title: Effects of impaction on cement mantle and trabecular bone in hip resurfacing.
abstract: BACKGROUND
  Failures involving the femoral part in hip resurfacing remain problematic in terms of overall implant survival. In this context, effects of impaction strength on cement mantle morphology and trabecular bone damage have not been studied to date.
  
  
  METHODS
  Sixteen paired cadaveric femora that had undergone hard and gently impacted hip resurfacing using a manual packing cementing technique in a previous study, were evaluated morphologically. The earlier study had revealed lower failure loads for hard impacted heads. A central slice of each femoral head underwent microradiography.
  
  
  RESULTS
  Overall cement mantle thickness averaged 2.0 mm (range 0-5 mm) in the hard and in the low impact group with no significant difference between groups (p = 0.299). No signs of damage in the bone remnants inside the prosthesis of the fractured proximal femurs were detected in the microradiographic analysis.
  
  
  CONCLUSIONS
  Cement mantle thickness was not influenced by impaction strength when using a manual packing cementing technique. No trabecular damage underneath the implant was detected despite lower failure loads, confirming the difficulty to identify small trabecular damage in an in vitro study.
authors.affiliation: Department of Orthopaedic and Trauma Surgery, University of Cologne, Joseph-Stelzmann-Str. 9, 50924 Cologne, Germany. ulf.schlegel@gmx.net
authors.forename: Ulf J
authors.initials: UJ
authors.lastname: Schlegel
authors.forename: Jutta
authors.initials: J
authors.lastname: Knifka
authors.forename: Marc
authors.initials: M
authors.lastname: Röllinghoff
authors.forename: Jürgen
authors.initials: J
authors.lastname: Koebke
authors.forename: Peer
authors.initials: P
authors.lastname: Eysel
authors.forename: Michael M
authors.initials: MM
authors.lastname: Morlock
mesh_terms: D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D001843:Bone Cements; D002484:Cementation / Q000379:methods; D006622:Hip Prosthesis; D006801:Humans; D008852:Microradiography; D011475:Prosthesis Failure
chemical_list: D001843:Bone Cements