The epidemiology of fractures is surprisingly difficult to define. There are very few large hospitals that treat a defined population. In many countries a privatised medical system means that many, apparently simpler, fractures are treated by a relatively large number of orthopaedic surgeons with complex fractures being treated centrally. The same is true of countries with more sophisticated trauma systems than the United Kingdom where multiply injured patients and complex fractures are treated centrally and other fractures are dealt with in smaller peripheral hospitals. Communication between hospitals is rare. The consequence of this is that fracture epidemiology is extremely difficult to determine and surgeons come to believe that whatever is seen in their hospital mirrors the fracture epidemiology of the overall population. This is clearly incorrect. The Royal Infirmary of Edinburgh is the only hospital treating orthopaedic trauma in a defined adult population and we have analysed fracture epidemiology over several years and present the epidemiology of all fractures seen in a one-year period between July 2007 and June 2008.1
The overall incidence of fractures in patients aged 16 years or more was 13.7/1000/year. In males it was 13.7/1000/year and in females it was 13.6/1000/year. Overall 47.3% of fractures occurred in males with a mean age of 41.4 years (16 to 101) and 52.9% occurred in women with a mean age of 63.0 years (16 to 102). The overall mean age was 52.9 years. The fractures in order of prevalence with the incidence and gender ratios also being shown in Table 1. It is salutary to note that fractures which receive much attention in the literature, such as distal humeral, distal tibial and calcaneal fractures, are relatively rare and that the ten most common fractures actually comprise 84.3% of all the fractures that are seen.
Analysis of the incidence of different fractures at different ages allows fracture distribution curves to be drawn. There are eight different curves which are shown in Figure 1. The overall fracture distribution curve is actually Curve G although this actually applies to relatively few individual fractures. It can be seen that only Curves B and C affect young people and that Curves E and F represent osteoporotic fractures. However 6 of the 8 curves involve the elderly. One can apply the distribution curves to all fractures and this is shown in Table 2 which also shows the distribution curves for different types of fractures. It can be seen that hand and foot fractures mainly affect younger patients but there are many fractures with Type E and F distribution and these should all be regarded as osteoporotic fractures.
Fig. 1. The different fracture distribution curves. See Table 2 for information about different fracture types.
The average age, prevalence and gender ratio for the different modes of injury that cause fractures are shown in Table 3. It is commonly assumed that road traffic accidents are responsible for a high percentage of fractures but this is not the case and falls from a standing height cause almost 60% of all fractures. We accept that figures for other areas may differ by a few percentage points but we doubt that the variation is much and we believe that Figure 3 is representative of all first world countries.
There is no doubt that the spectrum of fractures is changing quickly. A similar analysis by Buhr and Cooke2 of fractures in the Oxford area after World War II showed that fractures of the medial malleolus, metatarsus, distal humerus, tibial diaphysis and clavicle all had a Type C distribution. These fractures now present with Type A, D, G and H distributions with a much higher incidence in older female patients. It is also interesting to look at the work of Knowleden, Buhr and Dunbar3 who analysed fractures in Dundee, Scotland in the 1950s. Comparison of their results with ours shows that the incidence of fractures in males is very similar but the incidence in females has almost doubled. This highlights that the fracture problem is in older females and further analysis of the Edinburgh data suggests that while 30.1% of fractures in males should be considered to be osteoporotic this is true of 66.3% of fractures in females.
It is obvious that fall-related fractures are going to be one of the main problems facing orthopaedic surgeons in the next few decades. It has recently been estimated that 7% of falls result in fracture4 and that about one-third of adults aged ≥ 65 years and living at home, will fall each year5. The Center of Disease Control and Protection in the United States of America has estimated that falls will cost the US economy $54.9 billion in 2020.6
In a recent analysis of fall-related fractures in Edinburgh7 it was shown that 37.5% of male fractures and 77.4% of female fractures followed a standing fall. Age was the main determinant of the prevalence of fall-related fractures. The prevalence of fall-related fractures rose from 54.8% to 80.6% between the fifth and sixth decades in females and from 40.1% to 64.6% between the sixth and seventh decades in males. However further analysis showed that in addition to age, social deprivation plays a role in determining the incidence of fractures.7
In Scotland social deprivation is assessed using the Carstairs score8 which is based on car ownership, overcrowding, employment and social class. It is analysed from postcodes and one can use it to divide the population into 10 deciles based on social deprivation. Decile 1 contains the most affluent population and deciles 9 and 10 the least affluent.
Analysis of the effect of social deprivation on fractures shows that fracture incidence rises with increasing deprivation7 but the greatest effect is seen in deciles 9 and 10. In males the incidence of fractures rises from 294/105/year in decile 1 to 1816/105/year in decile 10 with the equivalent figures for females being 712/105/year and 3374/105/year. However if one examines the prevalence of different fractures in each decile it can be seen that many fractures have a similar prevalence regardless of deprivation. Thus 22% of fall-related factures in decile 1 and 20.6% in decile 10 are distal radial fractures. However analysis shows that 23.5% of all fractures in Decile 1 are proximal femoral fractures whereas only 13.6% of fractures in Decile 10 affect the proximal femur. The explanation for this can be seen in the different life expectancies. In Scotland male life expectancy falls from 80.7 years in Decile 1 to 67.3 years in Decile 10. The equivalent figures for females are 83.5 years and 75.0 years. In the lower social deciles proximal femoral fractures occur at a younger average age but despite this it is clear that many patients in Deciles 9 and 10 do not live long enough to get proximal femoral fractures.7
Fracture epidemiology is important both for clinical, sociological and political reasons. It is clearly changing very quickly and there are many factors which determine fracture epidemiology which, as yet, have received little attention. More research is required to identify which fractures will present to the orthopaedic surgeons of the future.
1. Court-Brown CM, Aitken SA, Forward D, O’Toole RV. The epidemiology of fractures. In: Bucholz RW, Court-Brown CM, Heckman JD, Tornetta P, eds. In: Rockwood and Green’s Fractures in Adults. Seventh ed. Philadelphia: Lippincott, Williams and Wilkins, 2010:53-84.
2. Buhr AJ, Cooke AM. Fracture patterns. Lancet 1959;1:531-6.
3. Knowelden J, Buhr AJ, Dunbar O. Incidence of fractures in persons over 35 years of age: a report to the M.R.C. working party on fractures in the elderly. Brit J Prev Soc Med 1964;18:130-41.
4. von Heideken Wågert P, Gustafson Y, Kallin K, Jensen J, Lundin-Olsson. Falls in very old people: the population based Umeå 85+ study in Sweden. Arch Gerontol Geriatr 2009;49:390-6.
5. Tinetti ME, Speechley M, Ginter SF. Risk factors for falls among elderly persons living in the community. N Engl J Med 1988;319:1701-7.
6. No authors listed. Centres of Disease Control and Prevention: costs of falls among older adults, 2011. http://www.cdc.gov/HomeandRecreationalSafety/Falls/fallcost.html (date last accessed 14 November 2011).
7. Court-Brown CM, Aitken SA, Ralston SH, McQueen MM. The relationship of fall-related fractures to social deprivation. Osteoporos Int 2011;22:1211-18.
8. Carstairs V, Morris R. Deprivation and health in Scotland. Health Bull (Edinb) 1990;48:162-75.