Mixing and matching causing taper wear: corrosion associated with pseudotumour formation.
We report a case of a male patient presenting with bilateral painful but apparently well-positioned and -fixed large-diameter metal-on-metal hip replacements four years post-operatively. Multiple imaging modes revealed a thick-walled, cystic expansile mass in communication with the hip joint (a pseudotumour). Implant retrieval analysis and tissue culture eliminated high bearing wear or infection as causes for the soft-tissue reaction, but noted marked corrosion of the modular neck taper adaptor and corrosion products in the tissues. Therefore, we believe corrosion products from the taper caused by mismatch of the implant components led to pseudotumour formation requiring revision.
Specialist Orthopaedic Group, Mater Clinic, Suite 1.08, 3-9 Gillies Street, Wollstonecraft, New South Wales 2065, Australia. rishi.chana1@btopenworld.com
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Chana
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Walter
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D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects; D003343:Corrosion; D006104:Granuloma, Plasma Cell / Q000175:diagnosis / Q000209:etiology* / Q000473:pathology; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000473:pathology*; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D011475:Prosthesis Failure; D014057:Tomography, X-Ray Computed