A weighted osteon morphotype score outperforms regional osteon percent prevalence calculations for interpreting cortical bone adaptation

2010 ◽  
Vol 144 (1) ◽  
pp. 41-50 ◽  
Author(s):  
John G. Skedros ◽  
Casey J. Kiser ◽  
Shaun D. Mendenhall
Keyword(s):  
Cortical Bone ◽  
Bone Adaptation

scholarly journals Pelvic Construct Prediction of Trabecular and Cortical Bone Structural Architecture

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
Dan T. Zaharie ◽  
Andrew T. M. Phillips
Keyword(s):  
Cortical Bone ◽  
Structural Model ◽  
Thickness Distribution ◽  
Bone Adaptation ◽  
The Body ◽  
Lower Limbs ◽  
Fe Model ◽  
Adaptation Algorithm ◽  
Modeling Framework ◽  
Good Agreement

The pelvic construct is an important part of the body as it facilitates the transfer of upper body weight to the lower limbs and protects a number of organs and vessels in the lower abdomen. In addition, the importance of the pelvis is highlighted by the high mortality rates associated with pelvic trauma. This study presents a mesoscale structural model of the pelvic construct and the joints and ligaments associated with it. Shell elements were used to model cortical bone, while truss elements were used to model trabecular bone and the ligaments and joints. The finite element (FE) model was subjected to an iterative optimization process based on a strain-driven bone adaptation algorithm. The bone model was adapted to a number of common daily living activities (walking, stair ascent, stair descent, sit-to-stand, and stand-to-sit) by applying onto it joint and muscle loads derived using a musculoskeletal modeling framework. The cortical thickness distribution and the trabecular architecture of the adapted model were compared qualitatively with computed tomography (CT) scans and models developed in previous studies, showing good agreement. The sensitivity of the model to changes in material properties of the ligaments and joint cartilage and changes in parameters related to the adaptation algorithm was assessed. Changes to the target strain had the largest effect on predicted total bone volumes. The model showed low sensitivity to changes in all other parameters. The minimum and maximum principal strains predicted by the structural model compared to a continuum CT-derived model in response to a common test loading scenario showed good agreement with correlation coefficients of 0.813 and 0.809, respectively. The developed structural model enables a number of applications such as fracture modeling, design, and additive manufacturing of frangible surrogates.

Loading conditions and cortical bone construction of an artiodactyl calcaneus

1999 ◽  
Vol 202 (22) ◽  
pp. 3239-3254 ◽  
Author(s):  
S.C. Su ◽  
J.G. Skedros ◽  
K.N. Bachus ◽  
R.D. Bloebaum
Keyword(s):  
Cortical Bone ◽  
Compressive Strain ◽  
Mechanical Strain ◽  
Bone Adaptation ◽  
Principal Strain ◽  
Flexor Muscle ◽  
The Mean ◽  
Shear Strains ◽  
Tensile Strains ◽  
Principal Strains

Customary nonuniform distributions of physiological bone strains are thought to evoke heterogeneous material adaptation in diaphyseal cortices of some limb bones. Recent studies of artiodactyl calcanei have suggested that the regional prevalence of specific mechanical strain features such as mode and magnitude correlate with specific variations in cortical bone ultrastructure, microstructure and mineralization. These data are also consistent with predictions of current algorithms of mechanically induced bone adaptation. However, detailed characterization of the customary functional strain environment of these bones is needed to understand better the mechanisms of these adaptations. An in vitro loading method and rosette strain gauges were used to record principal strains, maximum shear strains and principal strain angles at multiple locations on ten calcanei of adult male mule deer (Odocoileus hemionus hemionus). Each hind limb was fixed in an apparatus to mimic the mid-support phase of the gait and loaded via the Achilles tendon over a broad range of functional loads (0 to 2943 N). Strains were recorded on the craniolateral, craniomedial, caudal, medial and lateral cortices at mid-diaphysis. Loading variations included the progressive elimination of the ligament and tendon along the caudal calcaneus. The results showed that the cranial cortex experiences longitudinal compressive strains that are nearly equal to the principal minimum strains and that the caudal cortex receives longitudinal tensile strains that are nearly equal to the principal maximum strains. With a 981 N load, the mean principal compressive strain on the cranial cortex was −636+/−344 micro(ε) (mean +/− s.d., N=9) and the mean principal tensile strain on the caudal cortex was 1112+/−68 micro;(ε)x (N=9). In contrast to the cranial and caudal cortices, principal strains in the medial and lateral cortices displayed relatively large deviations from the longitudinal axis (medial, 24 degrees cranial; lateral, 27 degrees caudal). Although shear strains predominated at all gauge sites, variations in maximum shear strains showed no apparent regional pattern or consistent regional predominance. The plantar ligament and tendon of the superficial digital flexor muscle were shown to have important load-sharing functions. These results demonstrate that the functionally loaded artiodactyl calcaneus generally behaves like a cantilevered beam with longitudinal compression and tension strains predominating in opposing cranial and caudal cortices, respectively. Differences in osteon remodeling rates, osteon morphology and mineral content reported previously between the cranial and caudal cortices correlate, in part, with the magnitudes of the principal compressive and tensile strains, respectively. However, material differences that distinguish the medial and lateral cortices from the cranial and caudal cortices could not be primarily attributed to locally increased shear strains as previously suggested. Variations in osteon and/or collagen fiber orientation may correlate more strongly with principal strain direction.

