.

Remember that if you struggle to find a health professional that knows hips near to you, you are now able to consult over video conferencing with most professionals globally.

At Hip Pain Help we are here to help you on your journey to recovery.

Meet our Hip Pain Professionals – Health professionals that know hips

find causes of your hip pain with the pain locator map

Visit our Pain Locator Map to learn more about pain in different regions around the hip and pelvis. 

find causes of your hip pain with the pain locator map

Visit our Pain Locator Map to learn more about pain in different regions around the hip and pelvis. 

Check Out More You Can Read on Hip Pain Relief at HipPainHelp:

Dr. Alison Grimaldi

Authors

This blog was written by Dr Alison Grimaldi and Kirsty McNab, physiotherapists who have over 50 years of combined professional clinical experience, dealing with patients suffering from a wide range of hip and pelvic conditions.

Kirsty McNab

Dr. Alison Grimaldi BPhty, MPhty(Sports), PhD is Practice Principal of Physiotec Physiotherapy, an Australian Sports Physiotherapist and Adjunct Senior Research Fellow at the University of Queensland, author and global educator.

Kirsty McNab BSc Hons, MPhty(Sports), is Practice Principal of Physiologix and a highly experienced Sports and Exercise Physiotherapist having worked extensively with elite athletes, the Olympic Winter Institute of Australia, and Tennis Australia.

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