The mechanical properties of bone
01 Nov 1970-Clinical Orthopaedics and Related Research (Clin Orthop Relat Res)-Vol. 73, Iss: 6, pp 209-231
TL;DR: BONE is the material with which the orthopaedic surgeon deals and some knowledge of its mechanical properties is of importance for an understanding of the mechanism and management of fractures, as well as the design of prosthetic or orthotic appliances and protective gear.
Abstract: 2 Department of Anatomy and Highway Safety Research Institute, The University of Michigan, Ann Arbor, Mich. 48104. BONE is the material with which the orthopaedic surgeon deals. Consequently, some knowledge of its mechanical properties is of importance for an understanding of the mechanism and management of fractures, as well as the design of prosthetic or orthotic appliances and protective gear, e.g., crash helmets. The behavior of a body under a load or force is a function not only of the form and structure of the body, but also of the mechanical properties of the material composing the body. For example, a steel beam will support a higher load before breaking and will behave differently under loading than will an oak beam of exactly the same shape and dimensions because of differences in the mechanical properties and structure of steel and of wood.
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TL;DR: The results of this previous study are applied to cancellous bone in an attempt to further understand its mechanical behaviour and the results agree reasonably well with experimental data available in the literature.
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TL;DR: A new process chain for custom-made three-dimensional (3D) porous ceramic scaffolds for bone replacement with fully interconnected channel network for the repair of osseous defects from trauma or disease is reported.
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Cites background from "The mechanical properties of bone"
...The compression strength of the test parts ranges between that of human spongiosa and that of cortical bone.(21)...
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TL;DR: Results indicate that this sophisticated technique, which is still early in its development, can achieve precision comparable to that of densitometry and can predict femoral fracture load to within -40% to +60% with 95% confidence.
635 citations
Cites background from "The mechanical properties of bone"
...…et al., 1991; Keyak et al., 1994; Reilly and Burstein, 1975; Van Buskirk and Ashman, 1981) and accounting for the fact that bone material strength is about 30% lower in tension than in compression (Currey, 1970; Keaveny et al., 1994a,b; Reilly and Burstein, 1975) may improve FE model predictions....
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..., 1994; Reilly and Burstein, 1975; Van Buskirk and Ashman, 1981) and accounting for the fact that bone material strength is about 30% lower in tension than in compression (Currey, 1970; Keaveny et al., 1994a,b; Reilly and Burstein, 1975) may improve FE model predictions....
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TL;DR: The menisci provide surface compliance and serve to transmit stresses across the wider areas to the periphery, and, therefore, help to avoid stress concentration both in the articular cartilage and in the subchondral bone, especially under high loads over 1,000 N.
Abstract: The load-bearing mode of the knee joint and the load-carrying capacity of the menisci were investigated by a load-deflection and load-contact study using stresses of as much as 3 times body weight on 14 freshly amputated knee specimens. A flection angle of 0 degrees was used. The average deflection and the average size of the contact area of the intact knees were 1.04 x 10(-1) cm and 14.1 cm2 respectively when the knees were loaded to 1,500 N. The elastic modulus of the entire joint was 2.7 x 10(2) MPa over the load of 1,500 N. At first, the knee joint was not congruous at a low load under about 500 N; the joint contacts both menisci in conjunction with some part of the exposed cartilage. However, the joint became markedly congruous at higher loads, around 1,000 N. The joint was in contact with the menisci and the exposed cartilage, and as more load was applied, the areas of contact widened to the peripheral areas of both the compartments. After menisci were removed, the deflection increased. The size of the contact areas decreased significantly by a third to a half. Consequently, the average stress increased 2 to 3 times that of the intact knee. The elastic modulus was increased over 2 fold after menisci were removed. The results of the energy study indicate that the menisci gave more elastic stability to the joint. After the menisci were removed, more energy was dissipated during cyclic loading. Thus, the menisci provide surface compliance and serve to transmit stresses across the wider areas to the periphery, and, therefore, help to avoid stress concentration both in the articular cartilage and in the subchondral bone, especially under high loads over 1,000 N.
572 citations
References
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"The mechanical properties of bone" refers background in this paper
...Compression fractures are quite common in the bodies of the vertebrae, especially those in the lumbar region, and in the calcaneus, the most frequently fractured of the tarsal bones (12)....
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TL;DR: Comparisons on all the long bones of the inferior extremity of three adult male cadavers revealed that the tibia had the greatest average tensile strength and the fibula the greatest percentage elongation under tension, and the femur was the weakest in these respects.