scholarly journals Cortical bone adaptation to a moderate level of mechanical loading in male Sost deficient mice

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Haisheng Yang ◽  
Alexander Büttner ◽  
Laia Albiol ◽  
Catherine Julien ◽  
Tobias Thiele ◽  
...  
Keyword(s):  
Physical Activity ◽  
Bone Formation ◽  
Bone Mass ◽  
Cortical Bone ◽  
Bone Adaptation ◽  
Moderate Level ◽  
Skeletal Maturation ◽  
Male Mice ◽  
Males And Females

AbstractLoss-of-function mutations in the Sost gene lead to high bone mass phenotypes. Pharmacological inhibition of Sost/sclerostin provides a new drug strategy for treating osteoporosis. Questions remain as to how physical activity may affect bone mass under sclerostin inhibition and if that effect differs between males and females. We previously observed in female Sost knockout (KO) mice an enhanced cortical bone formation response to a moderate level of applied loading (900 με at the tibial midshaft). The purpose of the present study was to examine cortical bone adaptation to the same strain level applied to male Sost KO mice. Strain-matched in vivo compressive loading was applied to the tibiae of 10-, 26- and 52-week-old male Sost KO and littermate control (LC) mice. The effect of tibial loading on bone (re)modeling was measured by microCT, 3D time-lapse in vivo morphometry, 2D histomorphometry and gene expression analyses. As expected, Sost deficiency led to high cortical bone mass in 10- and 26-week-old male mice as a result of increased bone formation. However, the enhanced bone formation associated with Sost deficiency did not appear to diminish with skeletal maturation. An increase in bone resorption was observed with skeletal maturation in male LC and Sost KO mice. Two weeks of in vivo loading (900 με at the tibial midshaft) induced only a mild anabolic response in 10- and 26-week-old male mice, independent of Sost deficiency. A decrease in the Wnt inhibitor Dkk1 expression was observed 3 h after loading in 52-week-old Sost KO and LC mice, and an increase in Lef1 expression was observed 8 h after loading in 10-week-old Sost KO mice. The current results suggest that long-term inhibition of sclerostin in male mice does not influence the adaptive response of cortical bone to moderate levels of loading. In contrast with our previous strain-matched study in females showing enhanced bone responses with Sost ablation, these results in males indicate that the influence of Sost deficiency on the cortical bone formation response to a moderate level of loading differs between males and females. Clinical studies examining antibodies to inhibit sclerostin may need to consider that the efficacy of additional physical activity regimens may be sex dependent.

Mid-term results of anatomical total shoulder arthroplasty for primary osteoarthritis using a short-stemmed cementless humeral component

2018 ◽  
Vol 100-B (5) ◽  
pp. 603-609 ◽  
Author(s):  
M. Schnetzke ◽  
S. Rick ◽  
P. Raiss ◽  
G. Walch ◽  
M. Loew
Keyword(s):  
Cortical Bone ◽  
Shoulder Arthroplasty ◽  
Total Shoulder Arthroplasty ◽  
Bone Adaptation ◽  
Filling Ratio ◽  
Short Stem ◽  
Primary Osteoarthritis ◽  
Humeral Component ◽  
High Bone

