Osteoporosis International

, Volume 5, Issue 4, pp 252–261 | Cite as

Stress distributions within the proximal femur during gait and falls: Implications for osteoporotic fracture

  • J. C. Lotz
  • E. J. Cheal
  • W. C. Hayes
Original Article

Abstract

The rates of fracture at sites with different relative amounts of cortical and trabecular bone (hip, spine, distal radius) have been used to make inferences about the pathomechanics of bone loss and the existence of type I and type II osteoporosis. However, fracture risk is directly related to the ratio of tissue stress to tissue strength, which in turn is dependent not only on tissue composition but also tissue geometry and the direction and magnitude of loading. These three elements determine how the load is distributed within the tissue. As a result, assumptions on the relative structural importance of cortical and trabecular bone, and how these tissues are affected by bone loss, can be inaccurate if based on regional tissue composition and bone density alone. To investigate the structural significance of cortical and trabecular bone in the proximal femur, and how it is affected by bone loss, we determined the stress distributions in a normal and osteoporotic femur resulting from loadings representing: (1) gait; and (2) a fall to the side with impact onto the greater trochanter. A three-dimensional finite element model was generated based on a representative femur selected from a large database of femoral geometries. Stresses were analyzed throughout the femoral neck and intertrochanteric regions. We found that the percentage of total load supported by cortical and trabecular bone was approximately constant for all load cases but differed depending on location. Cortical bone carried 30% of the load at the subcapital region, 50% at the mid-neck, 96% at the base of the neck and 80% at the intertrochanteric region. These values differ from the widely held assumption that cortical bone carries 75% of the load in the femoral neck and 50% of the load at the intertrochanteric region. During gait, the principal stresses were concentrated within the primary compressive system of trabeculae and in the cortical bone of the intertrochanteric region. In contrast, during a fall, the trabecular stresses were concentrated within the primary tensile system of trabeculae with a peak magnitude 4.3 times that present during gait. While the distribution of stress for the osteoporotic femur was similar to the normal, the magnitude of peak stress was increased by between 33% and 45%. These data call into question several assumptions which serve as the basis for theories on the pathomechanics of osteoporosis. In addition, we expect that the insight provided by this analysis will result in the improved development and interpretation of non-invasive techniques for the quantification of in vivo hip fracture risk.

