Modern hip replacements use a metal stem in the thigh bone with a ceramic, oxidised zirconium, or metal ball that articulates with a polyethylene or ceramic liner inside a titanium cup. Mr Shakir Hussain's commonly used systems include the Exeter V40, Corail, C-stem AMT, and Trident. For complex revision and periprosthetic fracture cases, custom 3D-printed implants and proximal femoral replacement are available through the Royal Orthopaedic Hospital.
What Does a Hip Replacement Implant Actually Consist Of?
A modern hip replacement is built from four main parts. Each part does a specific job, and the four together restore the ball-and-socket mechanics of the natural hip joint.
- The femoral stem. A metal rod that fits down inside the femur (thigh bone). It is the anchor for the new joint.
- The femoral head. A smooth ball that sits on top of the stem. It is made of ceramic, oxidised zirconium, or cobalt-chromium metal.
- The acetabular shell (or cup). A hemispherical metal shell that fits into the prepared socket in the pelvis. Most are titanium.
- The acetabular liner. A polyethylene (plastic) or ceramic insert that sits inside the shell. The femoral head moves against the liner; this is where wear happens over time.
Stems and shells are made of titanium or cobalt-chromium alloys. Heads are ceramic, oxidised zirconium, or cobalt-chrome. Liners are highly cross-linked polyethylene or ceramic. The combination chosen depends on your age, bone quality, activity level, and the wear profile your surgeon wants to deliver.
For a walkthrough of how the implants are placed during the operation itself, see the companion article on what happens during hip replacement surgery.
How Is the Implant Fixed to the Bone?
There are three fixation patterns: cemented (held in place with acrylic bone cement), uncemented (press-fitted into prepared bone, where new bone grows into the implant surface over weeks and months), and hybrid (a cemented stem with an uncemented cup, or vice versa). The choice depends on your bone density, age, activity, and anatomy.
This decision is covered in detail on the dedicated page on cemented vs uncemented hip replacement, including the NJR data on long-term survival and how Mr Hussain chooses for individual patients. This article focuses on the implants themselves rather than how they are fixed.
The Bearing Surface: What Materials Touch?
The bearing surface is the interface between the head and the liner, the parts that move against each other every time you walk. It is the most important determinant of how long the implant will last.
Three combinations are in routine modern use.
Ceramic on polyethylene
This is the workhorse bearing of modern hip replacement and the default in most patients over 60. The head is ceramic (smooth, hard, biologically inert) and the liner is highly cross-linked polyethylene (a tough, wear-resistant plastic). The wear rate is very low (under 0.1 mm per year), there is no metal ion concern, and the cost is modest. National Joint Registry data shows excellent durability at 10 and 15 years.
Ceramic on ceramic
The lowest-wear bearing currently available. Both the head and the liner are ceramic. Best suited to younger, high-demand patients, typically under 55 or 60, where preserving implant life over decades matters most. Long-term studies in patients under 30 show lower revision rates compared with other bearings. The small trade-offs are ceramic fracture (rare with modern ceramics) and a small risk of audible squeaking in some patients. Mr Hussain uses ceramic-on-ceramic for hip resurfacing and selectively in younger primary hip replacement patients.
Metal on polyethylene
A cobalt-chromium head running against a polyethylene liner. This combination has a long, reliable track record going back to the 1960s and is still widely used in older patients with cemented constructs. The cost is lower than ceramic options. The trade-off is a slightly higher wear rate than ceramic and a small theoretical concern about metal ion release.
Metal on metal
Largely abandoned for primary hip replacement in modern practice after high-profile recalls related to elevated metal ion release. The exception is hip resurfacing, where the bearing geometry is different and where modern ceramic-on-ceramic resurfacings are now available.
Hip Replacement Implant Brands Commonly Used in the UK
The National Joint Registry records every joint replacement performed in the UK and publishes annual data on which implants are most used and how each performs. The following are the most widely used systems in current UK practice. Mr Hussain personally uses a subset, choosing the right implant for the right patient rather than committing to a single brand.
Stryker
The Exeter V40 cemented stem is the most-implanted stem in the NJR and has been the backbone of UK cemented hip replacement since the late 1980s. Stryker also supplies the Accolade II uncemented stem, the Trident family of acetabular cups (including the cementless Trident II Tritanium and the cemented Trident Contemporary), and Stanmore megaprosthetic systems used in complex reconstruction. Mr Hussain commonly uses Exeter stems and Trident cups in his cemented and hybrid practice.
DePuy Synthes (Johnson and Johnson)
The Corail stem is a hydroxyapatite-coated uncemented stem with a strong long-term track record and is one of the most-used cementless stems in the UK. The C-stem AMT is a triple-tapered cemented stem. The Pinnacle cup is widely used as the cementless cup partner for Corail. Mr Hussain commonly uses Corail and C-stem AMT.
Smith and Nephew
The Polarstem is an uncemented stem that has performed exceptionally well in NJR-tracked constructs when paired with the R3 cementless cup and the OXINIUM oxidised-zirconium head (the POLAR3 system). OXINIUM is a niche head material that combines the smoothness of ceramic with the toughness of metal.
Zimmer Biomet
The Avenir Complete, Taperloc, and CPT stems and the G7 and Continuum acetabular shells are widely used in UK practice. The Avantage dual-mobility cup is selected for patients at higher risk of dislocation, often in revision surgery or in patients with neurological or muscular weakness.
Waldemar Link
The Lubinus SP II cemented stem has an exceptionally long European track record. Link is more relevant to complex reconstruction, where the MP Reconstruction modular cementless stem and the MEGASYSTEM-C megaprosthesis are used.
MatOrtho
British manufacturer most relevant to hip resurfacing rather than primary total hip replacement. The Adept and ReCerf resurfacing systems are MatOrtho products.
Which Implant Will Mr Hussain Choose for Me?
The implant choice is bespoke. Mr Hussain weighs several factors before deciding.
- Your age. Younger, higher-demand patients usually benefit from a longer-lived bearing such as ceramic on ceramic.
- Your bone quality. Osteoporotic bone may favour cemented fixation; strong bone in a younger patient typically suits uncemented fixation.
- Your anatomy. Femoral shape, neck length, and offset all influence which stem family will give the best fit.
- Your activity level. A patient planning to ski, climb, or run benefits from a low-wear bearing.
- Your medical history. Prior hip surgery, metal allergy concerns, and certain neurological conditions all influence the decision.
- The bearing wear profile expected over your projected lifespan.
The discussion happens at your consultation, with Mr Hussain showing you the proposed implant family and explaining why it suits your case. If your hip is unusual or your prior surgery has left abnormal bone, the conversation will extend into the custom implant territory covered below.
How Long Do Hip Replacement Implants Last?
Modern hip replacements are designed to last decades. The most recent National Joint Registry analyses give the following framework for primary hip replacement implant survival.
- Around 95 percent of implants are still in place at 10 years.
- Around 85 percent are still in place at 20 years.
- Survival depends heavily on age, bearing surface, fixation, and activity. Younger high-demand patients have higher revision rates because of wear; older lower-demand patients often outlive their implant.
The numbers will be different if you choose hip resurfacing, where bone is preserved and a future revision is often easier. The numbers are also different for revision implants, where survival expectations are typically lower than for primary surgery.
Implants do not need to be replaced preventively while they are functioning well. The decision to revise is based on symptoms (pain, instability, loosening visible on x-ray) rather than on time elapsed since the original operation.
Custom (Patient-Specific) Hip Implants
A small but important group of patients have anatomy or bone defects that cannot be addressed with off-the-shelf implants. For these patients, a custom 3D-printed implant is designed specifically for the individual's anatomy.
When custom implants are used
- Severe acetabular bone loss after multiple failed revisions, where the pelvic socket no longer offers enough bone to support a standard cup.
- Pelvic discontinuity, where a fracture or chronic loosening has divided the pelvis into two parts that no longer move as one.
- Congenital hip dysplasia with significantly abnormal pelvic anatomy.
- Complex failed revision where conventional augments and reinforcement cages cannot restore the hip's centre of rotation.
Custom implants are also used in orthopaedic oncology for tumour reconstruction. Mr Hussain does not perform tumour surgery; the Royal Orthopaedic Hospital has a dedicated orthopaedic oncology team for those cases. The information below relates to the non-oncological custom implant work that forms part of Mr Hussain's complex revision practice.
How they are made
The workflow is detailed and CT-driven. A high-resolution CT scan of your pelvis is sent to the manufacturer's engineers. A virtual three-dimensional model of your hip is built, the implant is designed around your specific anatomy, and you and Mr Hussain review the planned implant before it is made. The implant is 3D-printed in titanium, machined, and sterilised. Lead time from initial scan to ready-to-implant is typically 6 to 12 weeks.
Manufacturers used in the UK
- Stanmore (now part of Stryker): the UK-developed Stanmore custom implants and triflange acetabular constructs.
- Materialise: the aMace custom acetabular triflange, widely used for severe socket bone loss.
- Implantcast: bespoke pelvic, acetabular, and femoral reconstructions including the Mutars custom range.
Cost and access
Custom implants are an order of magnitude more expensive than standard implants because of the design and manufacturing complexity. In private practice they are quoted on a case-by-case basis. Insurance authorisation usually requires pre-approval with the implant specification and supporting clinical evidence; Wendy Richards can guide patients through the authorisation process.
