title: Classification of acetabular changes in osteoarthritis: a histological and radiological analysis of 122 consecutive drill biopsies routinely taken during THA.
abstract: BACKGROUND
  Aseptic acetabular loosening cannot be explained with a single theory and lots of studies deal with the influence of implant design and surgical technique on implant survival. Implant registers show the effect of demographic and patient-related parameters on acetabular loosening. There is little information about the influence of the acetabular bone quality on cup loosening.
  
  
  METHODS
  In a prospective study, we investigated the first 122 consecutive routinely taken biopsies out of acetabular bone stock taken during primary total hip arthroplasty (THA) before reaming of the cup. Undecalcified bone samples should be classified in respect to architecture and vitality in different histological types. Four types were defined and the primary diagnosis and the severity of the preoperative radiological changes were correlated to this classification.
  
  
  RESULTS
  A total number of 110 (90%) out of 122 biopsies could be classified to one specific type of biopsy, nine were not classifiable and three showed special entities [rheumatoid arthritis (RA) and coxitis]. Double examination showed a high intraobserver agreement (kappa 0.972). There was a correlation between the four defined types of bone biopsies and the radiological severity of osteoarthritis (P<0.0001) but not with the diagnosis (P=0.104).
  
  
  CONCLUSIONS
  Histological changes during the development of osteoarthritis of the hip occur regularly, can be classified in four groups and are predictable from radiological changes on preoperative radiographs.
authors.affiliation: Orthopedic Department, Kantonsspital Liestal, Rheinstrasse 26, 4410, Liestal, Switzerland. martin.clauss@ksli.ch
authors.forename: Martin
authors.initials: M
authors.lastname: Clauss
authors.forename: Thomas
authors.initials: T
authors.lastname: Ilchmann
authors.forename: Peter
authors.initials: P
authors.lastname: Zimmermann
authors.forename: Matthias U
authors.initials: MU
authors.lastname: Schafroth
authors.forename: Martin
authors.initials: M
authors.lastname: Lüem
authors.forename: Peter E
authors.initials: PE
authors.lastname: Ochsner
mesh_terms: D000077:Acetabulum / Q000000981:diagnostic imaging* / Q000473:pathology / Q000648:ultrastructure; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D019644:Arthroplasty, Replacement, Hip; D001706:Biopsy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000145:classification / Q000000981:diagnostic imaging* / Q000473:pathology*; D011446:Prospective Studies; D011859:Radiography; D016059:Range of Motion, Articular; D012720:Severity of Illness Index