title: Early- and late-term dislocation risk after primary hip arthroplasty in the Medicare population.
abstract: From 1998 to 2007 Medicare 5% national sample dataset, 39 271 primary total hip arthroplasty (THA) patients were identified. Dislocations within 2 years (early) and after 2 years (late) of primary THA were identified. Cox regression was used to evaluate patient, hospital, and procedure characteristics for risk of dislocation, and 1540 (3.92%) and 451 (1.15%) patients were diagnosed with early and late dislocations, respectively. Dislocation rate at 6 months' follow-up decreased steadily between 1998 and 2007 from 4.21% to 2.14%. Early and late dislocation risks were lower by 35% (P < .001) and 43% (P = .01), respectively, for patients operated during 2004 and 2007 compared with 1998 and 2003. Higher Charlson index scores (i.e., more comorbid conditions) and surgeon volume were significant risk factors (P < or = .04). Decrease in dislocation risks after primary THA seems to coincide with increasing use of larger diameter femoral heads. An awareness of risk factors for dislocation can help surgeons identify high-risk patients so as to prescribe appropriate intervention strategies.
authors.affiliation: University of Louisville, Department of Orthopaedic Surgery, Louisville, Kentucky 40202, USA.
authors.forename: Arthur L
authors.initials: AL
authors.lastname: Malkani
authors.forename: Kevin L
authors.initials: KL
authors.lastname: Ong
authors.forename: Edmund
authors.initials: E
authors.lastname: Lau
authors.forename: Steven M
authors.initials: SM
authors.lastname: Kurtz
authors.forename: Benjamin J
authors.initials: BJ
authors.lastname: Justice
authors.forename: Michael T
authors.initials: MT
authors.lastname: Manley
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects* / Q000191:economics / Q000295:instrumentation; D005270:Femur Head / Q000473:pathology; D017048:Health Care Costs; D006617:Hip Dislocation / Q000453:epidemiology*; D006622:Hip Prosthesis / Q000009:adverse effects* / Q000191:economics; D006801:Humans; D053208:Kaplan-Meier Estimate; D006278:Medicare / Q000191:economics; D011474:Prosthesis Design; D011475:Prosthesis Failure / Q000009:adverse effects*; D012044:Regression Analysis; D012189:Retrospective Studies; D012307:Risk Factors; D014481:United States