title: [Sequential changes in biomechanical competence of femoral neck and marrow cavity of proximal femur in ovariectomized rats].
abstract: To observe the sequential changes in biomechanical competence of the femoral neck and marrow cavity of the proximal femur in ovariectomized rats.
  
  
  
  Bone mineral density (BMD) and biomechanical properties of the femoral neck and the structural dimension of the proximal femur were measured 0, 3, 6, 9, 12, 15, 18, 21 weeks after ovariectomy (OVX) or sham operation (Sham) in 6-month-old female SD rats.
  
  
  
  The BMD of femoral neck in OVX rats was significantly lower than that in Sham group 6 weeks after operation, (0.195 +/-0.028) g/mm(2) vs (0.225 +/-0.036) g/mm(2) (P=0.03). Nine weeks after operation,the failure load of femoral neck decreased about 10% in OVX group to that in Sham group, (89.6 +/-7.7)N vs (96.7 +/-7.5)N (P=0.05). The medullary cavity of proximal femur started to show difference 15 weeks after operation (3.834 +/-0.115)mm(2) vs (3.713 +/-0.114) mm(2) (P=0.03).
  
  
  
  BMD loss after ovariectomy is associated with a medullary expansion in proximal femur and biomechanical strength deterioration in femoral neck, which might be an important factor of prostheses loosening in the postmenopausal osteoporotic women.
authors.affiliation: Department of Orthopaedics, The Second Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310009, China.
authors.forename: Jian-wei
authors.initials: JW
authors.lastname: Wang
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.forename: Shao-wen
authors.initials: SW
authors.lastname: Xu
authors.forename: Di-Sheng
authors.initials: DS
authors.lastname: Yang
authors.forename: Guang-feng
authors.initials: GF
authors.lastname: Zhao
mesh_terms: D000818:Animals; D019644:Arthroplasty, Replacement, Hip; D001696:Biomechanical Phenomena; D015519:Bone Density; D005260:Female; D005269:Femur / Q000378:metabolism*; D005272:Femur Neck / Q000378:metabolism*; D006801:Humans; D015663:Osteoporosis, Postmenopausal; D010052:Ovariectomy; D011475:Prosthesis Failure; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley