Movement pattern of the Exeter femoral stem; a radiostereometric analysis of 22 primary hip arthroplasties followed for 5 years

Acta Orthop Scand. 2004 Aug;75(4):408-14. doi: 10.1080/00016470410001169-1.

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.

Patients and 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.

Interpretation: We found a greater distal migration of the Exeter stem for longer periods of time than seen with other types of cemented implants.

MeSH terms

  • Adult
  • Aged
  • Biomechanical Phenomena
  • Female
  • Follow-Up Studies
  • Foreign-Body Migration / diagnostic imaging*
  • Hip Prosthesis*
  • Humans
  • Male
  • Middle Aged
  • Osteoarthritis, Hip / diagnostic imaging*
  • Osteoarthritis, Hip / surgery*
  • Prosthesis Design
  • Prosthesis Failure*
  • Radiography
  • Time Factors