Ceramic Bearing Surfaces in Arthroplasty

Ceramic bearings buy the lowest wear rates available in joint replacement and pay for them with brittleness. Alumina and zirconia are both extremely hard and wear-resistant, and modern alumina matrix composites such as BIOLOX Delta set out to keep that hardness while making the material tougher. Everything on this page follows from those two properties pulling in opposite directions.

Where this sits. Ceramic is one option among several, and the comparison that decides the case is made on THA bearing surfaces; the physics of why a smaller, harder particle matters at all is wear mechanisms, and the reason low wear is worth any fracture risk is that osteolysis is particle-driven.

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The bonding. Ceramics are held together by ionic bonds - electrostatic attraction between Al3+ and O2- ions - with partial covalent character, the shared electrons adding to bond strength. Those bonds do not permit dislocation motion, so the material cannot deform plastically. That single fact makes it extremely hard, and makes it brittle.

The crystal. Alumina takes the corundum structure, the same lattice as ruby and sapphire, with oxygen ions in a face-centred cubic arrangement and aluminium ions filling two-thirds of the octahedral interstitial sites; pure Al2O3 is colourless.

Zirconia is polymorphic, and which phase it is in decides how it behaves.

• Monoclinic - stable at room temperature, brittle
• Tetragonal - metastable and tougher, stabilised by yttria (Y2O3)
• Cubic - high temperature only, less relevant here

Transformation from tetragonal to monoclinic carries a 3-5% volume expansion, which is both the reason zirconia can be toughened and the reason pure zirconia bearings failed.

The grains. A ceramic bearing is millions of individual crystalline grains, and the interfaces between them - grain boundaries - are the weak points where cracks start. Grain size is therefore a critical quality parameter, the one that determines the mechanical properties: pure alumina must be under 2 microns (ideally 1-1.5), and the alumina phase of BIOLOX Delta is under 0.5 microns. Components are rejected if the mean grain size exceeds those figures, and scanning electron microscopy is used to measure the distribution.

The composite. BIOLOX Delta is an alumina matrix with a second phase engineered into it rather than a new ceramic. The alumina carries the load and provides the hardness; the zirconia platelets exist to stop cracks; the two oxide additives do jobs that have nothing to do with bearing performance.

How the platelets work. They are randomly oriented through the matrix, so an advancing crack must navigate around them along a longer, tortuous path, dissipating energy as it goes. The stress at the crack tip also triggers the tetragonal-to-monoclinic transformation locally, and the 3-5% expansion that follows puts the crack tip in compression and opposes its opening. Together these raise fracture toughness by about 50% over pure alumina without any bulk phase change.

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Manufacturing. The route from powder to implant is designed to remove the two things that start cracks, porosity and large grains. Ultra-pure alumina powder - quoted as 99.99% pure as raw material, with the finished ceramic at 99.7% - is wet-milled in ethanol for 24-48 hours with the Y-TZP, chromium oxide and strontium oxide so the phases are evenly distributed, then calcined at 1200C to drive off binders and volatiles.

• Cold isostatic pressing at 200-400 MPa forms a fragile "green body" of only 50-60% relative density, pre-sintered at 1000-1200C so it can be handled
• Sintering at 1600-1800C for 2-4 hours densifies it by diffusion; grains grow at this stage, which is what the chromium oxide is there to limit
• Hot isostatic pressing at 1400-1600C under 100-200 MPa of argon for 2-4 hours removes the residual porosity, reaching over 99.9% of theoretical density and eliminating every pore above 1 micron
• Diamond machining - the ceramic is harder than any metal tool - holds tolerances under 10 microns, and diamond-paste polishing takes the surface to Ra under 0.01 microns

That mirror finish is not cosmetic: a smooth surface minimises wear and gives a crack nowhere to start.

Defects and their control. Pores are stress concentrators, and they come in two kinds: closed pores are isolated voids within grains or at grain boundaries, and open pores are connected pathways that admit fluid and weaken the structure. Hot isostatic pressing takes final porosity below 0.1% by volume, and X-ray computed tomography detects any internal pore above 5 microns. The other failure of manufacture is abnormal grain growth, where a few grains reach ten to twenty times the normal size; chromium oxide pinning the grain boundaries is the control, and the specification is that 95% of grains lie within twice the mean.

