title: Unconstrained tripolar implants for primary total hip arthroplasty in patients at risk for dislocation.
abstract: We performed a retrospective study on 167 primary total hip arthroplasty (THA) procedures in 163 patients at high risk for instability to assess the reliability of unconstrained tripolar implants (press-fit outer metal shell articulating a bipolar polyethylene component) in preventing dislocations. Eighty-four percent of the patients had at least 2 risk factors for dislocation. The mean follow-up length was 40.2 months. No dislocation was observed. Harris hip scores improved significantly. Six hips were revised, and no aseptic loosening of the cup was observed. The tripolar implant was extremely successful in achieving stability. However, because of the current lack of data documenting polyethylene wear at additional bearing, the routine use of tripolar implants in primary THA is discouraged and should be considered at the present time only for selected patients at high risk for dislocation and with limited activities.
authors.affiliation: Department of Orthopedic Surgery, Pavillon T, Hôpital Edouard Herriot, Lyon, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Guyen
authors.forename: Vincent
authors.initials: V
authors.lastname: Pibarot
authors.forename: Gualter
authors.initials: G
authors.lastname: Vaz
authors.forename: Christophe
authors.initials: C
authors.lastname: Chevillotte
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Carret
authors.forename: Jacques
authors.initials: J
authors.lastname: Bejui-Hugues
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation*; D005260:Female; D005500:Follow-Up Studies; D006617:Hip Dislocation / Q000517:prevention & control; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000517:prevention & control; D019736:Prostheses and Implants; D011475:Prosthesis Failure; D012189:Retrospective Studies; D012307:Risk Factors