Epidemiology

Hip fracture is a collective term for several different types of fracture in the proximal part of the femur. The two main fracture types are fracture of the femoral neck (cervical fracture) and fracture through the muscle insertions distal to the femoral neck (pertrochanteric and intertrochanteric fracture). Intermediate types are called basocervical fracture. Fractures of the trochanteric area which extend 5 cm distally below the lesser trochanter, are termed subtrochanteric fractures. Treatment and healing prognosis differ. The risk of acquiring a hip fracture increases exponentially from 50 years of age onwards. The relationship of women / men has been 75/25 % (Holmberg and Thorngren 1987 Thorngren 1994). However, today the registration shows a higher incidence in men (30%). The high proportion of women is explained by the high population of elderly women and the increasing incidence of osteoporosis in the postmenopausal period. Hip fractures in patients younger than 50 years are rare and constitute only 2 percent of all hip fractures in Sweden. The lifetime risk for a woman is almost 20% which means that every fifth woman at the age of 80 have had a hip fracture. At the age of 90 years almost every second woman has had a hip fracture (Thorngren 1995).

Hip fractures are mostly fragility fractures due to osteoporosis. The incidence of hip fracture increases with age. Fractures depend on the interaction of skeletal resistance and the force that is directed at the bone, usually by a fall. With increasing age both osteoporosis and general disability with tendency to falls increase. Already in 1824, Sir Astley Cooper described the prevalence of cervical hip fractures from a hospital perspective. Then 0.6 % of the patients in the hospital had hip fracture. Today about 20-25 % of the beds are occupied by hip fracture patients in the Swedish orthopaedic departments (which have primary responsibility for the hip fracture patients). In 1964, Knowelden showed that the incidence of hip fractures increased in Dundee and Oxford in the 1950s. Stewart (1955) and Mårtensson (1962) also showed an increase in hip fracture incidence in the 1950s in England and Sweden. Nilsson and Obrant (1978) showed an incidence increase during the 1960s in Malmö and Zetterberg and Andersson (1982) showed the same during the 1970s in Gothenburg. The incidence has also increased in Lund (Hansson et al, 1982; Jarnlo others 1989). Hundreds of studies have later been published and all shows an increase in incidence in Scandinavia but also in the rest of the world. It has also been shown that the incidence is higher in urban populations than in rural areas. During the last decades the incidence has been constant. Different risk factors have been studied and all that increase osteoporosis – including age and impaired muscle function and other factors that increase the risk of falling – are listed as risk factors. In the 1990s, there was an increase in the number of hip fractures, mainly because of more people getting older. Only part of this increase is due to increased longevity.

Manifest osteoporosis with fractures is common in Scandinavia, where Sweden and Norway have the highest age-adjusted incidence rate (in terms of the annual addition) of hip fractures in the world (Cummings et al, 1985, Johnell et al, 1992, Lauritzen et al 1993 , Cooper et al, 1992, Melton et al 1992). The reasons for this are not clear. It could possibly be a link between heredity of skeletal size, low physical activity and incomplete diet and that people in the northern counties might have insufficient production of vitamin D since sunshine stimulates the production. The number of hip fractures has significantly increased in recent decades, both in Scandinavia and in other parts of the Western world. Now annually around 18 000 Swedish men and women get a hip fracture. This increase will probably continue, mainly due to an increased number of elderly in the population, but also to some extent on an increased risk of fractures especially in the elderly over 80 years of age. Because of other diseases that may need treatment, hip fracture in these elderly patients initiate extensive needs for care. However, with improved treatment, including active rehabilitation, the prognosis has improved considerably in recent years. Now, the majority of patients with a hip fracture rapidly can return to their own home and achieve the same level of function as before the fracture (Thorngren 1998).

 

References

Cooper C, Campion G, Melton LJ 3rd. Hip fractures in the elderly: a world-wide
projection
. Osteoporosis Int 1992;2(6):285–9.

Cummings SR, Kelsey JL, Nevitt MC, ODowd KJ. Epidemiology of osteoporosis
and osteoporotic fractures.
Epidemiol Rev 1985;7:178––208

Hansson LI, Ceder L, Svensson K, Thorngren K-G. Incidence of fractures on the
distal radius and proximal femur: comparison of patients in a mental hospital and the general population.
Acta Orthop Scand 1982;53(5): 721-6.

Holmberg S, Thorngren K-G. Statistical analysis of femoral neck fractures based on 3053 cases. Clin Orthop Rel Res 1987;218:32–41

Jarnlo G-B, Jakobsson B, Ceder L, Thorngren K-G. Hip fracture incidence in Lund, Sweden, 1966-1986. Acta Orthop Scand 1989;60(3): 278-82

Johnell O, Gullberg B, Alander E, Kanis JA and the Medos Study Group. The
apparent incidence of hip fracture in Europe: A study of national register sources.
Osteoporosis Int 1992;2:298–302

Lauritzen J B, Schwartz P, Lund B et al. Changing incidence and residual life time
risk of common osteoporosis-related fractures
. Osteoporosis Int 1993;3:127–132

Melton LJ, Chrischilles EA, Cooper C, Lane AW, Riggs BL.How many women
have osteoporosis?
J Bone Miner Res 1992;7:1005–1010

Mårtensson L. Är svensk sjukhusplanering ändamålsenlig? Statistiska undersökningar rörande collumfrakturens frekvens. (In Swedish). Läkartidningen 1962; 59:3185–3200

Naessén T, Parker R, Persson I, Zack M, Adami H-O. Time trends in incidence
rates of first hip fracture in the Uppsala health care region, Sweden, 1965–1983
. Am J Epidemiol 1989; 130:289–299.

Nilsson BE, Obrant KJ. Secular tendencies of the incidence of fracture of the upper end of the femur. Acta Orthop Scand 1978;49(4):389–91

Socialstyrelsens riktlinjer för vård och behandling av höftfraktur. Socialstyrelsens skrifter 2003, sid 1-137. Artikelnr 2003-102-1. ISBN 91-7201-758-9.

Stewart JM. Fractures of the neck of femur. Incidence and implication. Br Med J 1955;1:698–701.

Thorngren K-G. Fractures in the elderly. Acta Ortop Scand (suppl 266) 1995;
66:208–210.

Thorngren K-G. State of the Art – Höftfraktur. 1998

Zetterberg C, Andersson GB. Fractures of the proximal end of the femur in Göteborg, Sweden, 1940-1979. Acta Orthop Scand 1982;53(3):419-26