Cemented or Cementless—and When Does Porous Titanium Matter?

What Is the Practical Difference?

Cemented and cementless fixation solve the same fundamental problem in different ways: creating a stable implant-bone construct.

Cemented fixation relies on a prepared bone-cement-implant interface to establish fixation at surgery.

Cementless fixation depends on adequate initial mechanical stability, followed by biological fixation through bone ongrowth or ingrowth.

Porous titanium belongs within the second strategy. It is a material-and-structure technology—not a fixation method and not a clinical outcome by itself.

The practical question is therefore not:

Which fixation method is more advanced?

It is:

Which fixation strategy can create a reliable construct in the available bone, for this anatomy and this reconstruction goal?

Neither cement nor porous titanium can compensate for a reconstruction whose mechanical foundation is inadequate.

Start With Bone, Not With Age or the Implant Catalogue

Age can influence fixation decisions, but age alone is a poor substitute for understanding the bone and anatomy in front of the surgeon.

Before selecting a fixation strategy, the more useful questions are:

What is the quality and distribution of the available host bone?
Can reliable mechanical fixation be achieved in the intended region?
Has deformity, dysplasia or previous surgery changed the anatomy?
Is this a routine primary reconstruction or a revision with bone loss?
What fixation and biomechanical goals must the implant achieve?

This is why the shortcut—

younger = cementless, older = cemented

—is too simple.

A younger patient with unfavorable anatomy does not automatically become an ideal cementless candidate. An older patient with suitable bone does not automatically have only one reasonable fixation option.

Chronological age should inform the decision, not replace the anatomical assessment.

Cemented Fixation: The Interface Is the Construct

Cemented fixation is sometimes described as if the cement itself provides the answer.

In practice, fixation depends on the complete workflow:

bone preparation → cleaning and drying → cement delivery → pressurization → component positioning → controlled curing.

AK Medical’s CP Cemented Cup Surgical Technique provides a useful product-specific example.

For that system, the technique describes an intended cement thickness of approximately 2–3 mm. It also describes cup positioning at 45° of extroversion and 15° of anteversion during implantation.

Numeric Snapshot 1 — AK CP Cemented Cup

Product-specific parameter	Documented value
Intended cement thickness	~2–3 mm
Extroversion in Surgical Technique	45°
Anteversion in Surgical Technique	15°

These values belong to the AK CP Surgical Technique. They should not be interpreted as universal positioning or cement-mantle targets for every cemented acetabular system.

The broader lesson is more important:

Cemented fixation is only as reproducible as the interface and technique used to create it.

Cementless Fixation: Where Porous Titanium Actually Matters

Cementless implants need stability before biological fixation can develop.

That initial fixation comes from the interaction among implant geometry, preparation, press-fit or cortical engagement, host-bone contact and supplemental fixation where required.

Porous titanium becomes relevant when its architecture contributes to the next stage: biological fixation.

The word porous, however, is not enough.

For the 3D ACT acetabular cup described in published clinical studies, reported design parameters include a 1.5 mm porous layer, pore sizes of 600–800 μm in primary THA studies, and porosity of approximately 80%.

Numeric Snapshot 2 — Studied 3D ACT Acetabular Cup

Reported parameter	Published value
Porous layer thickness	1.5 mm
Pore size in primary THA studies	600–800 μm
Porosity	~80%

These values apply to the studied cup and should not be generalized to every 3D ACT product or every porous titanium implant. Current market-specific specifications should be confirmed from applicable product documentation.

The clinically relevant question is therefore:

Does this porous architecture contribute meaningfully to fixation in the reconstruction being considered?

Not:

Is porous titanium newer?

Primary and Revision Surgery May Require Different Fixation Philosophies

Primary THA and revision THA do not always offer the surgeon the same bone.

In primary reconstruction, suitable proximal or metaphyseal bone may allow several established fixation strategies.

Revision changes the problem.

Proximal bone may be compromised. The canal may be altered. Previous implants may have changed the available fixation zone. In some cases, fixation may need to move distally into more reliable host bone.

