title: [Roentgen criteria and radiologic results of the Hofer-Imhof (H-I) threaded acetabulum cup in first time implantation].
abstract: The Hofer-Imhof cup consists of a parabola-shaped titanium acetabular component with flat threads. These flat threads are designed to be self-cutting and allow accurate insertion without incarceration, even in sclerotic bone. In a prospective study conducted from May 1988 to July 1989, 143 Hofer-Imhof cups were implanted. Radiographic assessment included initial bone contact, cup position, fixation on osteophytes, presence of any radiolucencies or sclerosis, cup migration and bone ingrowth. Initial prosthesis fit was evaluated with a 20 degrees caudally angled anteroposterior X-ray for accurate demonstration of the threads. 119 of the Hofer-Imhof cups (83.2%) were available for radiographic follow-up at a mean of 65 months (min. 37 mo., max. 95 mo.). One cup required revision after 23 months due to infection. The cups had an average inclination of 47 degrees, and complete bone contact was evident in 86.6% on the postoperative X-ray. In 8.4% of the cups, some threads were not in contact with bone at the edge of the acetabulum. At final follow-up, 82.4% had complete bone ingrowth without any evidence of radiolucency (type I), 15.1% had near-complete bone ingrowth with minimal radiolucencies (type II), and 2.5% had predominantly fibrous fixation (type III). One cup (0.8%) showed excessive migration. The technique of anchorage using a flat thread, minimal bone resection as a result of the parabolic shape and the sandblasted titanium surface are the characteristic features of the Hofer-Imhof threaded cup and produce good medium-term results in primary hip arthroplasty.
authors.affiliation: Orthopädische Abteilung, Landeskrankenanstalten Salzburg.
authors.forename: H
authors.initials: H
authors.lastname: Effenberger
authors.forename: M
authors.initials: M
authors.lastname: Weber
authors.forename: U
authors.initials: U
authors.lastname: Dorn
authors.forename: H
authors.initials: H
authors.lastname: Hofer
mesh_terms: D000077:Acetabulum / Q000000981:diagnostic imaging / Q000601:surgery*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005500:Follow-Up Studies; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D016348:Osseointegration / Q000502:physiology; D011095:Polyethylenes; D011183:Postoperative Complications / Q000000981:diagnostic imaging*; D011446:Prospective Studies; D011474:Prosthesis Design; D011475:Prosthesis Failure; D011859:Radiography; D014025:Titanium
chemical_list: D011095:Polyethylenes; D014025:Titanium