Allergy to Metal Orthopedic Implants

Metal implants are used in a variety of orthopedic surgical settings, including fracture repair and joint replacement surgery. Some people are concerned about developing an allergic reaction to metal implants. Is this possible, and could it be a cause of pain or irritation after surgery?

Hypersensitivity or allergy can occur after contact with various metals. While the words "hypersensitivity" and "allergy" are often used interchangeably, they are not really the same. That said, in the discussion of metal implants in the body, these words are often used in the same discussion. 

Some people may be prone to developing a response to various metals, such as skin sensitivity to jewelry or watches. Whether a similar sensitivity may develop to metal implanted inside the body is not yet well understood, but there is some evidence it can happen.

Metals Implanted in the Body

The most common metals used in orthopedic implants are cobalt-chrome, stainless steel, and titanium. In general, orthopedic implants are alloys, meaning they have more than one type of metal in the implant. The base metal(s) are found in the highest quantities, but smaller amounts of other metals are also often found in orthopedic implant alloys, such as nickel, aluminum, or other metals.

Many people have known skin sensitivities to various metals. One frequently encountered metal sensitivity is to nickel. Some orthopedic implants contain small amounts of nickel, and there has been a concern that this may be an issue for individuals receiving implants who also experience skin irritation from this metal.

Should I Be Concerned About Metal Allergy When Getting an Implant?

Metal sensitivities and allergies have been implicated in some situations of painful or problematic orthopedic implants. While this can potentially be a cause of implant problems in some situations, it is thought to be extremely rare. Pain around the site of orthopedic implants has many causes, and before blame can be assigned to metal sensitivity or allergy, a thorough investigation must occur.

Unfortunately, the symptoms of metal implant sensitivity and allergy are not well defined. Having a skin sensitivity to a particular metal is not thought to correlate well to having sensitivities to implanted metals. Therefore, making the diagnosis of a sensitivity or allergy to metal implants usually requires the removal of the implant.

Skin Sensitivity to Nickel

As many as 10 to 15 percent of the general population has a sensitivity or allergy to nickel. Patients who are sensitive to nickel should inform their doctors of this reaction. Your doctor may want to consider the use of an implant made without a nickel in the alloy (usually a titanium implant). This may not always be possible, and an implant made with nickel may be the most appropriate implant available for your condition. Fortunately, the chance of developing problems with metal implants, even in people with known skin sensitivities, is extremely low.

Should I Have My Metal Implant Removed?

Removal of metal implants for the treatment of an allergy or sensitivity to metal is rarely performed. While it is nice to know that metal implants rarely cause allergic reactions that require implant removal, cases have been reported, and some individuals have found the resolution of their symptoms after removal or replacement of their implants. However, because this can involve another surgery that may not necessarily be simple, your doctor can help you determine the cause of your problems and the appropriate treatment to consider. Fortunately, for those patients who indeed have metal sensitivity causing their implant problems, removal of the implant will often provide immediate relief of symptoms.

There are implants made of non-metal materials. Unfortunately, there is very limited data about the effectiveness and longevity of these non-metal implants. Some of these alternative implants are made of ceramics. How well these implants will last is not well known. Therefore, these materials are generally used in the specific circumstance where metal needs to be removed, or if there is a high likelihood of a particular individual having problems with a metal implant.