Hip replacement materials are constantly evolving, with small yet significant advances in material science translating directly into improved longevity and patient outcomes. The common belief that hip replacements only last 10–15 years is an outdated myth - current evidence shows that modern implants demonstrate exceptional durability well beyond 20 years.
From Past to Present
The field of orthopaedic biomaterials has undergone remarkable transformation over the past two decades. Early hip replacement implants, made from simple steel and early-generation plastics, had genuine limitations in wear and longevity. But material science has advanced dramatically.
Modern hip replacements use sophisticated alloys - titanium-based materials that offer superior biocompatibility and osseointegration (the ability of bone to grow directly onto the implant). Ceramic components are now highly refined and extremely hard, minimising wear. The bearing surfaces have been optimised for longevity and friction reduction.
"Material advancements, combined with better surgical technique, explain why we now see hip replacements lasting 25–30 years routinely."
- Dr Chien-Wen LiewWhy Material Selection Matters
The longevity of any hip replacement depends not only on the quality of the materials but also on surgical technique, implant selection, and patient-specific factors. Different surgical approaches and implant combinations have different wear profiles and long-term outcomes.
I choose material combinations and prosthesis designs based on individual patient anatomy, age, activity level, and bone quality. The material selection is both surgeon-dependent and patient-specific - what is optimal for one patient may not be ideal for another.
Dr Chien-Wen Liew explains the metals, ceramics and plastics used in a total hip replacement and how the implant bonds to bone.
Read transcript
0:00 · Start
Hi, I'm Dr Chien-Wen Liew from Adelaide, South Australia. I work at Orthopaedics 360 and I'm a hip and knee replacement specialist. Today, I'd like to go over a little bit about what a hip replacement is actually made of. Now, today, I can only talk about the hip and knee replacements that I place in. But there is a vast number of different materials that they can be made of.
0:28 · What I perform
Now, the hip replacement that I perform is one that I perform using the direct anterior approach. We won't go into this very much into detail today. But it is an approach to the hip, where we do not cut or detach any of the tendons or muscles to approach the hip. When we place the prosthesis, any prosthesis can actually be placed in this way, however, we choose to place one which is specifically made to be placed with the direct anterior approach.
The hip replacement that I place in is one with very good results. We follow all of our hip replacements on the Australian Joint Replacement Registry, which tracks and follows every joint replacement for the hip and knee. That has been placed in for over the last 20 years and enables us to track and challenge any of the prosthesis that have come about. As all of them, well, almost all of them, should be tracked in that system.
1:22 · Biological fixation vs Cementation
The hip replacement that I place in is one that does not generally utilise cement, so we are trying to achieve biological fixation to the implant. What that means is that the implant has been designed to have a coating around it that allows in-growth of bone onto it. Now, that particular structure is called hydroxyapatite. In essence, it's like artificial bone it has very small pores or holes within it of approximately five microns in size.
The hydroxyapatite is coated over majority of the stem and the socket. And over the first 6 to 12 weeks, bone grows are in and onto that substance, strengthening that bond between the bone and the implant. The actual metal of the implant is made of niobium vanadium titanium alloy. It is a very strong alloy and implant breakage is rare. When you place the metal inside the body, there is a very slight flexibility or elasticity to the metal.
And that was designed to avoid having too stiffer construct. Which in the past was translated to potentially causing people to have some thigh pain at the tip of the stem. Now, with this particular design, there are very many different sizes, as well as different lengths and offsets. What that means is that we're trying to replicate what the native anatomy of a patient is. And we have several permutations or options that we are allowed to choose that allow us to replicate a patient's anatomy.
When we perform the surgery, I like to perform all of my operations using something called patient specific technology. Which is where we actually perform a three-dimensional scan on the hip before the surgery, so we know the exact dimensions, position, shape and size long before the operation is performed, that gives me the option to alter or accept the anatomy that you have. It also allows us to select the correct prosthesis before we even come into the operating theater and to identify any anatomical abnormalities which we may need to account for.
The actual articulating part constitutes the ball and the liner The ball and the liner of a hip replacement can either be made of metal, ceramic or plastic. In general, the ball is either metal or ceramic, and the liner is either metal, ceramic or plastic. The options that I utilise are a ceramic ball and either a plastic or a ceramic liner. Now, ceramic on ceramic has been an articulation which has gained a lot of favor due to the fact that it is quite an inert substance in the past.
4:11 · Historical Plastics
And this is a long time ago. The plastics which were first generation were certainly of, not of the quality of current plastics or ceramics. This means that as the plastics used to wear out, the body used to remove those plastics. And cause a white blood cell response. That could get between the implant and the bone, causing quite a large amount of bone loss. This turned into quite a difficult revision scenario, some of which are still being done today, but we are seeing a decrease in those catastrophic revisions, or very difficult revisions.
As the advent of more advanced materials have come about. In today's current materials, we are unlikely to see the same large revisions that we have been performing for those done many, many decades ago. As part of the implant, then there are other foreign materials placed during the surgery.
5:06 · Closing suture materials
That includes the suture material that we use to close the skin. Because we aren't cutting or detaching any of the tendons or muscles, we do not require to repair any of those structures at the end of the operation. The only sutures that I use during the surgery is to close the layers to prevent any potential sites of infection or tracks for infection. But also to create a closure that enables the skin to heal very, very finely.
We use a series of special dressings over the wound to decrease the risk of any gaping or gapping of the wound. And our aim is to provide a wound that is extremely small and very, very thin and very, very unnoticeable in the future. As far as materials go for the rest of the hip replacement, there aren't really any other foreign materials that are placed in during the surgery.
5:58 · Can you feel a hip replacement?
And for those patients who wonder whether they can feel the hip replacement after surgery, I would say that most of our patients feel that the hip replacement is barely perceptible, if at all. After the operation, certainly, the end result is to give you a forgotten hip, and that means you do not think about that hip doing all the activities that you want. After the operation, I hope that's giving you a little bit of insight into what a hip replacement is made of.
There are certainly many other materials that it can be made of, and I'll detail a few of those in the description below. However, for me, this is what I commonly use and I hope you found it useful. Thank you for tuning in and I hope to see you next time.
Transcript edited lightly for readability.
What The Registry Shows
The Australian hip replacement registry and international data consistently show that while the total number of hip replacements performed worldwide is increasing, the revision rate - the percentage of implants requiring replacement - is actually decreasing. This is direct evidence that material advancements are working.
The current Australian data indicates that approximately 92% of hip replacements remain in situ without revision by the 20-year mark. With the newer material combinations and surgical techniques I employ, early results suggest even lower revision rates. These are reassuring numbers that reflect the success of modern hip replacement materials and techniques.
Longevity You Can Count On
Many patients have heard that hip replacements only last 10–15 years and must be revised thereafter. This information is outdated and does not reflect current reality. That timeline applied to much older implant technology and earlier surgical techniques. It was a reasonable statement 20 years ago, but it is no longer accurate.
Modern hip replacements frequently last 25–30 years, and many last even longer. The combination of advanced materials, improved surgical technique, and patient-specific planning means you can have realistic confidence in the longevity of your new hip. While revision surgery is always a theoretical possibility, it is not the expected outcome with current technology and techniques.
Orthopaedic Surgeon, Adelaide
Frequently Asked Questions
Download Materials Guide
A detailed explanation of hip replacement materials, bearing surfaces, and longevity expectations.