Aims The aim of this study was to evaluate the clinical and radiological outcome of using an anatomical short-stem shoulder prosthesis to treat primary osteoarthritis of the glenohumeral joint. Patients and Methods A total of 66 patients (67 shoulders) with a mean age of 76 years (63 to 92) were available for clinical and radiological follow-up at two different timepoints (T1, mean 2.6 years, sd 0.5; T2, mean 5.3 years, sd 0.7). Postoperative radiographs were analyzed for stem angle, cortical contact, and filling ratio of the stem. Follow-up radiographs were analyzed for timing and location of bone adaptation (cortical bone narrowing, osteopenia, spot welds, and condensation lines). The bone adaptation was classified as low (between zero and three features of bone remodelling around the humeral stem) or high (four or more features). Results The mean Constant score improved significantly from 28.5 (sd 11.6) preoperatively to 75.5 (sd 8.5) at T1 (p < 0.001) and remained stable over time (T2: 76.6, sd 10.2). No stem loosening was seen. High bone adaptation was present in 42% of shoulders at T1, with a slight decrease to 37% at T2. Cortical bone narrowing and osteopenia in the region of the calcar decreased from 76% to 66% between T1 and T2. Patients with high bone adaptation had a significantly higher mean filling ratio of the stem at the metaphysis (0.60, sd 0.05 vs 0.55, sd 0.06; p = 0.003) and at the diaphysis (0.65 sd 0.05 vs 0.60 sd 0.05; p = 0.007). Cortical contact of the stem was also associated with high bone adaptation (14/25 shoulders, p = 0.001). The clinical outcome was not influenced by the radiological changes. Conclusion Total shoulder arthroplasty using a short-stem humeral component resulted in good clinical outcomes with no evidence of loosening. However, approximately 40% of the shoulders developed substantial bone loss in the proximal humerus at between four and seven years of follow-up. Cite this article: Bone Joint J 2018;100-B:603–9.

scholarly journals Predicting cortical bone adaptation to axial loading in the mouse tibia

2015 ◽  
Vol 12 (110) ◽  
pp. 20150590 ◽  
Author(s):  
A. F. Pereira ◽  
B. Javaheri ◽  
A. A. Pitsillides ◽  
S. J. Shefelbine
Keyword(s):  
Cortical Bone ◽  
Computational Models ◽  
Mechanical Load ◽  
Fluid Velocity ◽  
Structural Response ◽  
Axial Loading ◽  
Mechanical Stimulus ◽  
Bone Adaptation ◽  
Mouse Tibia ◽  
Efficient Loading

The development of predictive mathematical models can contribute to a deeper understanding of the specific stages of bone mechanobiology and the process by which bone adapts to mechanical forces. The objective of this work was to predict, with spatial accuracy, cortical bone adaptation to mechanical load, in order to better understand the mechanical cues that might be driving adaptation. The axial tibial loading model was used to trigger cortical bone adaptation in C57BL/6 mice and provide relevant biological and biomechanical information. A method for mapping cortical thickness in the mouse tibia diaphysis was developed, allowing for a thorough spatial description of where bone adaptation occurs. Poroelastic finite-element (FE) models were used to determine the structural response of the tibia upon axial loading and interstitial fluid velocity as the mechanical stimulus. FE models were coupled with mechanobiological governing equations, which accounted for non-static loads and assumed that bone responds instantly to local mechanical cues in an on–off manner. The presented formulation was able to simulate the areas of adaptation and accurately reproduce the distributions of cortical thickening observed in the experimental data with a statistically significant positive correlation (Kendall's τ rank coefficient τ = 0.51, p < 0.001). This work demonstrates that computational models can spatially predict cortical bone mechanoadaptation to a time variant stimulus. Such models could be used in the design of more efficient loading protocols and drug therapies that target the relevant physiological mechanisms.