Proximal Femoral Replacement (PFR)
A proximal femoral replacement is a long modular implant that replaces the entire upper portion of the femur, the femoral head, the femoral neck, and a variable length of the femoral shaft, along with a new acetabular cup. The remaining lower femur is keyed into a long cemented or cementless stem and the abductor muscles, where preserved, are reattached.
When it is needed in Mr Hussain's practice
- Catastrophic femoral bone loss after multiple failed hip revisions, where the proximal femur is so damaged that conventional revision stems cannot achieve fixation.
- Complex periprosthetic fractures where the femur has broken around an existing hip replacement and is not reconstructable with conventional techniques.
PFR is also used in orthopaedic oncology for primary bone tumours and bone metastases. As above, Mr Hussain does not perform tumour surgery; ROH's orthopaedic oncology team manages those cases.
Main PFR systems
The systems in current UK use are MUTARS (Implantcast), MEGASYSTEM-C (Waldemar Link), GMRS (Stryker), and Stanmore METS (Stryker, formerly Stanmore Implants). Mr Hussain chooses the system that best matches your anatomy, your bone quality, and the implant's modularity options for your specific reconstruction.
Realistic outcomes
PFR is major surgery and the expectations are different from primary hip replacement. Realistic figures:
- 10-year implant survival around 70 to 75 percent.
- Dislocation rates higher than primary hip replacement (around 10 percent), driven by the loss of normal abductor muscle function. Dual-mobility cups and constrained liners are often used to lower this risk.
- Deep infection rates around 5 to 7 percent, higher than primary hip replacement.
- Most patients regain independent mobility, usually with a walking aid such as a stick or crutch.
Modern modular designs, dual-mobility bearings, and improved trochanteric reattachment techniques have improved these numbers since 2010.
How Complex Revision Cases Are Planned at the Royal Orthopaedic Hospital
The Royal Orthopaedic Hospital Birmingham is a leading specialist orthopaedic hospital in the UK. For complex revision and proximal femoral replacement cases, the planning depth available at ROH is one of the practical advantages of Mr Hussain operating there.
- High-resolution CT and MRI scanning to characterise the bone defect in three dimensions.
- 3D-printed anatomical models for cases where pre-operative visualisation of the bone supports the surgical plan.
- Direct collaboration with implant manufacturers' engineering teams during the design of custom implants.
- An on-site implant supply chain that holds modular revision stems, augments, dual-mobility cups, and PFR components for intra-operative flexibility.
For each complex case, Mr Hussain plans the operation in detail before the day of surgery and discusses the planned approach with you at consultation. Patients undergoing custom implant or PFR surgery typically see Mr Hussain two or three times before the operation, and the planning often involves the manufacturer's engineers as well as the surgical team.
Frequently Asked Questions
Will my hip replacement implant set off airport security?
Sometimes, yes. Modern body scanners may detect the metal in the stem and cup. Carrying a copy of your post-operative letter helps. Mr Hussain's secretary can provide a discreet implant card on request.
Will an MRI scan still be possible after hip replacement?
Yes. Modern hip implants are MRI compatible, although image quality close to the implant is reduced. Inform the MRI department before the scan that you have a hip replacement so the protocol can be adjusted.
What metals are used in hip replacement, and what if I have a nickel allergy?
Modern hip stems and cups are made of titanium or cobalt-chromium alloys. True nickel allergy affecting joint replacement is rare. If you have a documented metal allergy, Mr Hussain may choose an alternative implant (such as titanium-only constructs or ceramic-on-ceramic bearings) and may arrange specialist allergy testing in advance.
Will I be able to feel the hip replacement implant?
Most patients do not feel the implant once recovery is complete. Some patients describe a faint awareness of "something there" in the first year, which usually fades.
What happens if a hip replacement implant wears out or loosens?
The implant is revised, meaning the worn or loose components are removed and replaced. Modern revision surgery is well established. Earlier signs of implant wear often allow a partial revision (for example, exchanging only the polyethylene liner) rather than replacing the whole implant.
Is a hip replacement implant ever replaced preventively?
No. The decision to revise is based on symptoms and on x-ray evidence of wear or loosening, not on time elapsed since the original operation.
Can I have a knee replacement if I already have a hip replacement?
Yes. The two operations do not interact. Many of Mr Hussain's patients have a hip replacement on one side and a knee replacement on the other, sometimes performed by Mr Hussain himself.
Mr Shakir Hussain
Consultant Hip and Knee Surgeon at the Royal Orthopaedic Hospital Birmingham. Specialist in hip resurfacing, hip replacement, robotic knee replacement, and complex revision surgery.