Epidemiology of ankle fractures

Κ. Papageorgiou, Τ. Liakos, K. Evmiridis
Orthopaedics Clinic, General Hospital of Drama, Greece

Key words: Malleolar, epidemiology, prevention.

Ιndroduction
Ankle fractures are the second most frequent injuries, after fractures of the lower part of the radius (Solgard & Petersen, 1985). They are everyday fractures and, yet, bibliography referring to their epidemiology is poor. In 1969, Νilsson, from Malmo, studied their overall incidence rate in terms of age and gender. In 1986, Begner & Johnell study the incidence rate in a 30 year study, where it is pointed out that fractures, especially those of the lateral malleolus, are age dependent for men over 60 years of age and women over 50. Another study from Minessota presents conclusions from other indications and regards athletics as the commonest cause of injuries (Daly et al, 1987). 10 years later, Jensen et al (1998), from Denmark, study these fractures in a survey among 212 patients, where it is stressed that a fracture is caused by insignificant violence during physical exercise. The aim of this study is, through focusing on the epidemiological character of the fracture, to point out the possibility to reduce the frequency and morbility, within the framework of prevention.

Table 1: Prefecture of Drama - Composition of people according to sex and origin.
Census of Greece, March 1991.

Table 2: Distribution per age, total and per year.
Sample X N Sample p 95,0% Lower Bound Z-Value P-Value
1 46 154 0,298701 0,238036 1,40 0,081 o,298>05

Table 3: Distribution per sex, total and per year.
Test of p = 0,5 vs p > 0,5
Sample X N Sample p 95,0% Lower Bound Z-Value P-Value 0,552<0,5
1 95 154 0,616883 0,552446 2,90 0,002

 

Table 4: Cause of injury total and per year.
Test of p = 0,25 vs p > 0,25
Sample X N Sample p 95,0% Lower Bound Z-Value P-Value
1 61 154 0,396104 0,331277 4,19 0,000 0,396<05

Material - Method
During the years 1999-2002, we studied the cases of 154 patients with ankle fractures, aged from 15 to 50 years. Considering that the population equivalent to the above-mentioned age-spectrum is 59,776 people, the resulting incidence rate is 91 fractures per 100,000 individuals per year.
Eight epidemiological indicators were studied and were evaluated, as follows:
1.) Age: active age groups were included, while osteoporosis was excluded as a factor that could lead to false conclusions.
2.) Sex: correlation of the fracture to the sex and comparison of the woman’s status in terms of employment and athletics.
3.) Causes: the commonest causes were studied; everyday activities, traffic accidents, and sports.
4.) Origin: according to the composition of the population in urban, semi-rural and rural areas.
5.) Placement: refers to the relation between the fracture and the predominant limb.
6.) Escort injuries: refers mainly to the relation to high violence that follows traffic accidents.
7.) Treatment: the resulting morbility and methods of treatment and cost are examined.
8.) Mechanism: the most probable mechanism and the most frequent type of fracture are examined.

 

Table 5: Origin of patient total and per year.
Sample X N Sample p 95,0% Lower Bound Z-Value P-Value
1 69 154 0,448052 0,382138 3,03 0,001 0,448<05

Results
Based on the statistic schedule of analisis, the level of the substativeness, p 0.25 or p 0.5, is defined according to the number of the qualitative datas, and the statistically important rate (p-value) is defined as the minor of p (p-value < p). Based on the plan and the terms of the study, analysis and evaluation of the epidimiologic parameters provided the following data:
1.) Age: patients of the second and third decade predominated, due to intense activity and exposure to potential dangers (Table 2).
2.) Sex: clear predominance of male patients, in the whole of the population and throughout the time of the study, the ratio being 1.6:1 (Table 3), because of age predominance and physical activity (labor, athletics).
3.) Causes: predominance of everyday-life falls, at a rate of 39%, and amateur sporting activity, by weekend athletes or, as referred to in the Anglo-Saxon bibliography, by “white-collar athletes”. Traffic accidents and labor accidents follow at quite low rates (Table 4).
4.) Origin: statistically insignificant predominance of rural areas, which indirectly confirms the aspect that all population groups are exposed to fracture (Table 5).
5.) Placement: an overall predominance of the right side, which is not evaluable or related to the predominant limb (Table 6).
6.) Associated injuries: They were found at a low rate (39%), due to insignificant violence, and 1/3 were fractures of the small bones, when the ankle fracture was an associated injury, caused by traffic accidents (Table 7).
7.) Treatment: predominance of conservative treatment, without hospitalization or including hospitalization for a few days. Usually 1/3 patients undergo an operation. Conservative treatment predominates both on the whole population and per year (Table 8).
8.) Type of fracture: 3/4 of all patients had an isolated fracture of the ankles and 85% of these were fractures of the lateral malleolus (Tables 9,10).

