Fractures in OP

Fractures are one of the most serious clinical signs of osteoporosis as well as the clinical sequelae which has the most impact on a patient’s function, psychological well-being and life.  As mentioned earlier 80% of hip fractures are osteoporosis-related. Hip fractures result in death in up to 20% of cases, and disability in 50% of those who survive.

An osteoporotic fracture is often referred to as a “fragility” fracture or “low-trauma” fracture. In general both of these are referring to a fracture resulting from a fall from standing height or equivalent degree of trauma. This can include: slipping on ice, tripping and falling, lifting something, coughing or sneezing. Often the term fragility fracture is interpreted to infer that the bones are particularly thin already, but a fracture resulting from a standing height fall can still cause a fracture in those who are just starting to lose bone density (osteopenic), so there seems to be a movement towards using the terminology ‘low-trauma’ fracture instead.

Usual sites of osteoporotic fractures include: ribs, wrist, spine, hip, and humerus. The reported lifetime fragility fracture risk is 1:2 for women; 1:8 for men. (Hover over red markers to identify.)

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Wrist

Ribs

Spine

Humerus

Hip

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Focus on hip & vertebral fractures

It has been reported that over 90% of hip fractures in the elderly are as a result of a fall but interestingly only 5% of all falls actually result in a hip fracture (Grisso, 1996). This suggests that it is not just the fall which causes a hip fracture and that there must be a fall characteristic, like point of contact or leg orientation which is the more important determinant of a fracture (Silva, 2007).   Researchers have demonstrated that those people who fall to the side (onto the greater trochanter, for example) are 6-20 times more likely to sustain a fracture compared to other fallers (Greenspan, 1994; Hayes, 1993). Other research using computer modeling has concluded that falling on the hip laterally with the leg internally rotated results in a high possibility of fracture as the femoral neck is weakest to a postero-lateral blow (Keyak, 2001).

While hip fractures are clearly most common as a result of falls, vertebral fractures are not as likely to arise from a fall, in fact only 1/3 result from falling (Cooper, 1992). Vertebral fractures can arise from accidents or lifting heavy objects but nearly 60% are spontaneous and not related to a single incident or event. Thus vertebral fractures may occur incrementally and not catastrophically.

Osteoporotic vertebral fractures are nearly always end-plate fractures and thus results in a crush of the vertebral body (centrally or uniformly) or an anterior wedging of the vertebral body. The most clinically obvious result of vertebral fractures is a notable thoracic kyphosis or loss of height.

Interestingly, hip and vertebral fractures are related. Prevalent vertebral fractures significantly increase the risk of future hip fracture. Several studies, have demonstrated a 2-3 fold increase over a 10 year period in the relative risk of hip fracture for those osteoporosis patients with a prevalent vertebral fracture versus those with no previous vertebral fracture (Black, 1999; Gunnes, 1998; Lauritzen, 1993; Melton, 1999)

Grisso, J. A., & Ness, R. B. (1996). Update in women's health. Ann Intern Med, 125(3), 213-220.

Silva, M. J., & Touhey, D. C. (2007). Bone formation after damaging in vivo fatigue loading results in recovery of whole-bone monotonic strength and increased fatigue life. J Orthop Res, 25(2), 252- 261.

Greenspan, S. L., Myers, E. R., Maitland, L. A., Resnick, N. M., & Hayes, W. C. (1994). Fall severity and bone mineral density as risk factors for hip fracture in ambulatory elderly. JAMA, 271(2), 128- 133.

Hayes, W. C., Myers, E. R., Morris, J. N., Gerhart, T. N., Yett, H. S., & Lipsitz, L. A. (1993). Impact near the hip dominates fracture risk in elderly nursing home residents who fall. Calcif Tissue Int, 52(3), 192-198.

Keyak, J. H., Rossi, S. A., Jones, K. A., Les, C. M., & Skinner, H. B. (2001). Prediction of fracture location in the proximal femur using finite element models. Med Eng Phys, 23(9), 657-664.

Cooper, C., Atkinson, E.J., O’Fallon, W.M., Melton, L.J. III. (1992). Incidence of clinically diagnosed vertebral fractures: A population-based study in Rochester, Minnesota, 1985-1989. J Bone miner Res, 7(2):221-227.

Black, D. M., & Thompson, D. E. (1999). The effect of alendronate therapy on osteoporotic fracture in the vertebral fracture arm of the Fracture Intervention Trial. Int J Clin Pract Suppl, 101, 46-50.

Gunnes, M., Mellstrom, D., & Johnell, O. (1998). How well can a previous fracture indicate a newfracture? A questionnaire study of 29,802 postmenopausal women. Acta Orthop Scand, 69(5),508-512.

Lauritzen, J. B., & Lund, B. (1993). Risk of hip fracture after osteoporosis fractures. 451 women with fracture of lumbar spine, olecranon, knee or ankle. Acta Orthop Scand, 64(3), 297-300.

Melton, L. J., 3rd, Atkinson, E. J., Khosla, S., O'Fallon, W. M., & Riggs, B. L. (1999). Secondary osteoporosis and the risk of vertebral deformities in women. Bone, 24(1), 49-55.