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.
Spencer
Simon
S
Department of Orthopaedic Surgery, Southern General Hospital, Glasgow, United Kingdom.
Carter
Robert
R
Murray
Helen
H
Meek
R M Dominic
RM
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