Abstract: 1.1. The average ultimate tensile strength (Ib./in. 2 ) and percentage elongation under tension were determined for 242 specimens of compact bone from the femurs of seven white, adult male cadavers whose age and cause of death were known. 2.2. All specimens were of a standardized size and were tested by approved engineering technics which are described. Half of the specimens were air dried at room temperature and tested dry while the other half were placed in a physiologic saline solution and tested wet. 3.3. Drying the specimens increased their average tensile strength (Ib./in. 2 ) but reduced their percentage elongation under tension. The percentage elongation under tension is a good index of the energy (in. Ib./in. 3 ) absorbed by the specimen up to the time of fracture. 4.4. The samples tested wet had a greater percentage elongation under tension, and hence greater energy-absorbing capacity, than did the dry samples. This is also evident from the shape of the stress-strain curve which is a straight line to fracture for the dry samples but a curve for the wet specimens. 5.5. The specimens from the middle third of the femoral shaft had the greatest average tensile strength and energy-absorbing capacity, as indicated by their percentage elongation under tension. 6.6. The age of the individual seemed to have little influence on the tensile strength and energy-absorbing capacity of the femur. 7.7. Similar comparative studies on all the long bones of the inferior extremity of three adult male cadavers revealed that the tibia had the greatest average tensile strength (Ib./in. 2 ) and the fibula the greatest percentage elongation under tension. The femur was the weakest in these respects. 8.8. As in the femur the middle third of the tibia and fibula had the greatest average tensile strength (Ib./in. 2 ). The middle third of the tibia also had the greatest percentage elongation but in the fibula, and also the femurs of these individuals, the proximal third of the bone had the greatest elongation. These comparative results should be considered as tentative but also indicative of a trend. 9.9. The values for the physical properties of the wet-tested specimens probably more nearly approximate similar properties in living bone than do those of dry-tested specimens. 10.10. The significance and implications of the tests are discussed.
81 citations
TL;DR: The "stresscoat" deformation patterns obtained in the fractured bones clearly demonstrated that, with the possible exception of the abduction type, each of the various kinds of fractures arose from the failure of the bone as the result of the tensile strain.
Abstract: 1. Static and dynamic loading tests were made on fifty femora from dissecting-room, adult cadavera of known sex, age, and race. The cause of death was also known, and no grossly pathological bones were used. All bones were not loaded to failure.
2. Most of the bones were "stresscoated" so that the tensile deformation pattern produced during the tests was obtained.
3. In each test the magnitude, point of application, direction, and type of force, as well as the orientation of the bone, were the controlled variables. These factors, however, were not uniform in all tests.
4. Vertical transverse fractures of the femoral neck were produced by static vertical loading of the fensoral head. No torsional force was involved.
5. Static vertical loading of the femur clearly demonstrated its behavior as an elastic body.
6. Subcapital, intertrochanteric, abduction, horizontal, and oblique fractures of the neck were obtained by static and dynamic loading of the greater trochanter, with the bone in slightly different positions. No torsion was involved in the fracture mechanism.
7. Spiral fractures of the shaft were produced by static torsion loading.
8. Transverse fractures of the shaft were produced by cross-bending loads.
9. The "stresscoat" deformation patterns obtained in the fractured bones clearly demonstrated that, with the possible exception of the abduction type, each of the various kinds of fractures arose from the failure of the bone as the result of the tensile strain.
10. Contrary to a rather general belief, transverse fractures of the femoral neck are not produced by torsional forces. There is no mechanism in the living body that can produce torsional strain in the femoral neck.
11. Shearing force is also not involved in the fracture mechanism although, depending upon the obliquity of the fracture line, it can be a serious factor in the treatment of such fractures.
12. Spiral fractures of the shaft are merely other examples of the failure of the bone as the result of the tensile strain. They do not arise from shearing stress.
75 citations
"The mechanical properties of bone" refers background in this paper
...Physick (19) and more recently suggested by Evans, Pedersen, and Lissner (10)....
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...Evans, F. G., H. E. Pedersen, and H. R. Lissner, The role of tensile stress in the mechanism of femoral fractures, J. Bone Joint Surg., 33A: 485-501, 1951....
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...9), its foam-like structure makes it a good energy-absorbing material, as demonstrated experimentally more than a century ago by Dr. Physick (19) and more recently suggested by Evans, Pedersen, and Lissner (10)....
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...Lissner, H. R., and F. G. Evans, Engineering aspects of fractures, Clin....
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...The capacity of bone to absorb energy is one of its important mechanical properties as far as fracture mechanics is concerned because, as pointed out by Lissner and Evans (16), all physical injuries arise from the absorption of energy....
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