title: Improving acetabular cup orientation in total hip arthroplasty by using smartphone technology.
abstract: Acetabular cup placement in total hip arthroplasty is often difficult to assess, especially in the lateral position and using the posterior approach. Conventional techniques and computer-assisted surgery are the 2 most popular methods for proper placement of the acetabular cup in Lewinnek's safe zone of orientation (anteversion 15° ± 10° and lateral inclination 40° ± 10°). We developed a system that uses the accelerometer and camera function of the iPhone. A level indicator application and protractor application were downloaded to the iPhone and used to improve acetabular cup placement. This system has proven to be accurate and quick. Our series of 50 prospective cases showed good results with all our acetabular cups being placed within a narrow range in the safe zone and with less than 5% difference between the preoperative, intraoperative, and postoperative acetabular inclinations.
authors.affiliation: Department of Orthopaedic Surgery, Chris Hani Baragwanath Academic Hospital, University of the Witwatersrand, Johannesburg, South Africa.
authors.forename: Frank M
authors.initials: FM
authors.lastname: Peters
authors.forename: Richard
authors.initials: R
authors.lastname: Greeff
authors.forename: Neal
authors.initials: N
authors.lastname: Goldstein
authors.forename: Chris T
authors.initials: CT
authors.lastname: Frey
mesh_terms: D061725:Accelerometry; D000077:Acetabulum / Q000000981:diagnostic imaging / Q000601:surgery*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation* / Q000379:methods*; D060750:Bone Anteversion / Q000000981:diagnostic imaging / Q000517:prevention & control; D017760:Bone Malalignment / Q000000981:diagnostic imaging / Q000517:prevention & control; D040421:Cell Phone; D005260:Female; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011859:Radiography; D012189:Retrospective Studies; D012307:Risk Factors; D018805:Sepsis / Q000453:epidemiology; D025321:Surgery, Computer-Assisted / Q000295:instrumentation / Q000379:methods; D013997:Time Factors; D016896:Treatment Outcome