Stress and strain distribution within the intact femur: compression or bending?

Taylor, Mark; Tanner, K. E.; Freeman, Michael; Yettram, A.L.

doi:10.1016/1350-4533(95)00031-3

Cited by 216 publications

(164 citation statements)

References 15 publications

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“…Opinions differ in the literature [1,21] on the question of whether long bones are predominantly loaded in bending or in compression. In any case, the precise stress analysis of a bone is difficult owing to many uncertainties.…”

Section: Stress Analysis Of the Human Tibiamentioning

confidence: 98%

The prediction of stress fractures using a ‘stressed volume’ concept

Taylor

Kuiper

2001

Journal Orthopaedic Research

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This paper addresses an anomaly which exists in the current literature regarding stress fractures. Analysis of the data on fatigue strength of bone samples in vitro would conclude that these fractures should never occur at the strain levels known to occur in vivo. This anomaly can be resolved by including in the analysis the effect of stressed volume, whereby larger volumes of material are expected to have worse fatigue properties. A Weibull analysis was used to predict the probability of failure, pt; this was an upperbound prediction because it did not include the effects of remodelling and adaptation. Combining this analysis with a finite element model of the human tibia, we predicted a Pf value of 21% after five weeks of strenuous exercise, which is comparable with reported incidences in military personnel. The high incidence of stress fractures in the cannon bone of racehorses could also be predicted (Pr = 62'%, compared to 70% experimentally). The approach can be used to investigate the effect of variables in the exercise regime such as the distance run per day and the use of improved footwear. It can also predict the increased risk of stress fractures in elderly people. The results suggest certain simple rules which may be of clinical value in designing exercise regimes and in understanding the risk factors for this type of injury.

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Section: Stress Analysis Of the Human Tibiamentioning

confidence: 98%

The prediction of stress fractures using a ‘stressed volume’ concept

Taylor

Kuiper

2001

Journal Orthopaedic Research

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“…If the recorded strain values are artificially increased, it would directly affect the results predicted by the final femur FE model. Not only did the joint constrained model outperform the other two, the femoral deflection and joint reaction forces also agreed well with published experimental data (Taylor et al, 1996). Based upon the close physiologic agreement of the deflection, it was assumed that the joint constrained model also produced a physiologic strain field for the femur.…”

Section: Joint Bcsupporting

confidence: 71%

Development of a Subject Specific Finite Element Model Used to Predict the Effects of a Single Leg Extension Exercise

Gleeson¹

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The study presented attempts to prove the concept that mechanical changes in the structure of a bone can be predicted for a specific exercise by a subject specific model created from CT data, MRI data, EMG data, and a physiologic FE model. Previous work generated a subject specific FE model of a femur via CT and MRI data as well as created a set of subject specific biomechanical muscle forces that are required to perform a single leg extension exercise. The FE model and muscle forces were implemented into a single leg extension FE code (ABAQUS) along with a specialized bone remodeling UMAT. The UMAT updated the mechanical properties of the femur via a damage-repair bone remodeling algorithm. The single leg extension FE code was verified by applying walking loads to the femur and allowing the system to equilibrate. The results were used to apply the appropriate walking loads to the final FE simulation for the single leg extension exercise. The final FE simulation included applying the single leg extension loads over a one year period and plotting the change in porosity at various regions of the femoral neck. Although only two regions were found to generate valid results, the data seemed counterintuitive to Wolff's Law which states that bone adaptation is promoted when the material is stressed. The model was successful in creating a subject specific model that is capable of predicting changes in the mechanical properties of bone. However, in order to generate valid FE model results, further understanding of the bone remodeling process and application via a FE model is required.

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“…O aumento do ângulo de inclinação altera o ângulo da força total sobre a articulação coxofemoral, modificando o seu valor normal de 69° para até 80° (Weigel e Wasserman, 1992). O ângulo da força total sobre a articulação exerce grande influência na distribuição das forças sobre o fêmur, podendo ocasionar alterações na espessura cortical óssea (Taylor et al, 1996).…”

Section: Resultsunclassified

Associação entre o ângulo de Norberg, o percentual de cobertura da cabeça femoral, o índice cortical e o ângulo de inclinação em cães com displasia coxofemoral

Vieira¹,

Torres²,

Barros³

et al. 2010

Arq. Bras. Med. Vet. Zootec.

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 RESUMOForam avaliadas 386 radiografias da articulação coxofemoral, sendo 220 de cães da raça Pastor Alemão, 112 machos e 108 fêmeas, e 166 da raça Labrador Retriever, 69 machos e 97 fêmeas. As radiografias foram classificadas segundo o grau de displasia coxofemoral (DCF), e foram mensurados o ângulo de inclinação, o ângulo de Norberg, o índice cortical e o percentual de cobertura da cabeça femoral de ambos os lados. As variáveis foram associadas mediante análise estatística multivariada de componentes principais. As variáveis índice cortical e ângulo de inclinação foram inversamente associadas. A raça Pastor Alemão apresentou valores de índice cortical e graus de DCF mais baixos em relação à raça Labrador Retriever. Maior ângulo de inclinação foi associado a menor ângulo de Norberg e menor percentual de cobertura. Animais mais velhos apresentaram menor ângulo de Norberg, menor porcentagem de cobertura e maior grau de DCF. Nas fêmeas, foram observados menor porcentagem de cobertura, menor ângulo de Norberg e maior grau de DCF. Pode-se concluir que o ângulo de inclinação e o índice cortical não demonstraram associação com a DCF.Palavras-chave: cão, displasia coxofemoral, ângulo de Norberg, índice cortical, ângulo de inclinação, percentual de cobertura ABSTRACT A total of 386 radiographs of the pelvis were evaluated, being 220 of German Shepherd dogs (112 males and 108 females) and 166 of Labrador Retrievers (69 males and 97 females). The radiographs were degree classified regarding the of hip dysplasia (DHD). The Norberg and inclination angles, the corticomedullary index, and the percentage coverage of the femoral head were measured and associated using multivariate statistical technique (principal component analysis). The cortico-medullary index and the inclination angle were inversely associated. The results indicated that German Shepherd

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Stress and strain distribution within the intact femur: compression or bending?

Cited by 216 publications

References 15 publications

The prediction of stress fractures using a ‘stressed volume’ concept

The prediction of stress fractures using a ‘stressed volume’ concept

Development of a Subject Specific Finite Element Model Used to Predict the Effects of a Single Leg Extension Exercise

Associação entre o ângulo de Norberg, o percentual de cobertura da cabeça femoral, o índice cortical e o ângulo de inclinação em cães com displasia coxofemoral

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