[Sequential changes in biomechanical competence of femoral neck and marrow cavity of proximal femur in ovariectomized rats].
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.
Wang
Jian-wei
JW
Department of Orthopaedics, The Second Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310009, China.
Li
Wei
W
Xu
Shao-wen
SW
Yang
Di-Sheng
DS
Zhao
Guang-feng
GF
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