title: [Does osteoporosis lead to reduction the primary stability of cementless hip cups?].
abstract: BACKGROUND
  Cementless hip cups require adequate primary stability in order to achieve osseointegration. Depending on implant design, a different biomechanical behavior in osteoporotic bone and in bone with normal bone mineral density might be expected.
  
  
  METHODS
  The micromovement between bone and implant was determined in macerated human hip acetabula with reduced and with normal bone density for two different cementless screwed cups and two different cementless press-fit cups. The bone mineral density was assessed by means of Q-CT and 20 implantations were performed for each acetabulum with reduced and with normal bone density.
  
  
  RESULTS
  Screwed cups showed significantly less micromovement than press-fit cups. The average micromovement of all cups, with the exception of the Monoblock cup, remained below the value of 100 µ, the upper limit for successful osseointegration. Values of over 200 µ were measured only for the Monoblock cup and only in some of the tests. There was no significant difference between the micro-movement in acetabula with reduced bone mineral density and with normal bone.
  
  
  CONCLUSIONS
  Impaired osseointegration in osteoporotic bone because of increased micromovement is not to be expected in the investigated cementless hip cups as no relevant differences in micromovement were found between normal and osteoporotic bone stock. On the basis of the good clinical results with the Monoblock cup, the upper limit of 100 µ of micromotion for osseointegation in macerated bone is probably set too low.
authors.affiliation: Orthopädische Universitätsklinik im St.-Josef-Hospital, Kliniken der Ruhruniversität Bochum, Gudrunstr. 56, 44791, Bochum, Deutschland. C.von-Schulze-Pellengahr@Klinikum-Bochum.de
authors.forename: C
authors.initials: C
authors.lastname: von Schulze-Pellengahr
authors.forename: A
authors.initials: A
authors.lastname: Bürkner
authors.forename: T
authors.initials: T
authors.lastname: Lichtinger
authors.forename: W
authors.initials: W
authors.lastname: Teske
authors.forename: A
authors.initials: A
authors.lastname: Fottner
authors.forename: B
authors.initials: B
authors.lastname: Wegener
authors.forename: T
authors.initials: T
authors.lastname: Vogel
mesh_terms: D000077:Acetabulum / Q000503:physiopathology / Q000601:surgery*; D001843:Bone Cements; D001863:Bone Screws; D006622:Hip Prosthesis; D006801:Humans; D016348:Osseointegration / Q000502:physiology*; D010024:Osteoporosis / Q000503:physiopathology / Q000601:surgery*; D011183:Postoperative Complications / Q000209:etiology* / Q000503:physiopathology; D011474:Prosthesis Design; D011475:Prosthesis Failure
chemical_list: D001843:Bone Cements