Proof testing. Every component is deliberately stressed before it can be implanted, on the principle that a pre-existing flaw will declare itself by failing the test rather than failing in a patient. Burst pressure testing takes the component to 150% of anticipated in vivo stress and load-to-failure testing to three to five times peak physiological load, and over 99.5% of components pass.

Three materials are used in arthroplasty, and they follow one another as attempts on the same problem. Alumina (Al2O3) is hard but brittle. Yttria-stabilised zirconia (Y-TZP) is tougher but unstable in the body. The alumina matrix composite puts a little of the second inside the first.

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Why zirconia aged. Body fluid drives the transformation: moisture-assisted hydrothermal degradation converts metastable tetragonal zirconia to the stable monoclinic phase over time, and the volume expansion lifts the surface into a roughened relief. A rough head abrades polyethylene, and measured wear rose to 0.1-0.3 mm/year. The transformation is detectable at two to five years and the roughening becomes significant at five to ten.

Why the composite does not. Zirconia is only 17% of the volume, against 100% in a pure zirconia head, and the alumina matrix physically constrains the platelets so they cannot expand in bulk; BIOLOX Delta has shown no phase transformation after more than twenty years of clinical use. Zirconia, in other words, is not a failed material - it is a failed bulk bearing that works as a dispersed reinforcement.

What is available now. First-generation alumina is historical, and second-generation alumina, although still approved, has largely been superseded. BIOLOX Delta received FDA approval in 2003, is TGA approved and widely used internationally, and accounts for over 90% of ceramic bearings, with an AOANJRR revision rate of 4-5% at ten years in use, with extensive post-market surveillance behind it.

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The case for ceramic-on-polyethylene. A ceramic head on crosslinked polyethylene wears less than a metal head does, because the ceramic surface resists the scratching that turns a metal head into an abrasive. Only the head can fracture, so liner fracture leaves the risk list altogether and squeaking becomes rare. The price is a wear rate several times that of ceramic-on-ceramic, and for many patients that is a price worth paying.

Who gets a ceramic-on-ceramic bearing. The argument is strongest in a young, active patient whose projected lifespan exceeds thirty years, where minimising lifetime wear and osteolysis is the whole point, and where normal anatomy and good bone quality allow the cup to be put where it should be. Metal sensitivity and revision for osteolysis are the other two clear indications, the second because the aim is to stop generating particles.

Who should not. Anything that raises fracture risk or makes the cup hard to position argues for polyethylene instead.

• BMI over 35 - higher joint reaction forces
• Very high-impact sport, where peak loads raise fracture risk
• Severe dysplasia, or revision bone loss, that forces a steep or medialised socket
• Anatomy that predisposes to impingement: coxa vara, a retroverted femur, a short femoral neck
• A high fall risk, or cognitive impairment that will prevent the patient reporting noise or pain
• The patient who does not want to accept a squeaking risk at all

Cost belongs in the conversation. Ceramic costs more than crosslinked polyethylene, and above 75 years, with a projected implant lifespan of ten to fifteen years, the wear advantage is largely irrelevant.

Age as a rough guide. Under 50-60 with high activity, ceramic-on-ceramic is the first choice, on a projected implant lifespan of 30-40 years, with ceramic-on-polyethylene the alternative if the patient declines the squeaking risk. Between 60 and 75 either is defensible and the decision is genuinely shared. Over 75 the bearing does not need to be ceramic at all.

What to say in clinic. The offer is the lowest wear rate available, no osteolysis because the particles are too small to provoke it, registry survivorship out beyond twenty years, and resistance to third-body scratching from cement or metal debris. In a young patient the point of all that is to minimise the lifetime revision burden, and possibly to avoid revision altogether.

The cost side is squeaking, a rare but catastrophic fracture, a more complex revision if that fracture happens, and a higher implant price the patient may bear themselves in private practice. Add the honest admission: crosslinked polyethylene also performs excellently, so whether ceramic adds anything beyond twenty to thirty years is not yet known.

