title: No increased stem subsidence after arthroplasty in young patients with femoral head osteonecrosis: 41 patients followed for 1-9 years.
abstract: BACKGROUND
  Poor bone stock in patients with osteonecrosis of the femoral head may be a reason for poor outcome after hip replacement. One way of studying bone quality is to measure implant migration. We thus investigated the clinical and radiographic results of cementless THR in younger patients with femoral head osteonecrosis.
  
  
  METHODS
  We studied hips in 41 patients (mean age 48 (25-63) years) with a cementless hip arthroplasty after late stage osteonecrosis. Clinical evaluation was by the Harris hip score, the WOMAC score and the SF-36 score. Stem subsidence was measured with the Ein Bild Roentgen Analyse femoral component analysis (EBRA-FCA) at 3, 12, 24, 60, and 72 months after operation. The average duration of follow-up was 7(1-9) years, with less than 2 years for 2 patients.
  
  
  RESULTS
  There was no revision of any hip. No radiographic or clinical stem loosening was seen. After 60 months, the cementless stems showed a median subsidence of -0.7 mm (95% CI: -0.9 to -0.2). No femoral osteolysis occurred. Femoral radiolucent lines, all < 1 mm, were seen in 10 hips. At the latest follow-up the Harris hip score was 83 (23-100) points.
  
  
  CONCLUSIONS
  Our findings for porous-coated stems in patients with femoral osteonecrosis indicate no greater risk of stem subsidence and rate of osteolysis after an average of 7 years follow-up. Thus, we continue to use uncemented stems in younger patients with femoral osteonecrosis. However, continued follow-up will be necessary to evaluate the long-term outcome.
authors.affiliation: Department of Orthopaedic Surgery, University Hospital Würzburg, Würzburg, Germany. akif_ince@hotmail.com
authors.forename: Akif
authors.initials: A
authors.lastname: Ince
authors.forename: Johannes
authors.initials: J
authors.lastname: Lermann
authors.forename: Sascha
authors.initials: S
authors.lastname: Göbel
authors.forename: Nicole
authors.initials: N
authors.lastname: Wollmerstedt
authors.forename: Christian
authors.initials: C
authors.lastname: Hendrich
mesh_terms: D000328:Adult; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects; D005260:Female; D005271:Femur Head Necrosis / Q000000981:diagnostic imaging / Q000601:surgery*; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011475:Prosthesis Failure; D011859:Radiography; D016896:Treatment Outcome