AK Medical’s AK-SL Revision Stem illustrates this type of product-specific philosophy.

The stem uses a 2° taper and 8 longitudinal ribs. It is available in 190 mm and 225 mm lengths, with 16 sizes and 1 mm diameter increments.

Numeric Snapshot 3 — AK-SL Revision Stem

Design characteristic	Documented value
Taper	2°
Longitudinal ribs	8
Stem lengths	190 / 225 mm
Size range	16 sizes, 1 mm diameter increments

These are AK-SL-specific design characteristics, not general rules for revision stems.

They illustrate the more important principle:

When the fixation environment changes, the implant philosophy may need to change with it.

A revision stem is not simply a larger primary stem.

What Should Surgeons and Hospitals Actually Compare?

The fixation label alone is not enough.

A meaningful evaluation should include:

fixation philosophy, implant geometry and the host bone required for that strategy;
Surgical Technique, instrumentation and the reproducibility of preparation;
surface or porous architecture when biological fixation is intended;
primary-to-revision options and compatibility across the broader reconstruction pathway;
product-specific clinical evidence, regulatory status, supply availability and technical support.

This matters commercially as well as clinically.

A hospital may be choosing between two technically reasonable systems, but the real operational difference may lie in instrumentation, inventory, revision options or access to product documentation.

For the surgeon, the question is:

Can this implant achieve the fixation required for this patient?

For procurement, the additional question is:

Can this system be implemented reliably in our hospital or network?

Where AK Medical Fits—and Where to Go Next

AK Medical’s current hip portfolio spans primary replacement, cemented fixation and revision reconstruction. Its official English product catalogue includes primary hip systems, cemented femoral options and revision products such as the AK-SL Femoral Stem, AK-ABM System, 3D ACT Augments and AK-Ringfix Cup. AK Medical

That allows fixation to be discussed as a reconstruction pathway rather than as a contest between two technologies.

For one case, the relevant question may be whether a cemented construct is the more reproducible solution.

For another, cementless biological fixation may be appropriate.

For a revision, the fixation target and implant geometry may need to change altogether.

The product should follow that logic.

Explore AK Medical Hip Products

For a specific primary or revision hip case, product enquiry, regulatory information or technical discussion:

Discuss a Hip Reconstruction Case with the AK Medical International Team

AK Medical’s current official contact page lists sales@ak-medical.net and WhatsApp +86 150 0110 2275 for international enquiries.

Frequently Asked Questions

Is cementless fixation always preferable in younger patients?

No. Age is one factor, but bone quality, anatomy, activity, fixation potential, implant design and reconstruction goals also matter.

Can cemented fixation still be appropriate in modern hip arthroplasty?

Yes. Cemented fixation remains an established strategy when an appropriate and reproducible bone-cement-implant construct can be achieved.

Is porous titanium a fixation method?

No. It is a material-and-structural technology used within a cementless fixation strategy.

Does higher porosity automatically mean better fixation?

No. Porosity is only one design variable. Initial stability, pore architecture, host-bone contact and the mechanical behavior of the complete implant also matter.

Does a porous implant still need good initial stability?

Yes. Biological fixation develops after implantation; it cannot substitute for inadequate mechanical stability at surgery.

Why can revision THA require a different stem philosophy?

Because bone loss and altered anatomy may change where reliable fixation can be obtained. Revision stems may therefore use different geometries, fixation zones or modular concepts.

What evidence should hospitals ask for?

Evidence should be product-specific whenever possible and should be interpreted according to the exact implant, indication, study population, follow-up and study limitations.

Professional Notice

This article is intended for professional education, clinical technology evaluation and hospital procurement discussion. It does not constitute patient-specific medical advice.

Product-specific dimensions, angles, fixation requirements and Surgical Technique parameters presented in this article apply only to the cited AK Medical products and should not be generalized to other devices.

Indications, contraindications, warnings, specifications, compatibility, regulatory status and product availability may vary by product and market.

Treatment and implant selection should be determined by appropriately qualified clinicians using the applicable Instructions for Use, Surgical Technique, patient-specific clinical information and local regulatory requirements.