[Iatrogenic "metalloma" (titanoma) caused by implant failure in "metal-backed" patellar joint surface replacement].
Patellofemoral problems frequently provide the cause for revisions after total knee replacements (TKR). Problems with metal-backed patellae, in particular, have been reported on in the past, with a failure rate of 33%. As a result of implant failure, there is an increase of polyethylene and metallic wear, which eventually leads to a synovialitis and metallosis. We report a case of a iatrogenic induced metallosis of the knee joint resulting from failure of a metal-backed patella component with the formation of a substantial pseudotumor within the popliteal fossa. Intraoperatively, a browny-grey, knotted and hard structure was to be seen, which histologically imposed as a hyalinated scar tissue with black particular deposits. Energy dispersive X-ray microanalysis showed a high level of titanium within the intra- and extracellular deposits. In differential diagnosis these findings were postulated as "metalloma" (titanoma). In cases of periprosthetic pseudotumors, particular those with implant failure, a iatrogenic-induced metalloma should be considered.
Büttner-Janz
Karin
K
Orthopädische Klinik, Vivantes Klinikum Hellersdorf, Myslowitzer Strasse 45, 12621 Berlin. orthopaedie@kh-hellersdorf.de
Müller
M
M
Müller
K M
KM
Friemann
J
J
D000328:Adult; D000497:Alloys; D015745:Granuloma, Foreign-Body / Q000000981:diagnostic imaging / Q000601:surgery*; D006801:Humans; D007049:Iatrogenic Disease; D007595:Joint Prosthesis / Q000009:adverse effects*; D007718:Knee Injuries / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000601:surgery*; D010329:Patella / Q000601:surgery*; D011183:Postoperative Complications / Q000000981:diagnostic imaging / Q000601:surgery*; D011474:Prosthesis Design; D011475:Prosthesis Failure; D011859:Radiography; D012086:Reoperation; D014025:Titanium / Q000009:adverse effects*
D000497:Alloys; C031462:titanium alloy (TiAl6V4); D014025:Titanium