"Asymptomatic" pseudotumors after metal-on-metal hip resurfacing arthroplasty: prevalence and metal ion study.
Symptomatic abnormal periprosthetic soft-tissue reactions ("pseudotumors") have been reported after metal-on-metal hip resurfacing arthroplasty (MoMHRA). The aims of this study were (1) to determine the prevalence of asymptomatic pseudotumors after MoMHRA and (2) to measure metal ion levels in these patients. A total of 201 hips in 158 patients were evaluated at a mean follow-up of 61 months (range, 36-88) using ultrasound/magnetic resonance imaging and serum/hip aspirate cobalt and chromium measurements. Pseudotumors found in 7 patients (4%) were associated with significantly higher cobalt and chromium levels and inferior functional scores. Elevated levels of cobalt and chromium ions suggest that pseudotumors are associated with increased wear generated from metal-on-metal articulations. Clinicians need to be aware of pseudotumors as a differential diagnosis during clinical evaluation of MoMHRA patients, and further imaging such as ultrasound or magnetic resonance imaging is recommended to confirm the diagnosis.
Kwon
Young-Min
YM
Department of Orthopaedic Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02116, USA.
Ostlere
Simon J
SJ
McLardy-Smith
Peter
P
Athanasou
Nicholas A
NA
Gill
Harinderjit S
HS
Murray
David W
DW
D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation*; D002857:Chromium / Q000009:adverse effects / Q000097:blood; D003035:Cobalt / Q000009:adverse effects / Q000097:blood; D005260:Female; D006104:Granuloma, Plasma Cell / Q000097:blood* / Q000175:diagnosis / Q000453:epidemiology*; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008670:Metals / Q000009:adverse effects* / Q000097:blood; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000601:surgery; D015995:Prevalence; D012189:Retrospective Studies; D017695:Soft Tissue Injuries / Q000097:blood* / Q000175:diagnosis / Q000453:epidemiology*; D014463:Ultrasonography
D008670:Metals; D002857:Chromium; D003035:Cobalt