Table 6: Location of fracture.
Test of p = 0,5 vs p > 0,5
Sample X N Sample p 95,0% Lower Bound Z-Value P-Value 0,446<05
1 79 154 0,512987 0,446736 0,32 0,374

Table 7: Associated injuries.
Test of p = 0,5 vs p > 0,5
Sample X N Sample p 95,0% Lower Bound Z-Value P-Value 0.870>05
1 140 154 0,909091 0,870987 10,15 0,000

 

Table 8: Choice of treatment tota and per year.
Test of p = 0,5 vs p > 0,5
Sample X N Sample p 95,0% Lower Bound Z-Value P-Value
1 109 154 0,707792 0,647513 5,16 0,000 0,647>05

 

Table 9: Type of fracture total and per year.
Test of p = 0,33 vs p > 0,33
Sample X N Sample p 95,0% Lower Bound Z-Value P-Value
1 102 154 0,662338 0,599655 8,77 0,000 0,599>05

 

Table 10: High percentage location in lateral malleolus.
Test of p = 0,5 vs p > 0,5
Sample X N Sample p 95,0% Lower Bound Z-Value P-Value
1 129 154 0,837662 0,788785 8,38 0,000 0,788>05

 

Discussion
Epidemiology of the ankle fractures varies, depending on social class and economic development (industrial areas, possibility of mass sports activities). Incidence rates, such as 107/105 per year (Jensen et al, 1998), 114/105 per year (Lindsjo et al, 1981), 184/105 per year (Daly et al, 1987), are mentioned. Younger ages (20-30) are exposed mainly, whereas men predominate, due to intense activity. After the age of 40, women present the same incidence rate as men, because of a decline of the quality of bones, similar to what happens with hip fractures (Daly et al, 1987 - Hasselman et al, 2003). These fractures are 1.5 times more frequent than hip fractures and reach the 60% of the number of fractures of the lower part of the radius (Solgaad & Petersen, 1985). Mass sports activities, especially when performed without guidance, are an important cause of the injury, at percentages varying: 26% (Jensen et al, 1998), 35% (Begner & Johnell, 1980), 40% (Karlsson et al, 1993), 36% (Daly et al, 1987). 9/10 of these fractures are caused by indirect violence and everyday activities. The usual mechanism is supination, adduction and lateral rotation of the talus (Brown et al, 1998 - Palombi, 1991).
Conservative treatment clearly predominates surgical treatment, 1/3 of the patients undergoing an operation. Including both malleoli, the lateral malleolus predominates considerably, due to both mechanism and topography (it is more superficial and exposed (Reuwer & Shaten, 1984 - Zenker & Nerlich, 1982 - Meyer & Kumler, 1980). In detail, isolated fractures concern 2/3 of the series, 1/4 are bimalleolar, 7% are trimalleolar and 2% are open fractures (Court-Brown et al, 1998).
It appears that in younger ages there is a predominance of sprains, while in older ages the predominance is of fractures, because of the relation between the quality of the bones and the joint endurance changes (Jensen et al, 1998). This is a study at random and refers to a small sample of population, so we can make some remarks and reach conclusions in terms of the cost of hospitalization, the loss of day’s wages and insurance charges, taking the following data into account:
1.) Based on the incidence of the fracture (91/105people/year), the predictable number of fractures of the maleollar bones for 130,000 habitants is 120 people (per year).
2.) By the national collective convention of labor, for the years 2002-2006, the day’s wage for an unskilled worker, married, with 2 triennium, is 54 euros, considering work of five days per week. The cost for the general hospitals is closed and corresponds to 73 euros, whereas the customary materials for osteosynthesis for the maleollars cost up to 150 euros.
3.) From the 120 predictable fractures of maleollars, 1 out of 3 is expected to be operated upon; 40 of the freactures will undergo operation, while the rest 80 will be treated conservatively.
4.) The predictable time of hospitalization for the fractures that are going to be operated upon is 5-7 days and the time of rehabilitation and return to work is, approximately, 12-14 weeks. Such values for fractures receiving conservative confrontation are 2-3 days and 6-7 weeks, correspondingly.
With such data available, as shown above, we predict:
A.) 5,200 day’s wages will be lost.
B.) 535 days of hospitalization will be demanded.
C.) The cost of insurance charges and loss in day’s wages will reach the amount of 288,000 euros.

Conclusions – Observations
Conclusively, we can attribute the following characteristics regarding the fracture of the maleollar: a) it is the everyday-life fracture, b) the active groups of population are the most vulnerable, c) regarding social class composition, farmers are the most exposed, d) mass sports activities, without guidance or proper information, are an important cause, and, e) out of 8 epidemiological parameters, 4 presented a statistically significant predominance on the whole of the population and during the whole time; this adds relative reliability in our study.

References
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