Pat Walter from Surface Hippies contacted me. I want to make it clear that I am not a qualified pathologist, nor a medical doctor, I am just a researcher with an interest in hip resurfacing and biomaterial compatibility. I run an independent implant retrieval research laboratory within the J. Vernon Luck Snr MD Orthopaedic Research Center at UCLA/Orthopaedic Hospital in Los Angeles. As such, I am the fortunate recipient of specimens and information from several orthopaedic surgeons, including Dr De Smet, who care enough about their patients to seek out knowledge to help solve patient problems, among which is metal sensitivity. I also want to emphasize that metal sensitivity to hip resurfacing replacements (or other hip replacements) is a problem that we (the orthopaedic community) are still learning about. (as well as the very much more common causes of problems with hip resurfacing such as fracture and loosening). Therefore, the material I include here should be considered preliminary and subject to change as more information is gained. That said, I hope your readers will find the attached description informative. Lastly, I would encourage the surface hippies to attend their regular follow up visits with their surgeons as the data obtained on the good as well as the problematical implants helps us all.Sincerely Pat Campbell PhD Assoc Prof. UCLA/Orthopaedic Hospital
Allergy to Joint Replacements
(from www.metalsensitivity.com – due online in 2008)
Occasional reports of joint replacement implant failure because of an apparent allergy to one of the metals in the device have appeared in the orthopaedic literature ever since metal implants were used. (1-3) It is now recognized that a small number of patients will suffer from a form of allergy or hypersensitivity to constituents of the metal-on-metal bearings even in the absence of high wear or a known metal sensitivity (4-6). The term ALVAL (aseptic lymphocytic vasculitis associated lesions) has been coined to describe the histological features associated with an allergy-like reaction in the joint tissues. (7, 8) It should be noted that some pathologists object to the inclusion of the “vasculitis” part of this new name and vasculitis in the strict sense of the word is not a prominent feature of the lesions.
Diagnosing metal sensitivity can be difficult, and it may be hard to differentiate it from a reaction to excessive wear or to infection if an organism is not cultured from the tissue or joint fluid. There is a wide variety of clinical presentations of metal sensitivity; typically the patients report ongoing pain or discomfort, typically in the groin, often accompanied over time with fluid buildup which may progress to form an enlarged fluid hernia or a groin mass. If a biopsy is taken, or the implant is removed, the characteristic tissue feature is an extensive lymphocytic infiltrate, which appear in the absence of infection or high component wear. It is important to note that lymphocytes can also be present in response to excessive wear debris and the reason for their presence is unclear (9,10).
If all possible causes for the patient’s pain can be eliminated by imaging or hematological testing, a diagnosis of metal sensitivity should be entertained and if confirmed, the cobalt chromium bearings should be removed to avoid ongoing soft tissue damage. (11) The number of revisions performed to remove cobalt chromium bearings because of a metal allergy is unknown, but it is thought to be a relatively rare complication.
Skin Sensitivity and Hip Sensitivity
Approximately 10–15% of the general population has a skin sensitivity to metal, nickel being the most common sensitizer, followed by cobalt and chromium. (5) There is concern, therefore, that patients with a skin sensitivity will also have an adverse reaction to a cobalt chromium hip replacement although there is little actual evidence to support this concern. It should be noted that the FDA lists skin sensitivity as a contraindication to metal-on-metal hip resurfacing. Skin patch testing has been unreliable as a way to test for allergies to hip replacements, and although lymphocyte transformation testing (a test done in a specialty lab on cells taken from the patient’s blood) is promising (12), it is premature to recommend this as a diagnostic test until more data are gathered to show it has predictive or diagnostic value. Research into better screening tests for metal sensitivity is ongoing.References
ADDIN ENBbu 1. Evans EM, Freeman MAR, Miller AJ, and Vernon-Roberts B: Metal sensitivity as a cause of bone necrosis and loosening of the prosthesis in total joint replacement. J Bone Joint Surg 56B:626-642, 1974. 2. Vernon-Roberts B, and Freeman MAR: Morphological and Analytical Studies of the Tissues Adjacent to Joint Prostheses: Investigations Into the Causes of Loosening of Prostheses. IN Schaldach M Hofmann D (eds). Advances in Hip and Knee Joint Technology, Springer-Verlag, New York, 1976, 148-186. 3. Deutman R, Mulder THJ, Brian R, and Nater JP: Metal sensitivity before and after total hip arthroplasty. J Bone Joint Surg 59A:862-865, 1977. 4. Gawkrodger DJ: Metal sensitivities and orthopaedic implants revisited: the potential for metal allergy with the new metal-on-metal joint prostheses. Br J Dermatol. 148:1089-1093., 2003. 5. Hallab N, Merritt K, and Jacobs JJ: Metal sensitivity in patients with orthopaedic implants. J Bone Joint Surg 83A:428-436., 2001. 6. Willert H, Buchorn G, Fayaayazi A, and Lohmann C: Histopathological changes around metal/metal joints indicate delayed type hypersensitivity. Preliminary results of 14 cases. Osteologie 9:2-16, 2000. 7. Davies AP, Willert HG, Campbell PA, Learmonth ID, and Case CP: An Unusual Lymphocytic Perivascular Infiltration in Tissues Around Contemporary Metal-on-Metal Joint Replacements. J Bone Joint Surg 87:18-27, 2005. 8. Willert H-G, Buchhorn GH, Dipl-Ing, Fayyazi A, Flury R, Windler M, Koster G, and Lohmann CH: Metal-on-metal bearings and hypersensitivity in patients with artificial hip joints. A clinical and histomorphological study. J Bone Joint Surg 87:28-36, 2005. 9. Campbell P, Mirra J, Doorn P, Mills B, Alim R, and Catelas I: Histopathology of Metal-on-Metal Hip Joint Tissues. IN Rieker C, Oberholzer S, Wyss U (eds). World Tribology Forum in Arthroplasty, Hans Huber, Gottingen, 2000, 167-180. 10. Campbell P, Beaule P, Ebramzadeh E, Le Duff M, De Smet K, Lu Z, and Amstutz H: A study of implant failure in metal-on-metal surface arthroplasties. Clin Orthop 453:35-46, 2006. 11. Campbell P, Shimmin A, Walter L, and Solomon M: Metal Sensitivity as a Cause of Groin Pain in Metal-on-Metal Hip Resurfacing. J Arthroplasty in press:2007. 12. Hallab NJ. Lymphocyte transformation testing for quantifying metal-implant-related hypersensitivity responses. Dermatitis. 2004;15:82-90.Pat Campbell, Ph.D. Director, Implant Retrieval Lab. J. Vernon Luck, Sr., MD Orthopaedic Research Center, UCLA/ Orthopedic Hospital Scott D. Nelson MD, Chief of Pathology Santa Monica UCLA/ Orthopedic Hospital