Run the conversation in that order: lay out the three realistic couples, ask what the patient is optimising for - longevity, cost, or certainty about noise - give a recommendation based on their age, activity and anatomy, and let them make the final choice.

How ceramics wear. What little wear occurs in a ceramic-on-ceramic bearing is mostly adhesive, and even that is minimal because the hardness prevents material transfer. The bearing does not fatigue under cyclic load and resists abrasion by third-body particles of cement or metal, which is why a ceramic head keeps its finish where a metal head would be scratched.

Microseparation. The head separates transiently from the centre of the cup during the swing phase of gait and relocates with rim (edge) contact at heel-strike. It is the dynamic mechanism underlying stripe wear and much ceramic squeaking, and it explains why these occur even with cups that are only mildly malpositioned. The factors that let the head lag behind the cup are:

• Cup malposition - steep inclination, or excessive or insufficient anteversion, brings the rim into the contact path
• Reduced femoral offset or soft-tissue laxity - abductor slack lets the head drift laterally in swing
• Impingement levering the head out of the cup
• Head-cup clearance and design - larger clearance permits more separation

What it does. At relocation the head strikes the liner rim rather than the dome, a small high-stress contact that produces a visible stripe wear band and roughens the surface. The roughening disrupts fluid-film lubrication, which generates squeaking and locally raises the wear rate from under 0.005 to around 0.01-0.02 mm/year within the stripe. Severe, repetitive edge loading is also the dominant mechanism of liner fracture.

Stripe wear itself is a gradual process, not a catastrophe: it is visible as a stripe on the head or at the liner equator, may remain asymptomatic for years, and is prevented rather than treated - by accurate cup position (40° inclination, 15° anteversion, avoiding inclination over 50°), by restored offset, by a larger head (36mm rather than 28mm), and by avoiding impingement.

Why the testing matters. Standard hip-wear simulators that keep the head concentric in the cup grossly underestimate ceramic wear. Only simulators that deliberately incorporate a microseparation protocol reproduce the clinical stripe-wear pattern and realistic wear rates, which is why pre-clinical ISO wear testing of hard bearings now includes microseparation. Generic adhesive, abrasive and fatigue wear modes are developed in the wear-mechanisms and tribology-wear topics.

Why the particles do not cause osteolysis. Ceramic wear particles are under 0.05 microns, too small for macrophage phagocytosis, and are cleared by the lymphatics without macrophage activation. Even when phagocytosed the cytokine response is minimal, and no osteolysis has been reported around a well-functioning ceramic bearing.

Assessing the acetabulum before you promise a ceramic bearing. An AP pelvis answers the question that decides the bearing: can the cup be put at 40° inclination and 15° anteversion with secure fixation? Measure the lateral centre-edge angle and acetabular index, and read severe dysplasia as a warning that the socket may have to sit steeply, which is exactly the position that edge-loads a ceramic liner. Bone stock has to be adequate to hold the cup in that position rather than wherever it will grip.

And the femur. Neck-shaft angle, offset and version determine whether the neck will meet the liner: coxa vara, a retroverted femur and a short femoral neck raise impingement risk. If the anatomy forces a steep cup or carries a high impingement risk, consider ceramic-on-polyethylene instead and accept the wear rate.

Patient assessment adds three things to that anatomical judgement: activity level, which sets how much the wear advantage is worth; BMI over 35, which raises joint reaction forces and fracture risk; and expectations, meaning a documented discussion of squeaking tolerance against longevity priority.

Intraoperative inspection is an investigation, and the last one that can prevent a fracture. Three checks, in order, before any ceramic component goes anywhere near the patient.

• The component - cracks, edge chips, discolouration that suggests a manufacturing defect, any scratch, pit or rough area. Reject it if anything is visible
• The packaging - expiry date checked and seal intact, because a compromised package guarantees neither sterility nor quality
• The paperwork - lot numbers of head and liner recorded and entered in the registry, so that a recall can be traced to the patient

Reading the postoperative film. Stripe wear appears on the lateral as a linear radiolucency at the equator of the liner, the zone of concentrated contact from a steep cup, and the culprit is usually inclination over 50-55° or excessive anteversion or retroversion. It indicates suboptimal position rather than impending failure and rarely requires revision unless wear is severe or the hip is symptomatic.

