title: Relative head size increase using an anatomic dual mobility hip prosthesis compared to traditional hip arthroplasty: impact on hip stability.
abstract: Smaller head sizes and head/cup ratios make cups smaller than 50mm and larger than 58mm, more prone to dislocation. Using computer modeling, we compared average head sizes and posterior horizontal dislocation distance (PHDD) in two 78-patient matched cohorts. Cup sizes were small (≤50mm) or large (≥58mm). The control cohort had conventional fixed bearing prostheses, while the experimental cohort had anatomical dual mobility (ADM) hip prostheses. ADM cups have larger average head sizes and PHDD than traditional fixed bearing prostheses by 11.5mm and 80% for cups ≤50mm, and 16.3mm and 90% for cups ≥58mm. Larger head sizes and increased head/cup ratio may allow the ADM prosthesis to reduce the incidence of dislocation.
authors.affiliation: Hospital for Special Surgery, Department of Orthopaedic Surgery, New York, New York.
authors.forename: Michele R
authors.initials: MR
authors.lastname: D'Apuzzo
authors.affiliation: Stryker Orthopaedics, 325 Corporate Drive, Mahwah, New Jersey.
authors.forename: Jim
authors.initials: J
authors.lastname: Nevelos
authors.affiliation: Hospital for Special Surgery, Department of Orthopaedic Surgery, New York, New York.
authors.forename: Alyssa
authors.initials: A
authors.lastname: Yeager
authors.affiliation: Hospital for Special Surgery, Department of Orthopaedic Surgery, New York, New York.
authors.forename: Geoffrey H
authors.initials: GH
authors.lastname: Westrich
mesh_terms: D000077:Acetabulum / Q000033:anatomy & histology / Q000601:surgery; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D003198:Computer Simulation; D005260:Female; D005270:Femur Head / Q000033:anatomy & histology / Q000601:surgery*; D006617:Hip Dislocation / Q000209:etiology* / Q000517:prevention & control; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D007593:Joint Instability / Q000209:etiology* / Q000517:prevention & control; D008297:Male; D008875:Middle Aged; D016059:Range of Motion, Articular; D012189:Retrospective Studies
keywords: acetabular shell; anatomic dual mobility; dislocation; femoral head size; hip arthroplasty; posterior horizontal dislocation distance