title: Technical factors for success with metal ring acetabular reconstruction.
abstract: Sixty-four hips in 62 patients were revised with a Mueller ring (28 hips), Ganz ring (18 hips), and Burch-Schneider cage (18 hips) under the direction of a single surgeon. A polyethylene cup was cemented into the metal support of all hips. Average follow-up was 4.6 years (range, 2.0-6.7 years). Six rings were revised because of aseptic loosening, and 5 others were radiographically loose, for a mechanical failure rate of 11 of 64 (17%). Acetabular metal ring supports failed by migration when defects of > or =60% of the superior weight-bearing bone were filled by only cement or particulate graft. At the time of surgery, the superior rim of the metal support should be against host-bone for 60% of its support, and if not, the use of bulk allograft, rather than particulate graft, is required. Dislocation was the second failure mechanism identified, and this occurred in 15 hips (23%), with reoperation required in 5 hips (8%). A constrained liner should be used in patients with nonunion of the trochanter and preoperative abductor weakness that grades fair/minus or worse as measured by the side-lying abduction test.
authors.affiliation: The Arthritis Institute at Centinela Hospital, Inglewood, California 90301, USA.
authors.forename: P
authors.initials: P
authors.lastname: Udomkiat
authors.forename: L D
authors.initials: LD
authors.lastname: Dorr
authors.forename: Y Y
authors.initials: YY
authors.lastname: Won
authors.forename: D
authors.initials: D
authors.lastname: Longjohn
authors.forename: Z
authors.initials: Z
authors.lastname: Wan
mesh_terms: D000077:Acetabulum / Q000601:surgery*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation / Q000379:methods*; D002484:Cementation; D016009:Chi-Square Distribution; D005260:Female; D005500:Follow-Up Studies; D006617:Hip Dislocation / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011095:Polyethylenes; D011183:Postoperative Complications / Q000453:epidemiology; D011475:Prosthesis Failure; D012086:Reoperation; D016896:Treatment Outcome
chemical_list: D011095:Polyethylenes