The signs of fracture are radio-dense ceramic fragments as small white particles in the joint space and surrounding soft tissues, a gap between head and neck taper or a liner separated from its shell, and - if the ceramic has gone completely - a metallic debris cloud from the head taper grinding against the metal shell.

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Working up the noisy or painful ceramic hip. Characterise the noise first, because the history does most of the work. Ask when it happens - stairs, standing from a chair, getting out of a car - whether it is constant or intermittent, whether others can hear it, whether it is embarrassing or limiting, and above all whether it hurts. Noise alone behaves very differently from noise with pain.

Then examine. Try to reproduce the noise in the impingement position of flexion, adduction and internal rotation, and assess range of motion for impingement, particularly flexion under 90° or painful terminal flexion.

Then the films. On an AP pelvis and lateral hip, four things are being looked for:

• Cup position - inclination (normal 30-50°) and anteversion (normal 5-25°)
• Stripe wear - at the liner equator
• Impingement - proximity of the femoral neck to the liner, anteriorly and posteriorly
• Loosening - radiolucent lines and migration, a rare cause of noise

If the films are inconclusive, CT measures version far more accurately than radiographic anteversion and allows three-dimensional impingement analysis.

Add blood tests when there is pain. Serum cobalt and chromium address trunnionosis, which produces metal debris from the taper despite a ceramic bearing, and ESR and CRP with aspiration address infection. Neither is needed for painless noise in a hip with a well-positioned cup.

What retrievals have taught us. Components recovered at revision are the only direct measurement of what happened in the patient, and four techniques answer different questions.

A ceramic bearing generates two management problems after the bearing has been chosen: a hip that makes a noise, which almost never needs an operation, and a hip whose bearing has broken, which always does.

The squeaking hip. Observe, with confidence, when the noise comes alone: no pain, full range of motion, a cup inside the safe zone and no progressive stripe wear on serial films. Reassure the patient that revision for squeaking alone is needed in under 0.1% of cases, suggest avoiding the provocative movement where that is practical, and repeat radiographs at six to twelve months to confirm the wear is not progressing. Many hips settle as the surfaces conform.

Surgery for noise is reserved for severe functional impact, progressive pain, or cup malposition with stripe wear that is measurably advancing; severe psychological impact belongs on that list too, as a patient-driven decision. An incidental asymptomatic stripe on a film is managed the same way - annual radiographs, a warning that squeaking may follow, and advice to avoid high-impact activity, which may accelerate wear.

The fractured bearing. The typical presentation is a patient with a ceramic-on-ceramic hip who falls, or simply twists, and has sudden severe groin pain with grinding and an inability to weight-bear. Radiographs may show frank fragmentation, or may look deceptively normal when only a liner has cracked, so compare with prior films and obtain a CT if the film is unconvincing and the history is typical.

Image it before you plan it. CT with metal-artefact reduction is the study when the fragment distribution or the extent of osteolysis is unclear, and MARS MRI adds the soft-tissue picture, including synovitis.

Revision is urgent rather than emergent unless the pain or instability is severe: within two to four weeks, with the patient consented for a complete synovectomy, for exchange or retention of components as found, and for the fact that not every fragment can be recovered.

Retained ceramic is the whole problem. Ceramic is harder than any bearing material you can implant against it, so fragments left behind act as third-body abrasive and destroy the revision bearing. Every decision below follows from that.

Why polyethylene is the second choice, not the first. Residual ceramic accelerates polyethylene wear - reported at ten to a hundred times normal - and fragments embed in capsule, muscle, the shell and the trunnion, where no debridement will reach all of them. A ceramic liner is therefore used wherever the shell accepts one, and highly crosslinked polyethylene is the fallback when it does not.

