title: Does osteoporosis reduce the primary tilting stability of cementless acetabular cups?
abstract: BACKGROUND
  Cementless hip cups need sufficient primary tilting stability to achieve osseointegration. The aim of the study was to assess differences of the primary implant stability in osteoporotic bone and in bone with normal bone density. To assess the influence of different cup designs, two types of threaded and two types of press-fit cups were tested.
  
  
  METHODS
  The maximum tilting moment for two different cementless threaded cups and two different cementless press-fit cups was determined in macerated human hip acetabuli with reduced (n=20) and normal bone density (n=20), determined using Q-CT. The tilting moments for each cup were determined five times in the group with reduced bone density and five times in the group with normal bone density, and the respective average values were calculated.
  
  
  RESULTS
  The mean maximum extrusion force of the threaded cup Zintra was 5670.5 N (max. tilting moment 141.8 Nm) in bone with normal density and.5748.3 N (max. tilting moment 143.7 Nm) in osteoporotic bone. For the Hofer Imhof (HI) threaded cup it was 7681.5 N (192.0 Nm) in bone with normal density and 6828.9 N (max. tilting moment 170.7 Nm) in the group with osteoporotic bone. The mean maximum extrusion force of the macro-textured press-fit cup Metallsockel CL was 3824.6 N (max. tilting moment 95.6 Nm) in bone with normal and 2246.2 N (max. tilting moment 56.2 Nm) in osteoporotic bone. For the Monoblock it was 1303.8 N (max. tilting moment 32.6 Nm) in normal and 1317 N (max. tilting moment 32.9 Nm) in osteoporotic bone. There was no significance. A reduction of the maximum tilting moment in osteoporotic bone of the ESKA press-fit cup Metallsockel CL was noticed.
  
  
  CONCLUSIONS
  Results on macerated bone specimens showed no statistically significant reduction of the maximum tilting moment in specimens with osteoporotic bone density compared to normal bone, neither for threaded nor for the press-fit cups. With the limitation that the results were obtained using macerated bone, we could not detect any restrictions for the clinical indication of the examined cementless cups in osteoporotic bone.
authors.affiliation: Department of Orthopedic and Trauma Surgery, Ruhr-University Bochum, St. Josef Hospital, Gudrunstrasse 56, 44791, Bochum, Germany. C.pellengahr@arcor.de.
authors.forename: Christoph
authors.initials: C
authors.lastname: von Schulze Pellengahr
authors.affiliation: Faculty of Health, University of Witten/Herdecke, Alfred-Herrhausen-Str. 50, 58448, Witten, Germany. larsvictor@gmx.de.|Department of Orthopedics, Trauma Surgery and Sports Medicine, Johanna Etienne Hospital, Am Hasenberg 46, 41462, Neuss, Germany. larsvictor@gmx.de.
authors.forename: Lars V
authors.initials: LV
authors.lastname: von Engelhardt
authors.affiliation: Department of Orthopaedic Surgery, University Hospital of Munich (LMU), Campus Großhadern, Marchioninistr. 15, 81377, München, Germany. Bernd.Wegener@med.uni-muenchen.de.
authors.forename: Bernd
authors.initials: B
authors.lastname: Wegener
authors.affiliation: Department of Orthopaedic Surgery, University Hospital of Munich (LMU), Campus Großhadern, Marchioninistr. 15, 81377, München, Germany. peter.mueller@med.uni-muenchen.de.
authors.forename: Peter E
authors.initials: PE
authors.lastname: Müller
authors.affiliation: Department of Orthopaedic Surgery, University Hospital of Munich (LMU), Campus Großhadern, Marchioninistr. 15, 81377, München, Germany. Andreas.Fottner@med.uni-muenchen.de.
authors.forename: Andreas
authors.initials: A
authors.lastname: Fottner
authors.affiliation: Department of Orthopaedic Surgery, University Hospital of Munich (LMU), Campus Großhadern, Marchioninistr. 15, 81377, München, Germany. Patrick.Weber@med.uni-muenchen.de.
authors.forename: Patrick
authors.initials: P
authors.lastname: Weber
authors.affiliation: Department of Orthopedic and Trauma Surgery, Klinikum Duisburg GmbH, Zu den Rehwiesen 9-11, 47055, Duisburg, Germany. Ole.Ackermann@Sana.de.
authors.forename: Ole
authors.initials: O
authors.lastname: Ackermann
authors.affiliation: Department of Orthopedic and Trauma Surgery, Ruhr-University Bochum, St. Josef Hospital, Gudrunstrasse 56, 44791, Bochum, Germany. M.Lahner@Klinikum-Bochum.de.
authors.forename: Matthias
authors.initials: M
authors.lastname: Lahner
authors.affiliation: Department of Orthopedic and Trauma Surgery, Ruhr-University Bochum, St. Josef Hospital, Gudrunstrasse 56, 44791, Bochum, Germany. W.Teske@Klinikuim-Bochum.de.
authors.forename: Wolfram
authors.initials: W
authors.lastname: Teske
mesh_terms: D000077:Acetabulum / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects / Q000295:instrumentation*; D001696:Biomechanical Phenomena; D015519:Bone Density; D002102:Cadaver; D016022:Case-Control Studies; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D006622:Hip Prosthesis; D006801:Humans; D016348:Osseointegration; D010024:Osteoporosis / Q000000981:diagnostic imaging / Q000503:physiopathology*; D011474:Prosthesis Design; D011475:Prosthesis Failure; D016059:Range of Motion, Articular; D012307:Risk Factors; D014057:Tomography, X-Ray Computed