title: An in-vitro biomechanical study of different fixation techniques for the extended trochanteric osteotomy in revision THA.
abstract: BACKGROUND
  The wire fixation and the cable grip fixation have been developed for the extended trochanteric osteotomy (ETO) in the revision of total hip arthroplasty (THA). Many studies reported the postoperative performance of the patients, but with little quantitative biomechanical comparison of the two fixation systems.
  
  
  METHODS
  An in-vitro testing approach was designed to record the loosening between the femoral bed and the greater trochanter after fixations. Ten cadaveric femurs were chosen in this study. Each femur underwent the THA, revision by ETO and fixations. The tension to the greater trochanter was from 0 to 500N in vertical and lateral direction, respectively. The translation and rotation of the greater trochanter with respect to the bony bed were captured by an optical tracking system.
  
  
  RESULTS
  In the vertical tension tests, the overall translation of the greater trochanter was observed 0.4 mm in the cable fixations and 7.0 mm in the wire fixations. In the lateral tension tests, the overall motion of the greater trochanter was 2.0 mm and 1.2° in the cable fixations, while it was 6.2 mm and 5.3° in the wire fixations. The result was significantly different between the two fixation systems.
  
  
  CONCLUSIONS
  The stability of the proximal femur after ETO using different fixations in the revision THA was investigated. The cable grip fixation was significantly more stable than the wire fixation.
authors.affiliation: Department of Biomedical Engineering, Tsinghua University, Beijing, China.
authors.forename: Zhonglin
authors.initials: Z
authors.lastname: Zhu
authors.forename: Hui
authors.initials: H
authors.lastname: Ding
authors.forename: Hongyi
authors.initials: H
authors.lastname: Shao
authors.forename: Yixin
authors.initials: Y
authors.lastname: Zhou
authors.forename: Guangzhi
authors.initials: G
authors.lastname: Wang
mesh_terms: D000328:Adult; D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D001696:Biomechanical Phenomena; D001860:Bone Plates; D001864:Bone Wires; D005260:Female; D005269:Femur / Q000503:physiopathology / Q000601:surgery*; D006622:Hip Prosthesis; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D009038:Motion; D010027:Osteotomy / Q000379:methods*; D011475:Prosthesis Failure; D012086:Reoperation / Q000295:instrumentation / Q000379:methods; D012399:Rotation; D013314:Stress, Mechanical