The other two constructs. Where instability rather than the bearing alone is the problem, a constrained liner is the alternative. Metal-on-metal appears in older accounts of this revision as a historical option, and is avoided now for its metal-ion concerns.

Irrigation at revision for an established fracture is 12-15 litres of normal saline by pulsed lavage, changing tips frequently so that particles are not reintroduced.

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Re-heading a retained stem. When a well-fixed femoral stem is retained at any revision involving a ceramic head, a new ceramic head must never be impacted directly onto the used femoral taper. The original head burnishes and microscopically deforms the taper, so a fresh ceramic bore no longer mates congruently with the altered surface; the resulting point contact and uneven seating create radial tensile stress in the bore and risk early head fracture. Any retained ceramic debris on the taper is a further stress riser.

The solution is a dedicated titanium adaptor sleeve (for example BIOLOX OPTION) placed over the used taper, so that the new ceramic head seats onto a pristine sleeve rather than a damaged cone. It is the manufacturer-mandated way to put a ceramic head on a retained stem. If the taper is grossly damaged or corroded, or the stem is loose, revise the stem instead. Generic mechanically-assisted taper corrosion is developed in the trunnionosis-taper-corrosion topic; this is specifically the ceramic-head re-heading rule.

Counsel the patient honestly: this revision does not perform like a primary. The landmark multicentre survivorship series of revisions after fracture of an alumina ceramic head reported roughly 63% survival at five years — far below a primary hip — and identified the recurring reasons for failure: the cup was not exchanged, a stainless-steel head was used, total synovectomy was omitted, or the patient was under 50. Contemporary revisions using fourth-generation ceramic bearings do considerably better, with midterm registry survival around 90% at seven years, but the operation still carries the higher infection risk of a long procedure with extensive synovectomy, and audible squeaking may follow a ceramic-on-ceramic revision.

Preparing and seating the cup. Ream sequentially to size, typically under-reaming by 1-2mm for a press-fit shell, keeping the medial wall intact because excessive medialisation costs cup stability, and aiming the reamer at 40-45° of inclination so the final position follows. Trial the cup, check inclination and anteversion against an alignment guide, and correct anything approaching 50° of inclination before the shell goes in.

Impact the shell line-to-line or with a 1-2mm press-fit, with the impactor aligned to the intended position vector, using controlled sequential blows - excessive force here fractures the acetabulum rather than the ceramic. The shell should end flush with the prepared bone with no gaps. If bone quality is poor or this is a revision, one or two screws in the posterosuperior quadrant supplement fixation, placed in the posterior column away from the sciatic notch, or in the ilium above the dome.

The liner. Inspect it, then keep it dry and clean: blood, saline or cement on the taper prevents it seating fully. The ceramic liner has a metal backing whose Morse taper locks into the shell, and many designs have anti-rotation features, so check the orientation marks before anything is impacted.

• Press it in by hand first; it should seat partially
• Impact with the manufacturer's plastic or soft-metal impactor, controlled gentle blows - three to five taps, with a change in pitch as it seats
• Never a metal instrument directly on a ceramic surface
• Verify by eye that it is flush with the shell, run a finger round the rim for a smooth transition, and try gently to displace it; it should be rock-solid

A polyethylene liner is more forgiving throughout, which is what makes each of those rules a ceramic rule. It withstands more forceful impaction, accepts a standard metal impactor, is less sensitive to taper cleanliness, tolerates a suboptimal cup position better, and may be used with minor scratches.

The stem. Broach sequentially to size and insert the stem by standard cemented or cementless technique, aiming for 10-15° of anteversion, which with the cup gives a combined anteversion of 25-50°, and confirming version on the trial. Axial and rotational stability are what the rest of the construct depends on.

Trial before any ceramic goes on. Use a trial metal head on the real stem and a trial liner in the real cup, and assess stability, range of motion, the impingement-free arc, leg length and offset. Confirm the cup sits under 50° of inclination with appropriate anteversion. Anything unsatisfactory is corrected now - once the ceramic head is on the taper, the options narrow.

The ceramic head. Inspect it, and keep both the head bore and the femoral taper completely dry. Wipe the taper with a dry sponge, not saline, and remove any metal debris, cement or bone fragment that would hold the head off its seat.