Keywords

Fall Finite element analysis Gait Hip fracture OsteoporosisStress 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    Hayes WC. Biomechanics of cortical and trabecular bone: implications for assessment of fracture risk. In: Mow VC, Hayes WC, editors. Basic orthopaedic biomechanics. New York: Raven Press, 1991.Google Scholar
  2. 2.
    Courtney AC, Wachtel EF, Meyers ER, Hayes WC. Age-related reductions in the strength of the femur treated in a fall-loading configuration. J Bone Joint Surg 1994;55(1):S3–8.Google Scholar
  3. 3.
    Leichter I, Margulies JY, Weinreb A, et al. Mechanical strength of the femoral neck in relation to density and mineral content of bone. In Menczel J, Ropbin GC, Makin M, Steinberg R, editors. Osteoporosis. Israel: Wiley, 1982:166–73.Google Scholar
  4. 4.
    Backman S. The proximal end of the femur. Act Radiol [Suppl] 1957;146:1–166.Google Scholar
  5. 5.
    Hirsch C, Frankel VH. Analysis of forces producing fractures of the proximal end of the femur. J Bone Joint Surg [42B] 1960;42:633–40.Google Scholar
  6. 6.
    Smith L. Hip fracture: the role of muscle contraction or intrinsic forces in the causation of fractures of the femoral neck. J Bone Joint Surg [Am] 1953;35:367–82.PubMedGoogle Scholar
  7. 7.
    Mizrahi J, Margulies JY, Leichter I, Deutsch D. Fracture of the human femoral neck: effect of density of the cancellous core. J Biomed Eng 1984;6:56–62.PubMedGoogle Scholar
  8. 8.
    Williams JF, Svensson NL. An experimental stress analysis of the neck of the femur. Med Biol Eng 1971;9:479–93.PubMedGoogle Scholar
  9. 9.
    Rohlmann A, Mossner U, Bergman G, Kolbel R. Finite-element-analysis and experimental investigation in a femur with hip endoprosthesis. J Biomech 1983;16:727–42.PubMedGoogle Scholar
  10. 10.
    Huiskies R, Janssen JD, Sloof TJ. A detailed comparison of experimental and theoretic stress analyses of a human femur. In: Cowin S, editors. Mechanical properties of bone. New York: American Society of Mechanical Engineers, 1981:211–34.Google Scholar
  11. 11.
    Crowninshield RD, Pederson DR, Brand RA. A measurement of proximal femur strain with total hip arthroplasty. J Biomech Eng 1980;102:230–33.Google Scholar
  12. 12.
    Lotz JC, Hayes WC. Mechanical properties of metaphyseal bone in the proximal femur. J Biomech 1991;24:317–29.PubMedGoogle Scholar
  13. 13.
    Melton LJ, Chao EYS, Lane J. Biomechanical aspects of fractures. In: Riggs BL, and Melton LJ, editors. Osteoporosis: etiology, diagnosis and management. New York: Raven Press, 1988;111–31.Google Scholar
  14. 14.
    Hinton RY, Smith GS. The association of age, race, and sex with the location of proximal femoral fractures in the elderly. J Bone Joint Surg [Am] 1993;75:752–9.PubMedGoogle Scholar
  15. 15.
    Aitken JM. Relevance of osteoporosis in women with fracture of the femoral neck. BMJ 1984;288:597–601.PubMedGoogle Scholar
  16. 16.
    Hedlund R, Ahlbom A, Lindgren U. Hip fracture incidence in Stockholm 1972–1981. Acta Orthop Scand 1985;57:30–4.Google Scholar
  17. 17.
    Melton LJ, Riggs BL. Risk factors for injury after a fall. Symposium on falls in the elderly: biological and behavioral aspects. Clin Geriatr Med 1985;1:25–39.Google Scholar
  18. 18.
    Zetterberg C, Elmerson S, Andersson GBJ. Epidemiology of hip fractures in Goteborg, Sweden, 1940–1983. Clin Orthop 1984;191:43–52PubMedGoogle Scholar
  19. 19.
    Riggs BL, Wahner HW, Seeman E, et al. Changes in bone mineral density of the proximal femur and spine with aging: differences between the postmenopausal and senile osteoporosis syndromes. J Clin Invest 1982;70:716–23.PubMedGoogle Scholar
  20. 20.
    Riggs L, Melton LJ. Evidence for two distinct syndromes of involutional osteoporosis. Am J Med 1983;75:899–902.PubMedGoogle Scholar
  21. 21.
    Ruff CB, Hayes WC. Sex differences in age-related remodeling of the femur and tibia. J Orthop Res 1988;6:886–96.PubMedGoogle Scholar
  22. 22.
    Cheal EJ, Hayes WC, Lee CH, Snyder BD, Miller J. Stress analysis of a condylar knee tibial component: influence of metaphyseal shell properties and cement injection depth. J Orthop Res 1985;3:424–34.PubMedGoogle Scholar
  23. 23.
    Ruff CB, Hayes WC. Cross-sectional geometry of Pecos Pueblo femora and tibiae: a biomechanical investigation. I. Method and general patterns of variation. Am J Phys Anthropol 1983;60:383–400.PubMedGoogle Scholar
  24. 24.
    Ruff CB, Hayes WC. Cross-sectional geometry of Pecos Pueblo femora and tibiae: a biomechanical investigation. II. Sex, age and size differences. Am J Phys Anthropol 1983;60:383–400.PubMedGoogle Scholar
  25. 25.
    Lotz JC, Hayes WC. The use of quantitative computed tomography to estimate risk of fracture of the hip from falls. J Bone Joint Surg [Am] 1990;72:689–700.PubMedGoogle Scholar
  26. 26.
