PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 15963616

A comparative study between axial compression and lateral fall configuration tested in a rat proximal femur model.

Ge Zhang·Ling Qin·Yinyu Shi·Kwoksui Leung
View original source ↗Export metadata ↓

Abstract

BACKGROUND: Conventional testing method for evaluation of rat hip failure force is based on an axial compression approach. However, as the most osteoporotic hip fractures are a result of a lateral fall, it is necessary to establish mechanical testing methods more close to clinical conditions. This study was therefore designed to evaluate the differences in hip mechanical failure force to be tested between 'axial compression' and 'lateral fall configuration' in a rat proximal femur model. METHODS: Eighteen 10-month-old female Wistar rats were body-weight matched and divided into ovariectomized group (n = 9) and sham group (n = 9). All rats were euthanized 3 months after surgery. The bilateral proximal femora of each rat were excised. The left femur served for testing to failure in a fall configuration fashion while the right femur was tested using axial compression approach. After mechanical testing, the anterior-posterior radiographs were taken to identify the fracture mode and measure the Pauwel's angle between the fracture line and the line perpendicular to the femoral shaft long axis. FINDINGS: The failure force in fall configuration was significantly correlated with but lower than that tested in axial compression. A comparison between the ovariectomized and sham group showed that the failure force in both fall configuration and axial compression was found significantly higher in the sham group than that in the ovariectomized group. However, the logistic regression analysis revealed that the fall configuration approach had larger discrimination power. Radiographs showed that almost all samples fractured at the base of the femur neck. The Pauwel's angle in fall configuration group was significantly larger than that in axial compression group. INTERPRETATION: In comparison with the characteristics of axial compression test, the fall configuration approach generated higher shearing stress with larger bending moment to the bone and induced susceptibility to fracture at lower mechanical load. Although the failure force obtained from the two testing configurations revealed significant correlation, the mechanical testing in fall configuration demonstrated higher sensitivity in identifying the estrogen-deficiency induced deterioration of hip mechanical failure force as compared with that in axial compression. These findings suggested the potential application of lateral fall configuration in evaluation of improvement effects of intervention stratagems on hip mechanical failure force involving an ovariectomized rat model.

Explore related subjects

Accidental FallsAnimalsCompressive StrengthFemaleFemoral FracturesOsteoporosisOvariectomyRatsRats, WistarStress, MechanicalComparative StudyJournal ArticleResearch Support, Non-U.S. Gov't

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Ge Zhang, Ling Qin, Yinyu Shi, Kwoksui Leung. 2005. A comparative study between axial compression and lateral fall configuration tested in a rat proximal femur model.. https://doi.org/10.1016/j.clinbiomech.2005.03.016

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2007

Escitalopram in the long-term treatment of major depressive disorder in elderly patients.

AIM: The primary aim was to investigate the long-term safety and tolerability of escitalopram (10 or 20 mg/day) treatment of elderly patients suffering from major depressive disorder. The secondary aim was to examine response to treatment, as measured by change in the Montgomery-Asberg Depression Rating Scale (MADRS) total score from study entry to each visit, using observed cases. METHOD: This extension trial included 225 patients who had completed an 8-week, double blind, placebo-controlled lead-in study, which was performed in outpatients in primary care and in specialist clinics. The intent-to-treat population comprised 223 patients. RESULTS: The overall withdrawal rate was 24%. The most common reason for withdrawal was adverse events (9%). The 5 most common adverse events were accidental injury, rhinitis, weight increase, arthralgia and coughing, with an incidence ranging from 8 to 13%. No new types of adverse events were reported in this extension study compared to the 8-week lead-in study. The mean weight increased from 69.7 kg at study entry to 70.3 kg at endpoint. The percentage of patients in remission (MADRS total score < or = 12) increased from 48% at study entry to 72% by week 52. CONCLUSION: Escitalopram demonstrated a favourable tolerability profile during 52 weeks of open-label treatment of elderly patients, with further improvement in depressive symptoms.

Accidental Falls↗
PubMed2007

MRI of rupture of the spring ligament complex with talo-cuboid impaction.

The spring ligament complex is essential for the stability of the longitudinal arch of the foot and includes the ligaments between the calcaneus and the talus at the superomedial to inferoplantar aspect of the foot. Tears of the spring ligament complex are most commonly degenerative in etiology and secondary to concomitant abnormality of the posterior tibial tendon. We report MRI findings in a 30-year-old man who presented with traumatic rupture of the spring ligament complex, seen following dislocation of the talonavicular joint. We also describe the previously unreported MRI features of talo-cuboid impaction secondary to disruption of the spring ligament complex.

Accidental Falls↗