Align the head, then impact with the manufacturer's plastic impactor - never a metal mallet on ceramic - using two to four gentle taps with force increasing gradually; a seated head rings at a higher pitch than the dull thud of an unseated one. If it has not seated after four or five taps, remove it and look for debris or damage.

Then prove it is on. Pull gently: it should not budge. Try to rotate it on the taper: it should not move. The gap between the base of the head and the neck shoulder should be minimal, typically under 1mm.

Head size. A larger head gives a better head-to-neck ratio, a greater range of motion and more jump distance, so it dislocates less; registry data also show fewer fractures with larger heads. The constraints run the other way: the cup has to be large enough for the liner wall thickness, so a 36mm head needs a shell of 52mm or more and a 40mm head one of 56mm or more, and the larger head brings more torque at the taper and more squeaking. 36mm is the usual compromise, and the head diameter must match the liner internal diameter exactly.

Reduction and closure. Reduce gently, supporting the head and guiding it into the liner rather than letting it clunk in, then take the hip through a full range to confirm a smooth reduction and test stability in flexion-adduction-internal rotation and extension-adduction-external rotation. During closure keep the hip near neutral, avoid extreme positions that risk dislocating the new bearing, and place any drain away from the joint.

Getting the cup where you said you would. A rod or laser guide on the impactor shows the orientation; the transverse acetabular ligament approximates anatomic version but not true version; and intraoperative fluoroscopy of the AP pelvis measures inclination directly. Avoid inclination over 50°, which edge-loads, and anteversion over 25°, which brings posterior impingement.

Navigation and robotics narrow the spread: cup position within ±2-3° against ±5-10° freehand, with real-time adjustment before final impaction, and outliers outside the safe zone falling from 20-30% to 5-10%. The costs are money, operative time, a learning curve, and registration errors that propagate straight into cup position. Reserve them for complex cases - dysplasia, revision - or for the surgeon early in the learning curve.

Pelvic tilt moves the target. Supine films show the anatomic position; standing films show the functional one, and in posterior pelvic tilt the functional cup is more vertical than the anatomic measurement suggests. Where sagittal alignment is abnormal, adjust the anatomic target: with a PI-LL over 10° (flat back, posterior tilt) aim for 35-38° anatomic inclination, which becomes 40-45° functional; with a PI-LL under -10° (hyperlordotic, anterior tilt) aim for 42-45° anatomic, which becomes 38-42° functional.

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What is different about a ceramic hip. Four problems belong to the bearing: fracture of head or liner, squeaking, stripe wear, and trunnionosis where large heads are used. The general complications of hip replacement are all still possible, but their profile shifts - dislocation is similar or lower because larger heads are available, infection is unchanged, and osteolysis and late aseptic loosening are lower because there is almost no particulate debris to drive them.

The differential of the symptomatic ceramic hip is a standard exam scenario, and it is worked through the same way every time: is this noise or pain, is it acute or insidious, and does the film or the blood test explain it?

Head and liner do not fracture for the same reasons, and that distinction drives both prevention and consent. A head fractures because of what happened at the taper; a liner fractures because of where the cup was put.

The sequence in a liner is worth rehearsing, because every step of it is a chance to intervene.

1. A cup left over 50° of inclination loads the head onto the liner rim rather than the dome during stance
2. The concentrated rim stress exceeds the fracture threshold of the ceramic
3. A crack starts at the rim and propagates into the body of the liner
4. The liner fails catastrophically, fragmenting into the joint

Component mismatch, impingement and trauma amplify it. Fracture can occur from days to years after implantation, typically within the first two years, and modern Delta components tolerate more edge-loading stress before they fail but fail just as catastrophically when they do.

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Squeaking. Reported in 1-8% of ceramic-on-ceramic hips, with the range that wide because studies and implant designs differ, it is a high-pitched noise heard on specific movements - standing from a chair, climbing stairs - and arises when the fluid film between the surfaces is disrupted by edge loading and microseparation. Over 90% are self-limiting and under 0.1% are revised for noise alone; pain or functional loss is what turns a squeak into an investigation.

