title: Bone cement penetration pattern and primary stability testing in keeled and pegged glenoid components.
abstract: BACKGROUND
  It has been proposed that bone mineral density has an influence on cement penetration in hip and knee arthroplasty. The hypotheses of this study were that: 1) there is a negative correlation between bone mineral density (BMD) and cement penetration in cemented glenoid components; and 2) that implant design has an influence on cement penetration into the glenoid bone.
  
  
  METHODS
  BMD of 10 pairs of fresh frozen scapulas was measured. Micro-computed tomography (micro-CT) scans in 3 different sections were analyzed after implantation of keeled and pegged glenoid components using a 3(rd)-generation cementing technique with a vacuum mixing system. Cement penetration was analyzed and correlated with BMD. Pull-out strength testing was performed to analyze primary stability.
  
  
  RESULTS
  The overall peak BMD was 0.6 [g/cm(2)] (range, 0.33-0.98). A strong negative correlation between BMD and mean cement penetration was found for the peg (R(2) = -.83; P < .003) and for the keel group (R(2) = -.81; P < .005). Mean cement penetration was 78.4 mm(2) (range, 60.6-94.2) in the keel and 113.9 mm(2) (range, 78.2-143.4) in the peg group (P < .0001). In all cases, the components were pulled out of the cement mantle, whereas the bone-cement interfaces remained intact. The mean pull-out strength was 1093N (764-1343N) for keeled and 884N (650-1264N) for pegged components (P < .05).
  
  
  CONCLUSIONS
  A modern cementing technique, leading to a deep bonding between bone and cement, is crucial to prevent loosening of glenoid components. The findings of this study might help us to better understand the results of follow-up studies of cemented glenoid implants. Our results could be helpful for the choice of implants in patients with poor bone quality like osteoporosis or rheumatoid arthritis.
authors.affiliation: Orthopaedic Department, University of Heidelberg, Germany. Patric.Raiss@med.uni-heidelberg.de
authors.forename: Patric
authors.initials: P
authors.lastname: Raiss
authors.forename: Guido
authors.initials: G
authors.lastname: Pape
authors.forename: Kerstin
authors.initials: K
authors.lastname: Kleinschmidt
authors.forename: Sebastian
authors.initials: S
authors.lastname: Jäger
authors.forename: Boris
authors.initials: B
authors.lastname: Sowa
authors.forename: Eike
authors.initials: E
authors.lastname: Jakubowitz
authors.forename: Markus
authors.initials: M
authors.lastname: Loew
authors.forename: Thomas
authors.initials: T
authors.lastname: Bruckner
authors.forename: Markus
authors.initials: M
authors.lastname: Rickert
mesh_terms: D000328:Adult; D000368:Aged; D019643:Arthroplasty, Replacement / Q000379:methods*; D001843:Bone Cements; D006801:Humans; D007593:Joint Instability / Q000517:prevention & control*; D007595:Joint Prosthesis; D008875:Middle Aged; D010003:Osteoarthritis / Q000601:surgery*; D016059:Range of Motion, Articular / Q000502:physiology*; D012785:Shoulder Joint / Q000601:surgery*; D055815:Young Adult
chemical_list: D001843:Bone Cements