Femoral neck narrowing after metal-on-metal hip resurfacing.
We reviewed 40 Corin Cormet 2000 (Corin, Cirencester, UK) metal-on-metal resurfacing hips, in 36 patients, for the presence of femoral neck narrowing. A neck-to-prosthesis ratio was calculated by dividing the diameter of the femoral neck with that of the implant. This ratio was measured on plain anteroposterior pelvis radiographs taken immediately and 2 years postoperation. Subsequent radiographs were measured up to a maximum 7 years (mean, 5.3 years) postoperation. Femoral neck narrowing was observed in 90% of hips at 2 years, with the average neck narrowing ranging from a ratio of 0.865 to 0.811. Importantly, no further narrowing occurred beyond this point up to 7 years postoperation. We described a simple reproducible method of measuring neck narrowing on plain radiographs and discuss possible causal factors for neck narrowing after hip resurfacing.
Department of Orthopaedic Surgery, Southern General Hospital, Glasgow, United Kingdom.
Simon
S
Spencer
Robert
R
Carter
Helen
H
Murray
R M Dominic
RM
Meek
D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation*; D005260:Female; D005265:Femoral Neck Fractures / Q000000981:diagnostic imaging; D005272:Femur Neck / Q000000981:diagnostic imaging* / Q000473:pathology; D005500:Follow-Up Studies; D006622:Hip Prosthesis; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008670:Metals; D008875:Middle Aged; D011475:Prosthesis Failure; D011859:Radiography; D012189:Retrospective Studies
D008670:Metals