The Metal Allergy Myth: Why Polymer Implants Like OsteoFab® PEKK Are Becoming the First Choice

For decades, metal has been the backbone of orthopaedic reconstruction. Titanium, stainless steel and cobalt chrome systems shaped the modern era of fixation, with titanium often held up as the inert standard. Hypersensitivity was described as rare, corrosion as theoretical and revision attributed to biology or biomechanics rather than any reaction to the implant itself.

But clinical practice has shifted. So has patient expectation. And so has the available evidence.

Surgeons are now working with a patient population that is more complex, more informed and more biologically variable than the one orthopaedics was built around twenty years ago. Patients present with a wider range of inflammatory and allergic histories. Dermatology literature has expanded significantly. Joint arthroplasty has also given us a clearer picture of how metals behave over long periods inside the human body.

The result is simple: the blanket reassurance that metal is always safe no longer holds up to scrutiny.

This is not an argument against metal. It is an argument for being honest about biology and for recognising what materials such as OsteoFab® PEKK offer that metals cannot.

Metal Hypersensitivity Is Not as Rare as Commonly Claimed

Earlier datasets around metal allergy relied heavily on patch testing for dermatitis, which inevitably underreported real-world sensitisation. Modern data paints a different picture. Depending on the cohort, nickel sensitivity affects between 15 and 20 percent of adults. Cobalt sensitivity ranges from 6 to 8 percent. Chromium sensitivity sits between 1 and 3 percent.

These are not fringe numbers. They overlap directly with the typical orthopaedic population.

More importantly, hypersensitivity can develop after implantation. Low-level chronic ion exposure can activate T cell pathways even if a patient had no documented allergy before surgery. In arthroplasty literature, patients who previously tolerated jewellery have developed new metal sensitivity following chronic exposure from an implant. In extremities, surgeons frequently encounter unexplained persistent pain, delayed recovery or low-grade inflammatory findings that cannot be attributed to infection or mechanics alone.

None of this removes the value of metal implants. But it does mean hypersensitivity should not be dismissed as rare or irrelevant. The biology is real, the patient variability is real and the consequences matter.

Metals Are Not Biologically Silent

Titanium, cobalt chrome and stainless steel all interact with the human body in predictable ways. Sometimes the effects are clinically insignificant. Sometimes they are not.

There is ion release in all metal implants over time. Titanium’s oxide layer is stable but not indestructible. Micro-motion, wear and local chemical changes influence it. Cobalt and chromium ions are measurable systemically. Stainless steel brings nickel into the biological environment. Corrosion is well documented. Galvanic corrosion can occur whenever mixed-metal systems interact.

Even when these processes do not cause overt implant failure, they contribute to immune activation. That activation may present as persistent discomfort, delayed progress, swelling or soft-tissue sensitivity. Symptoms like these can easily be interpreted as mechanical issues even when the underlying driver is biological.

The point is not that metals are unsafe. The point is that metals are not neutral. When a high-performance polymer exists that sidesteps these issues entirely, the traditional hierarchy of implant materials becomes more difficult to justify.

Why High-Performance Polymers Are Gaining Ground

The current movement towards non-metal implants is not driven by trends. It is driven by clinical reality. High-performance polymers solve problems that metals cannot.

OsteoFab® PEKK offers several advantages that have been validated across craniofacial, spine and extremity reconstruction. These advantages show up consistently in surgical workflow, imaging, biomechanics and patient follow-up.

• No ion release

• No corrosion

• Radiolucent imaging with minimal artefact

• Bone-like modulus that reduces stress shielding

• Strong and biologically aligned mechanical behaviour

• Compatibility with anatomical customisation

• No nickel, cobalt or chromium exposure

Each advantage is meaningful on its own. Combined, they define a fundamentally different class of implant that aligns with modern expectations for personalised, biologically aware surgical care.

Radiolucency Is a Practical Clinical Advantage

The ability to see the bone rather than the implant is one of the most valuable aspects of PEKK. Metal obscures accuracy. Titanium plates and screws dominate X-rays and create artefact in CT imaging. This complicates follow-up, particularly when assessing healing, alignment or adjacent joint behaviour.

PEKK’s radiolucency provides the opposite effect. It gives surgeons a clear view of the biological environment. Union can be assessed without obstruction. Subtle changes are visible earlier. Planning becomes more precise. Long-term review becomes more straightforward whether for trauma, reconstruction or oncology.

For younger and active patients, predictability over years and decades is especially relevant.

Mechanical Behaviour That Respects Bone Biology

One of the major challenges with metal implants is mismatch. Titanium is strong, but its modulus is far higher than cortical bone. That disparity contributes to stress shielding and non-physiological load distribution.

PEKK sits much closer to bone on the modulus spectrum. It supports load sharing in a way that mirrors natural biomechanics. It reduces the risk of stress risers. It avoids the micro-crack formation that can occur when metal plates are repeatedly bent and contoured in theatre.

When surgeons describe PEKK as bone-like, they are referring not only to its appearance but also to its mechanical behaviour.

A Material Patients Understand and Prefer

Modern patients bring a different set of expectations into consultation. They want clarity about what is being implanted. They want assurance that the material will behave predictably over time. They want alternatives to metal where appropriate.

Many patients with a history of jewellery sensitivity, dermatitis, eczema or autoimmune tendencies feel more comfortable avoiding metal entirely if proven alternatives exist. They respond well to materials described as stable, biologically quiet and designed to integrate with bone.

This shift in patient expectation has moved polymer implants from a niche category to an essential component of personalised care.

Evidence Already Exists Across Multiple Specialities

Poly-aryl-ether-ketone materials have been used for many years across several surgical disciplines.

Craniofacial surgeons adopted PEKK early because it avoids visibility issues, imaging artefacts and soft-tissue complications associated with titanium in delicate anatomical regions. In spine surgery, polymer cages and spacers have become common because radiolucency and modulus alignment support predictable outcomes. In orthopaedic oncology, modifiable radiolucent implants assist with reconstruction and long-term monitoring.

Extremity surgery is now reaching the same conclusion. Non-metal implants offer a clearer, more biologically aligned pathway for selected patients.

Why OsteoFab® PEKK Is Becoming the Logical First Choice

Surgeons choosing OsteoFab® PEKK consistently point to the same reasons. They are grounded in outcomes, workflow and long-term predictability rather than trend or novelty.

1. It eliminates the risk of metal hypersensitivity.

2. It avoids ion exposure.

3. It preserves imaging quality throughout the patient journey.

4. It aligns with bone biomechanics and reduces stress mismatch.

5. It supports anatomical customisation for improved precision.

6. It offers long-term stability without corrosion or galvanic interaction.

   
   

This reflects the broader direction of modern orthopaedics. The field is moving toward material-appropriate and patient-appropriate decision-making rather than defaulting to metal in every case.

Conclusion

The idea that metal hypersensitivity is rare or irrelevant is outdated. Patients today bring a wider range of immunological backgrounds, greater expectations for transparency and a stronger preference for biologically quiet materials that behave predictably over time.

OsteoFab® PEKK does not replace titanium in all scenarios. However, in many procedures it represents a more rational starting point. It avoids ion release, eliminates corrosion, preserves imaging accuracy, aligns with bone biomechanics and offers customisable design.

As orthopaedic care continues to move towards personalised, data-driven decision-making, the question is no longer why consider a polymer implant.

The more appropriate question is why start with metal when a better aligned alternative already exists.