title: Cup position alone does not predict risk of dislocation after hip arthroplasty.
abstract: We used a large prospective institutional registry to determine if there is a 'safe zone' that exists for acetabular component position within which the risk of hip dislocation is low and if other patient and implant factors affect the risk of hip dislocation. Patients who reported a dislocation event within six months after hip arthroplasty surgery were identified, and acetabular component position was measured with anteroposterior radiographs. The frequency of dislocation was 2.1% (147 of 7040 patients). No significant difference was found in the number of dislocated hips among the radiographic zones (±5°,±10°,±15° boundaries). Dislocators <50 years old were less active preoperatively than nondislocators (P=0.006). Acetabular component position alone is not protective against instability.
authors.affiliation: Hospital for Special Surgery, New York, New York.
authors.forename: Christina I
authors.initials: CI
authors.lastname: Esposito
authors.affiliation: Hospital for Special Surgery, New York, New York.
authors.forename: Brian P
authors.initials: BP
authors.lastname: Gladnick
authors.affiliation: Hospital for Special Surgery, New York, New York.
authors.forename: Yuo-Yu
authors.initials: YY
authors.lastname: Lee
authors.affiliation: Hospital for Special Surgery, New York, New York.
authors.forename: Stephen
authors.initials: S
authors.lastname: Lyman
authors.affiliation: Hospital for Special Surgery, New York, New York.
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Wright
authors.affiliation: Hospital for Special Surgery, New York, New York.
authors.forename: David J
authors.initials: DJ
authors.lastname: Mayman
authors.affiliation: Hospital for Special Surgery, New York, New York.
authors.forename: Douglas E
authors.initials: DE
authors.lastname: Padgett
mesh_terms: D000077:Acetabulum / Q000000981:diagnostic imaging / Q000601:surgery*; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects* / Q000379:methods; D005260:Female; D006617:Hip Dislocation / Q000209:etiology / Q000517:prevention & control*; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011859:Radiography; D012042:Registries
keywords: arthroplasty; cup orientation; dislocation; hip; safe zone