    Murray RP, Hayes WC, Edwards WT, Harry JD. Mechnical properties of the subchondral plate and the metaphyseal shell. Thirtieth annual meeting of the Orthopaedic Research Society, 1984;9:197.Google Scholar
  27. 27.
    Brown TD, Ferguson AB. Mechanical property distributions in the cancellous bone of the human proximal femur. Acta Orthop Scand 1980;51:429–37.PubMedGoogle Scholar
  28. 28.
    Martens M, van Audekercke R, Delport P, De Meester P, Mulier JC. The mechanical characteristics of cancellous bone at the upper femoral region. J Biomech 1983;16:971–83.PubMedGoogle Scholar
  29. 29.
    Dickenson RP, Hutton WC, Stott JRR. The mechanical properties of bone in osteoporosis. J Bone Joint Surg [Br] 1981;63:233–8.Google Scholar
  30. 30.
    Rice JC, Cowin SC, Bowman JA. On the dependence of the elasticity and strength of cancellous bone on apparent density. J Biomech 1988;21:155–68.PubMedGoogle Scholar
  31. 31.
    Mazess RB. On aging bone loss. Clin Orthop 1982;165:239–52.PubMedGoogle Scholar
  32. 32.
    Williams J, Lissner HR. Biomechanics of human motion. Philadelphia: WB Saunders: 1962.Google Scholar
  33. 33.
    Patriarco AG, Mann RW, Simon SR, Mansour JM. An evaluation of the approaches of optimization models in the prediction of muscle forces during human gait. J Biomech 1981;14:513–25.PubMedGoogle Scholar
  34. 34.
    Crowninshield RD. Use of optimization techniques to predict muscle forces. J Biomech Eng 1978;100:88.Google Scholar
  35. 35.
    Robinovitch SN, Hayes WC, McMahon TA. Prediction of femoral impact forces in falls on the hip. J Biomech Eng 1991;113:366–74.PubMedGoogle Scholar
  36. 36.
    Lotz JC, Cheal EJ, Hayes WC. Fracture prediction for the proximal femur using finite element models. I. Linear analysis. J Biomech Eng 1991;113:353–60.PubMedGoogle Scholar
  37. 37.
    Lotz JC, Cheal EJ, Hayes WC. Fracture prediction for the proximal femur using finite element models. II. Nonlinear analysis. J Biomech Eng 1991;113:361–5.PubMedGoogle Scholar
  38. 38.
    Lotz JC, Gerhart TN, Haynes WC. Mechanical properties of trabecular bone from the proximal femur: a quantitative CT study. J Comput Assist Tomogr 1990;14:107–14.PubMedGoogle Scholar
  39. 39.
    Wolff J. Das Gesetz der Transformation der Knochen. Berlin: Hirschwald, 1892.Google Scholar
  40. 40.
    Scheck M. The significance of posterior comminution in femoral neck fractures. Clin Orthop 1980;152:138–42.PubMedGoogle Scholar
  41. 41.
    Klenerman L, Marcuson RW. Intracapsular fractures of the neck of the femur. J Bone Joint Surg [Br] 1970;52:514–7.Google Scholar
  42. 42.
    Melton LJ, Riggs BL. Epidemiology of age-related fractures. In: Avioli LV, editor. The osteoporotic syndrome: detection, prevention, and treatment. Orlando: Grune & Stratton, 1987:1–30.Google Scholar
  43. 43.
    Alffram PA. An epidemiologic study of cervical and trochanteric fracture of the femur in an urban population. Acta Orthop Scand Suppl 1964;65:1–109.Google Scholar
  44. 44.
    Greenspan SL, Myers ER, Maitland LA, Resnick NM, Hayes WC. Fall severity and bone mineral density as risk factors for hip fracture in ambulatory elderly. JAMA 1994;271:128–33.PubMedGoogle Scholar
  45. 45.
    Hayes WC, Myers ER, Morris JN, Gerhart TN, Yett HS, Lipsitz LA. Impact near the hip dominates fracture risk in elderly nursing home residents who fall. Calcif Tissue Int 1993;52:192–8.PubMedGoogle Scholar
  46. 46.
    Keyak JD, Fourkas MG, Meager JM, Skinner HB. Validation of an automated method of three-dimensional finite element modelling of bone. J Biomed Eng 1993;15:505–9.PubMedGoogle Scholar
  47. 47.
    Hayes WC. Biomechanics of falls and hip fracture in the elderly. American Academy of Orthopaedic Surgeons Workshops on Prevention of Falls and Hip Fractures in the Elderly, Chicago, Illinois, 1993.Google Scholar
  48. 48.
    Carter DR, Hayes WC. The compressive behavior of bones as a two-phase porous structure. J Bone Joint Surg [59A] 1977;59:954–62.PubMedGoogle Scholar
  49. 49.
    Mosekilde L, Mosekilde L. Normal vertebral body size and compressive strength: relations to age and to vertebral and iliac trabecular bone compressive strength. Bone 1986;7:207–12.PubMedGoogle Scholar
  50. 50.
    Parfitt AM. Bone age, mineral density, and fatigue damage. Calcif Tissue Int 1993;53:S82–5.PubMedGoogle Scholar
  51. 51.
    Schnitzler CM. Bone quality: a determinant for certain risk factors for bone fragility. Calcif Tissue Int 1993;53:S27–31.PubMedGoogle Scholar
  52. 52.
    Guo XE, McMahon TA, Keaveny TM, Hayes WC, Gibson LJ. Finite element modeling of damage accumulation in trabecular bone under cyclic loading. J Biomech 1994;27:145–55.PubMedGoogle Scholar

Copyright information

© European Foundation for Osteoporosis 1995

Authors and Affiliations

  • J. C. Lotz
    • 1
  • E. J. Cheal
    • 1
  • W. C. Hayes
    • 1
  1. 1.Orthopedic Biomechanics Laboratory, Department of Orthopedic SurgeryBeth Israel HospitalBostonUSA

Personalised recommendations