title: Movement pattern of the Exeter femoral stem; a radiostereometric analysis of 22 primary hip arthroplasties followed for 5 years..
abstract: BACKGROUND
  The design of the Exeter stem may facilitate distal migration, but radiostereometric analysis (RSA) studies have been limited to 2 years of follow-up.
  
  
  METHODS
  We followed migration of the Exeter femoral stems in 22 primary hip arthroplasties for 5 years with RSA.
  
  
  RESULTS
  All stems migrated distally and the median migration at 2 years was 1.34 mm, while at 5 years it was 1.77 mm. 7 stems migrated above accuracy between 3 and 5 years. (RSA) evaluation of the cement mantle could be performed in 14 cases, and in 5 slight migration was found. Most of the stems rotated towards retroversion and the median rotation at 2 years was 1.2 degrees, while at 5 years it was 1.6 degrees. We found 1 patient with impending clinical failure but no deviation in the RSA migration pattern, and 1 patient with unstable migration pattern but no clinical symptoms.
  
  
  CONCLUSIONS
  We found a greater distal migration of the Exeter stem for longer periods of time than seen with other types of cemented implants.
authors.affiliation: Department of Orthopedics, Hässleholm-Kristianstad County Hospital, Sweden. anna.stefansdottir@ort.lu.se
authors.forename: Anna
authors.initials: A
authors.lastname: Stefánsdóttir
authors.forename: Herbert
authors.initials: H
authors.lastname: Franzén
authors.forename: Ragnar
authors.initials: R
authors.lastname: Johnsson
authors.forename: Ewald
authors.initials: E
authors.lastname: Ornstein
authors.forename: Martin
authors.initials: M
authors.lastname: Sundberg
mesh_terms: D000328:Adult; D000368:Aged; D001696:Biomechanical Phenomena; D005260:Female; D005500:Follow-Up Studies; D005548:Foreign-Body Migration / Q000000981:diagnostic imaging*; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000000981:diagnostic imaging* / Q000601:surgery*; D011474:Prosthesis Design; D011475:Prosthesis Failure; D011859:Radiography; D013997:Time Factors