DEVELOPMENT OF AN ALGORITHM FOR THE COMPUTATION OF CORTICAL BONE ADAPTATION

2012 ◽  
Vol 45 ◽  
pp. S113
Author(s):  
Andre Pereira ◽  
Andrew Pitsillides ◽  
Sandra Shefelbine
Keyword(s):  
Cortical Bone ◽  
Bone Adaptation

373 CORTICAL BONE ADAPTATION TO WEIGHT BEARING EXERCISE

1990 ◽  
Vol 22 (2) ◽  
pp. S63
Author(s):  
D. M. Raab ◽  
T. D. Crenshaw ◽  
E. L. Smith
Keyword(s):  
Cortical Bone ◽  
Weight Bearing ◽  
Bone Adaptation

scholarly journals Predicting cortical bone adaptation to axial loading in the mouse tibia

2015 ◽  
Author(s):  
Andre F Pereira ◽  
Behzad Javaheri ◽  
Andrew Pitsillides ◽  
Sandra Shefelbine
Keyword(s):  
Cortical Bone ◽  
Computational Models ◽  
Mechanical Load ◽  
Fluid Velocity ◽  
Structural Response ◽  
Axial Loading ◽  
Mechanical Stimulus ◽  
Bone Adaptation ◽  
Mouse Tibia ◽  
Efficient Loading

The development of predictive mathematical models can contribute to a deeper understanding of the specific stages of bone mechanobiology and the process by which bone adapts to mechanical forces. The objective of this work was to predict, with spatial accuracy, cortical bone adaptation to mechanical load, in order to better understand the mechanical cues that might be driving adaptation. The axial tibial loading model was used to trigger cortical bone adaptation in C57BL/6 mice and provide relevant biological and biomechanical information. A method for mapping cortical thickness in the mouse tibia diaphysis was developed, allowing for a thorough spatial description of where bone adaptation occurs. Poroelastic finite-element (FE) models were used to determine the structural response of the tibia upon axial loading and interstitial fluid velocity as the mechanical stimulus. FE models were coupled with mechanobiological governing equations, which accounted for non-static loads and assumed that bone responds instantly to local mechanical cues in an on-off manner. The presented formulation was able to simulate the areas of adaptation and accurately reproduce the distributions of cortical thickening observed in the experimental data with a statistically significant positive correlation (Kendall's tau rank coefficient \(\tau = 0.51\), \(p<0.001\)). This work demonstrates that computational models can spatially predict cortical bone mechanoadaptation to time variant stimulus. Such models could be used in the design of more efficient loading protocols and drugs therapies that target the relevant physiological mechanisms.

scholarly journals Sost deficiency leads to reduced mechanical strains at the tibia midshaft in strain-matched in vivo loading experiments in mice

2018 ◽  
Vol 15 (141) ◽  
pp. 20180012 ◽  
Author(s):  
Laia Albiol ◽  
Myriam Cilla ◽  
David Pflanz ◽  
Ina Kramer ◽  
Michaela Kneissel ◽  
...  
Keyword(s):  
Bone Formation ◽  
Cortical Bone ◽  
Neutralizing Antibodies ◽  
Bone Geometry ◽  
Bone Adaptation ◽  
Mechanical Stimuli ◽  
Mineral Density ◽  
Littermate Control ◽  
Mechanical Environment

Sclerostin, a product of the Sost gene, is a Wnt-inhibitor and thus negatively regulates bone accrual. Canonical Wnt/β-catenin signalling is also known to be activated in mechanotransduction. Sclerostin neutralizing antibodies are being tested in ongoing clinical trials to target osteoporosis and osteogenesis imperfecta but their interaction with mechanical stimuli on bone formation remains unclear. Sost knockout (KO) mice were examined to gain insight into how long-term Sost deficiency alters the local mechanical environment within the bone. This knowledge is crucial as the strain environment regulates bone adaptation. We characterized the bone geometry at the tibial midshaft of young and adult Sost KO and age-matched littermate control (LC) mice using microcomputed tomography imaging. The cortical area and the minimal and maximal moment of inertia were higher in Sost KO than in LC mice, whereas no difference was detected in either the anterior–posterior or medio-lateral bone curvature. Differences observed between age-matched genotypes were greater in adult mice. We analysed the local mechanical environment in the bone using finite-element models (FEMs), which showed that strains in the tibiae of Sost KO mice are lower than in age-matched LC mice at the diaphyseal midshaft, a region commonly used to assess cortical bone formation and resorption. Our FEMs also suggested that tissue mineral density is only a minor contributor to the strain distribution in tibial cortical bone from Sost KO mice compared to bone geometry. Furthermore, they indicated that although strain gauging experiments matched strains at the gauge site, strains along the tibial length were not comparable between age-matched Sost KO and LC mice or between young and adult animals within the same genotype.

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