The risk factors depend on which literature you read, and a candidate should say so. Single-centre series implicate a steep cup over 50°, shorter patients, large heads of 40mm and above, and particular implant designs. The pooled meta-analysis found the reproducible associations to be rising BMI and one specific beta-titanium stem, and did not confirm cup position or a raised metallic lip.

The honest summary is that squeaking is multifactorial, that implant design and patient factors are the reproducible associations while the link with cup malposition is less consistent in pooled data than single-centre series suggest, and that optimal cup position remains worth achieving for every other reason.

Head size, dislocation and the taper. Dislocation falls as the head grows - from 3-4% at 28mm to 1-2% at 36mm and under 1% at 40mm - while squeaking rises and so does torque at the head-taper junction. That torque is the mechanism of trunnionosis: mechanically-assisted crevice corrosion at the trunnion, accelerated by large heads, long neck lengths and their longer moment arm, a Ti-6Al-4V taper (more susceptible than cobalt-chrome), and high activity.

Trunnionosis presents as groin or thigh pain with raised serum cobalt and chromium from the taper rather than the bearing, occasionally a pseudotumour, and visible taper wear at revision. Prevention is to use 36mm rather than 40mm where the choice is free, to keep neck lengths short or neutral where biomechanics allow, and to use the titanium sleeve adaptors available in some designs.

The first two days are the same as any hip replacement. Mobilise on day 0 or day 1, weight-bear as tolerated, give thromboprophylaxis per protocol, inspect the wound at 24 hours and use multimodal analgesia. Nothing about a ceramic bearing changes immediate care, including weight-bearing, which follows the fixation rather than the bearing.

Through the first six weeks the work is progressive mobilisation with aids, hip precautions for the approach used, wound care with sutures or staples out at 10-14 days, and physiotherapy for range and strength. The one ceramic-specific item is a conversation about noise: tell the patient it may happen, that it is usually benign and self-limiting, and what would make it worth reporting.

Ceramic does allow the larger heads, 36mm and 40mm, that reduce dislocation risk and may permit relaxed precautions, but that remains a matter of surgeon preference and approach rather than a property of the bearing.

Enhanced recovery applies unchanged, and the ceramic-specific element sits in theatre, not in the pathway: preoperative education that includes the squeaking discussion, optimisation of diabetes, anaemia and nutrition, smoking cessation six or more weeks before surgery, carbohydrate loading up to two hours preoperatively and minimal fasting (six hours for solids, two for clear fluids).

• Anaesthesia and surgery - spinal preferred for less blood loss, nausea and respiratory complication; multimodal analgesia with local infiltration or periarticular injection; tranexamic acid; normothermia; goal-directed fluid therapy
• Day 0 - oral intake at two to four hours, mobilisation the same day, early removal of any urinary catheter, oral multimodal analgesia to minimise opioids
• Day 1-2 - progressive mobilisation including stairs, discharge on functional criteria, same-day discharge for selected patients
• Target length of stay - 1-3 days, against a historical 5-7

Aspirin 100mg twice daily is increasingly accepted for standard-risk patients, with equivalent prevention and a lower bleeding risk.

Activity and the bearing. How much the bearing minds depends on the load, not the wear.

• Low impact (walking, swimming, golf) - minimal wear, excellent longevity, no restriction
• Moderate impact (hiking, cycling, doubles tennis) - low wear, generally permitted on patient preference
• High impact (running, singles tennis, skiing) - potential for edge loading and squeaking, so a discussion rather than a rule
• Very high impact (contact sports, jumping) - higher fracture and dislocation risk, generally discouraged

The point to make to the patient is that ultra-low wear means activity level matters less to a ceramic bearing than to polyethylene. The concerns that remain are mechanical - dislocation and fracture - not wear.

Driving resumes when the patient is off opioid analgesia, has a brake reaction time under 700ms, and can drive without violating hip precautions.

Surveillance. A baseline immediately after surgery, then films timed to the complications that occur at each stage.

