Long-term bisphosphonate treatment coupled with ovariectomy in mice provokes deleterious effects on femoral neck fracture pattern and modifies tibial shape

Aims The processes linking long-term bisphosphonate treatment to atypical fracture remain elusive. To establish a means of exploring this link, we have examined how long-term bisphosphonate treatment with prior ovariectomy modifies femur fracture behaviour and tibia mass and shape in murine bones. Methods Three groups (seven per group) of 12-week-old mice were: 1) ovariectomized and 20 weeks thereafter treated weekly for 24 weeks with 100 μm/kg subcutaneous ibandronate (OVX+IBN); 2) ovariectomized (OVX); or 3) sham-operated (SHAM). Quantitative fracture analysis generated biomechanical properties for the femoral neck. Tibiae were microCT scanned and trabecular (proximal metaphysis) and cortical parameters along almost its whole length measured. Results Fracture analyses revealed that OVX+IBN significantly reduced yield displacement (vs SHAM/OVX) and resilience, and increased stiffness (vs SHAM). OVX+IBN elevated tibial trabecular parameters and also increased cortical cross-sectional area and second moment of area around minor axis, and diminished ellipticity proximally. Conclusion These data indicate that combined ovariectomy and bisphosphonate generates cortical changes linked with greater bone brittleness and modified fracture characteristics, which may provide a basis in mice for interrogating the mechanisms and genetics of atypical fracture aetiology. Cite this article: Bone Joint Open 2020;1-9:512–519.

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Impact of oral contraceptive use and menstrual phases on patellar tendon morphology, biochemical composition, and biomechanical properties in female athletes

Journal of Applied Physiology ◽

10.1152/japplphysiol.01255.2012 ◽

2013 ◽

Vol 114 (8) ◽

pp. 998-1008 ◽

Cited By ~ 19

Author(s):

Mette Hansen ◽

Christian Couppe ◽

Christina S. E. Hansen ◽

Dorthe Skovgaard ◽

Vuokko Kovanen ◽

...

Keyword(s):

Patellar Tendon ◽

Female Athletes ◽

Maximum Voluntary Contraction ◽

Biomechanical Properties ◽

Cross Sectional Area ◽

Cross Linking ◽

Sectional Area ◽

Cross Sectional ◽

Collagen Cross Linking

Sex differences exist with regards to ligament and tendon injuries. Lower collagen synthesis has been observed in exercising women vs. men, and in users of oral contraceptives (OC) vs. nonusers, but it is unknown if OC will influence tendon biomechanics of women undergoing regular training. Thirty female athletes (handball players, 18–30 yr) were recruited: 15 long-term users of OC (7.0 ± 0.6 yr) and 15 nonusers (>5 yr). Synchronized values of patellar tendon elongation (obtained by ultrasonography) and tendon force were sampled during ramped isometric knee extensor maximum voluntary contraction to estimate mechanical tendon properties. Furthermore, tendon cross-sectional area and length were measured from MRI images, and tendon biopsies were obtained for analysis of tendon fibril characteristics and collagen cross-linking. Overall, no difference in tendon biomechanical properties, tendon fibril characteristics, or collagen cross-linking was observed between the OC users and nonusers, or between the different phases of the menstrual cycle. In athletes, tendon cross-sectional area in the preferred jumping leg tended to be larger than that in the contralateral leg ( P = 0.09), and a greater absolute ( P = 0.01) and normalized tendon stiffness ( P = 0.02), as well as a lower strain ( P = 0.04), were observed in the jumping leg compared with the contralateral leg. The results indicate that long-term OC use or menstrual phases does not influence structure or mechanical properties of the patellar tendon in female team handball athletes.

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Comparative Analysis of Preoperative and Postoperative Muscle Around Hip Joint by Computed Tomography Between Intertrochanteric Fracture and Femur Neck Fracture

10.21203/rs.3.rs-65484/v1 ◽

2020 ◽

Author(s):

Sung Yoon Jung ◽

Hyeon Jun Kim ◽

Kyu Taek Oh

Keyword(s):

Femoral Neck ◽

Femoral Neck Fracture ◽

Intertrochanteric Fracture ◽

Femoral Neck Fractures ◽

Final Visit ◽

Cross Sectional ◽

Fracture Group ◽

Significant Difference ◽

Neck Fracture

Abstract Background:This study assessed the changes in hip muscles by comparing the preoperative and postoperative CT scan results between patients with intertrochanteric versus femoral neck fractures. Methods:48 patients who received surgical treatment for intertrochanteric or femoral neck fractures from February 2013 to February 2019 and underwent pelvic computed tomography(CT) preoperative and postoperatively aged 65 and older with a minimum follow-up of 1 year were included. The subjects were divided into two groups: 26 patients with intertrochanteric fracture and 22 patients with femoral neck fracture. We measured the cross-sectional area(CSA) and attenuation of the gluteus medius(G.med), gluteus minimus(G.min), iliopsoas(IP), and rectus femoris(RF) on the contralateral side. Patient basic data were collected from medial records including sex, age, height, weight, BMI, BMD, Harris hip score (HHS), and length of follow-up until the final visit. Results: There was no significant difference in sex, age, height, weight, BMI, BMD, HHS, and length of follow-up until the final visit between two groups. The femoral neck fracture group had significantly larger CSA and cross-sectional area per weight(CSA/Wt) of the G.med and G.min(G.med CSA, CSA/wt preoperative 1995.29 vs 1713.64, 38.87 vs 32.74; postoperative 2144.98 vs 1815.56, 37.48 vs 32.78/G.min preoperative 745.22 vs 566.59, 14.32 vs 10.96; postoperative 764.39 vs 619.17, 14.78 vs 11.25). On the contrary, the intertrochanteric fracture group had significantly greater CSA and CSA/Wt of the IP and RF(IP preoperative 810.86 vs 661.88, 17.73 vs 9.42; postoperative 681.98 vs 571.32, 12.68 vs 9.88/RF preoperative 503.66 vs 386.72, 9.42 vs 7.23; postoperative 426.24 vs 349.31, 7.17 vs 5.23). HHS related with function had no significant correlation with postoperative CSA and CSA/Wt. There was no significant difference in attenuation between two groups. All subjects had a significant decrease of muscle attenuation postoperatively.Conclusions: The CSA of the hip abductor(G.med and G.min) was significantly larger in the femoral neck fracture group, while the CSA of the hip flexor(IP and RF) was significantly higher in the intertrochanteric fracture group. Based on these findings, choosing the rehabilitation program suitable for the fracture site is expected to be beneficial in hip fracture rehabilitation.

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