title: [Total arthroplasty of the hip with a screwed titanium ring cup. Follow-up of 446 prostheses over four years].
abstract: The current decrease of total hip arthroplasty using a cemented polyethylene cup point out that bone-cement interface and polyethylene wear are two weak points responsible for long term loosening. Alumina-alumina combination can avoid one of the weak points. But fixing an alumina cup with cement doesn't avoid the second one. So from 1983 we have been using a cup composed by a titanium alloy threaded ring with an alumina insert. From the 508 prosthesis we fixed in between 1983 and 1989, 446 have been followed up over one year with an average follow-up 4 +/- 1.6 years. The patients mean age was 61.7 +/- 12 years. 368 were primary THA performed mostly for osteoarthrosis, 78 were performed in revision cases of cemented cup. All the femoral stems were cemented, we noted only two loosenings. The clinical results were satisfactory in primary arthroplasties (90.7 per cent satisfactory results in the R. Merle d'Aubigné and M. Postel scoring system), whereas in revision cases of cemented cups the percentage of non satisfactory results (32.8 per cent) was very high. Nevertheless migration rate of the threaded rings was 13 per cent (n = 48/368) in primary operation. 8.11 per cent when no structural graft was needed, 22.8 per cent when grafted. Although only 17/48 have been revised up to now, the future of the last 31 remain uncertain. In our opinion, the threaded cup should not be used in revision cases of cemented cups. The long term fixation of a threaded cup remains a problem for the dysplasic acetabula. For the non dysplasic non operated acetabula the migration factors are statistically: female sex, osteoporosis whatever the aetiology, a wrong primary positioning (cup too vertical, protrusio). For all these reasons, from 1989 we have been using a press-fit titanium cup, with promising results.
authors.affiliation: Service d'Orthopédie-Traumatologie, Hôpital Saint Louis, Paris.
authors.forename: J
authors.initials: J
authors.lastname: Witvoët
authors.forename: Z
authors.initials: Z
authors.lastname: Darman
authors.forename: P
authors.initials: P
authors.lastname: Christel
authors.forename: F
authors.initials: F
authors.lastname: Fumery
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001863:Bone Screws; D005260:Female; D005500:Follow-Up Studies; D006622:Hip Prosthesis / Q000009:adverse effects / Q000379:methods*; D006801:Humans; D007432:Intraoperative Period; D008297:Male; D008875:Middle Aged; D009984:Orthopedic Fixation Devices; D011184:Postoperative Period; D011475:Prosthesis Failure; D012086:Reoperation; D013997:Time Factors; D014025:Titanium
chemical_list: D014025:Titanium
vernacular_title: Arthoplastie totale de hanche avec anneau cotyloïdien en titane vissé. Devenir de 446 prothèses avec un recul moyen de 4 ans.