Survivorship at ten years does not separate the bearings. Registry and published series put ceramic-on-ceramic at 95-97% and metal-on-crosslinked-polyethylene at 95-96%, a difference of no significance, and the honest conclusion is that bearing choice is not what determines whether a hip is revised in its first decade.

Beyond fifteen years the data thin out. Ceramic-on-ceramic survivorship of 90-94% at 15-20 years is reported, and the theoretical argument - that lower wear should mean less late osteolysis - remains theoretical because BIOLOX Delta has only been available since 2003-2005 and the registry curves are still being drawn.

Patient-reported outcomes are equivalent between bearing surfaces at short-to-medium-term follow-up.

Where ceramic does separate is wear, and therefore osteolysis. The ten-fold lower wear rate translates into a negligible osteolysis risk - an advantage that only matters if the patient lives long enough to need it.

Registry Evidence: Joint Replacement Registries

National joint replacement registries (AOANJRR, NJR, Swedish Arthroplasty Register and others) are the primary real-world evidence source for bearing-surface performance. National registries mandate lot-number traceability for implant recall and surveillance. The pooled, PubMed-indexed synthesis of these registries (Pentland 2026, DOI) reports an all-cause THA survivorship of 93.6% (95% CI 92.3-94.7) at 20 years across eight national registries, with modern bearings including third- and fourth-generation ceramics. Registry-level themes consistent across reports and the peer-reviewed literature:

• Equivalent broad survivorship: Ceramic-on-ceramic and ceramic/metal-on-highly-crosslinked-polyethylene show broadly comparable mid-term all-cause revision; bearing choice is not the dominant driver of revision in registry data.
• Mode of failure differs: Ceramic-on-ceramic essentially eliminates wear-driven osteolysis but adds the bearing-specific risks of ceramic fracture and squeaking; polyethylene bearings carry wear/osteolysis risk that scales with time and activity.
• Younger patients: Registries record higher ceramic-on-ceramic and ceramic-on-XLPE use in younger, higher-demand patients, where minimising lifetime wear and osteolysis is prioritised.

The peer-reviewed cohorts of alumina matrix composite bearings that sit behind those registry figures are worth knowing individually.

Modern fourth-generation Delta ceramic series consistently report no osteolysis and very low fracture rates, with the major real-world signal being patient-reported squeaking (Hamilton 2015, DOI; Kim 2016, DOI; Darwish 2024, DOI; Pentland 2026, DOI).

Trend: Delta ceramic shows excellent osteolysis-free midterm-to-long-term survivorship; head fracture is now rarer than with alumina (Massin 2014), while liner fracture under edge loading remains the dominant hard-on-hard failure mode.

Cost. A ceramic bearing costs more up front and is cost-effective only where it prevents an operation.

That arithmetic works in patients with a life expectancy over twenty years, where the lower revision rate offsets the implant price, and not in patients without one.

Ceramic-on-polyethylene combines the low wear of a ceramic articulation with the toughness of polyethylene, removes liner fracture and makes squeaking rare, and is an increasingly popular alternative for exactly those reasons.

Global Epidemiology and Practice Variation

Total hip arthroplasty is performed in well over a million patients annually worldwide, and bearing-surface choice varies markedly by country and patient age. The largest contemporary synthesis of bearing performance pooled 1,904,237 THAs from 29 studies and eight national registries and reported 93.6% all-cause survivorship at 20 years for modern bearings, including third- and fourth-generation ceramics, with an extrapolated 92% at 30 years (Pentland 2026, DOI). Fourth-generation zirconia-toughened alumina (BIOLOX Delta, CeramTec) is the dominant ceramic worldwide.

Practice variation:

• Ceramic-on-ceramic use is comparatively high in parts of continental Europe and East Asia (notably South Korea and Japan), where young, high-demand cohorts are common.
• Ceramic-on-highly-crosslinked-polyethylene is increasingly the default "low-wear" couple in high-income settings including Australia, the UK and North America, balancing low wear against elimination of liner fracture and squeaking.
• Metal-on-highly-crosslinked-polyethylene remains the global volume leader, especially in older patients.

Side-by-Side Guidance and Standards