Good stability of a cementless, anatomically designed femoral stem in aging women: a 9-year RSA study of 32 patients

Acta Orthop. 2018 Oct;89(5):490-495. doi: 10.1080/17453674.2018.1490985. Epub 2018 Jul 10.

Abstract

Background and purpose - We previously reported a transient, bone mineral density (BMD)-dependent early migration of anatomically designed hydroxyapatite-coated femoral stems with ceramic-ceramic bearing surfaces (ABG-II) in aging osteoarthritic women undergoing cementless total hip arthroplasty. To evaluate the clinical significance of the finding, we performed a follow-up study for repeated radiostereometric analysis (RSA) 9 years after surgery. Patients and methods - Of the 53 female patients examined at 2 years post-surgery in the original study, 32 were able to undergo repeated RSA of femoral stem migration at a median of 9 years (7.8-9.3) after surgery. Standard hip radiographs were obtained, and the subjects completed the Harris Hip Score and Western Ontario and McMaster Universities Osteoarthritis Index outcome questionnaires. Results - Paired comparisons revealed no statistically significant migration of the femoral stems between 2 and 9 years post-surgery. 1 patient exhibited minor but progressive RSA stem migration. All radiographs exhibited uniform stem osseointegration. No stem was revised for mechanical loosening. The clinical outcome scores were similar between 2 and 9 years post-surgery. Interpretation - Despite the BMD-related early migration observed during the first 3 postoperative months, the anatomically designed femoral stems in aging women are osseointegrated, as evaluated by RSA and radiographs, and exhibit good clinical function at 9 years.

MeSH terms

  • Adult
  • Aged
  • Arthroplasty, Replacement, Hip / instrumentation*
  • Arthroplasty, Replacement, Hip / methods
  • Bone Diseases, Metabolic / complications
  • Bone Diseases, Metabolic / physiopathology
  • Female
  • Follow-Up Studies
  • Hip Joint / diagnostic imaging
  • Hip Joint / physiopathology
  • Hip Prosthesis*
  • Humans
  • Middle Aged
  • Osseointegration / physiology
  • Osteoarthritis, Hip / complications
  • Osteoarthritis, Hip / diagnostic imaging
  • Osteoarthritis, Hip / surgery*
  • Prosthesis Design
  • Prosthesis Failure
  • Radiostereometric Analysis