Knee Metal Allergy and Sensitivity

Could You Be Allergic to Your Knee Implant?

The surprising answer to this question is yes.

While the majority of patients might not make the association between a knee implant and allergies, for anyone who has ever had an adverse reaction to things like jewelry, watches or metal buttons, the link is much clearer and more important. That's because your body's potential reaction to an orthopaedic implant may be predicted by your skin's reaction to items containing nickel or chromium - two metals present in stainless steel and in most metal knee implants. In many cases, sensitivity to these allergens has resulted in revisions for knee replacement patients.^1-3

Although tests show that less than 10% of the population has a current sensitivity to these metals⁵, it is possible to develop new allergies over the course of your lifetime. And while it is not clear what triggers new allergies, studies have shown that the rate of metal allergy increases to 25% in people who have a metal implant in their body and to 60% of patients who need to have their first implant surgically replaced.⁶

VERILAST^◊ Technology uses our proprietary OXINIUM^◊ Oxidized Zirconium for the femoral - or thighbone portion - component rather than the more commonly used cobalt chrome. Our OXINIUM alloy has less than 0.0035% nickel content, and less than 0.02% chromium content compared to up to 0.5% and 30.0% respectively in cobalt chrome.⁷ Moreover, oxidized zirconium is a nearly inert material that has not been reported to induce immune reactions.⁸

Important Safety Notes:

Knee replacement surgery is intended to relieve knee pain and improve knee functions. However, implants may not produce the same feel or function as your original knee. There are potential risks with knee replacement surgery such as loosening, fracture, dislocation, wear and infection that may result in the need for additional surgery. Longevity of implants depends on many factors, such as types of activities and weight. Do not perform high impact activities such as running and jumping unless your surgeon tells you the bone has healed and these activities are acceptable. Early device failure, breakage or loosening may occur if you do not follow your surgeon's limitations on activity level. Early failure can happen if you do not guard your knee joint from overloading due to activity level, failure to control body weight or accidents such as falls. Talk to your doctor to determine what treatment may be best for you.

1. Niki, Yasuo et al. "Screening for symptomatic metal sensitivity: a prospective study of 92 patients undergoing total knee arthroplasty." Biomaterials 26 (2005) 1019-1026
2. Nesser, s. "Biology of foreign bodies: tolerance, osteolysis, and allergy", Total Knee Arthroplasty, J. Bellemans, M.D. Ries, and J. Victor (eds.), Springer Verlag, Heidelberg, Germany, 2005, pp. 343-352
3. Granchi, Donatella et al. "Sensitivity to implant materials in patients with total knee arthroplasties." Biomaterials 29 (2008) 1494-1500
4. Hallab NJ, Anderson S, Stafford T, Glant T, Jacobs JJ. "Lymphocyte responses in patients with total hip arthroplasty." J Orthop Res 2005; 232:384e91.
5. Hallab, Nadim et al. Metal Sensitivity in Patients with Orthopaedic Implants, The Journal of Bone & Joint Surgery, Vol 83-A No. 3. March 2001 p428-436
6. Hallab, Nadim et al. Metal Sensitivity in Patients with Orthopaedic Implants, The Journal of Bone & Joint Surgery, Vol 83-A No. 3. March 2001 p428-436
7. ASTM International Standard Specification for Wrought Zirconium-2.5Niobium Alloy for Surgical Implant Applications (UNS R60901) Designation: F 2384 – 05 and Standard Specification for Cobalt-28 Chromium-6 Molybdenum Alloy Castings and Casting Alloy for Surgical Implants (UNS R30075): Designation: F 75 – 07
8. Zardiackas, Lyle D., Kraay, Matthew J., Freese, Howard L, editors. Titanium, Niobium, Zirconium, and Tantalum for Medical and Surgical Applications ASTM special technical publication; 1471. Ann Arbor, MI: ASTM, Dec. 2005