Metal Allergy and Joint Replacement

The short answer

A metal allergy is not a reason you cannot have a joint replaced. If nickel is what concerns you, there is a titanium implant that does not contain it, and using it is straightforward.

Plenty of people arrive at this question after being told their concern is unfounded, or after reading something that frightened them. Neither is a useful place to be left. What follows is what the metals actually are, what I do when a patient raises this, and what happens next.

If you are having a hip, this is barely your problem

The metal allergy question comes up constantly for knees and rarely applies to hips, because of what a modern hip is made of:

Nickel is not meaningfully part of that construct. If you have been putting off a hip replacement because you are worried about a metal allergy, that is very unlikely to be the obstacle you think it is. More on what these components are made of and why in hip replacement bearing surfaces.

Where the nickel actually is

In a knee replacement there are three pieces:

So the entire question comes down to one component out of three. The tibial side is already free of the metal people are concerned about, and the bearing surface is plastic. That narrows the problem considerably, and it is why the fix is as simple as it is.

What I see in practice

I want to give you an honest picture rather than either reassurance or alarm.

Implant failure caused by genuine metal hypersensitivity is something I have essentially never seen. When a knee is doing badly and allergy is raised as the explanation, the workup usually turns up a different cause — and the one that matters most is a low-grade infection that has not been diagnosed.

The titanium option

Here is the part that matters if you came to this page worried: I am not going to ask you to be convinced by me.

If you tell me you react to costume jewelry, or that you simply do not want nickel in your knee, that is enough. I will plan a titanium femoral component — a titanium-nitride-coated piece that replaces the cobalt-chrome one — and we will get on with fixing your knee.

Titanium is about as inert as implant materials get. True reactions to it are reported on the order of one in ten million, which is to say that in practice we do not see them.

Does the titanium version compromise the knee?

This is the question patients ask next, and it is a fair one — nobody wants to be given the special version and quietly receive a worse operation.

It is the same implant design in a different material. The medial pivot design I use for essentially all of my primary knee replacements is available with the titanium femoral component, with no exceptions. You are not trading away the design in order to avoid the nickel.

Your knee is templated, sized, rotated and balanced exactly the same way. The only difference is what the femoral piece is made of.

Allergy testing — what it can and cannot tell you

Patients often expect that a test should settle this. It is worth understanding why it usually does not.

I do not routinely send patients for it. If you feel strongly about having it done, we can arrange it. But if the concern is nickel, using the titanium component answers that concern directly, and it does so without a test, a bill, or a wait.

If you were told you cannot have surgery

I have had patients arrive in my office believing a metal allergy ruled out a joint replacement entirely. It does not.

If that is where you have landed — whether from something you read or something you were told — it is worth having the conversation again with the actual options in front of you. A second opinion is a reasonable thing to seek before you accept that you have to live with an arthritic joint.

Bring your X-rays and tell us what you react to. In most cases the answer is a short one.