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International Journal of Anatomical Sciences 2010,1:1-6

Research Paper

Correlation of Anthropometric and Upper Femoral, Morphometrics with Osteoporotic Related Hip Fracture Risk

Prabhu K,a Vathsala V,a Mani R,b Johnson WMS.a

Department of Anatomy; bDepartment of Orthopaedics, Sree Balaji Medical College and  Hospital, Chromepet , Chennai 600 044, India

Key Words: hip fracture, bone mineral density, femoral morphometry

 Abstract: Hip fractures have high morbidity and mortality among people and are generally seen in elderly population. In this study our focus was to know the relation of anthropometric factors and proximal femoral morphometry with fracture risk. Total of 107 women were recruited in this study. Determination of Bone mineral density by DXA scan is gold standard in prediction of osteoporotic related hip fracture. Based on scores of BMD we divide the Participants into two groups.

1. Fracture risk group and

2. Non fracture risk group. Age, BMI, hip axis length (HAL), neck shaft angle (NSA), and   neck   width   (NW),   were   recorded   and   measured   from   the   dual   x-ray absorptiometry (DXA) print out. Age had negative relation with BMD and BMI had positive relation with BMD. HAL and NSA were more in fracture risk group. So our study suggests that, one should strive to use both geometry and BMD to predict the susceptibility to fracture in patients.

 The number of hip  fractures  has  been estimated to rise from 1.7 million in 1990 to 6.26 million by the year 2050, worldwide and this is mostly due to the increasing life expectancy and increasing size of the population in nearly all countries (Cooper et al., 1993). It increases the morbidity and mortality in elderly men and women (Baudoin et al., 1996).

 Many risk factors are there to define the etiology of hip fracture. Age, diseases and trauma are the three main causes that play an important role in the etiopathology of hip fractures. (Alffran et al., 1964). It is also an outcome of age related osteoporosis. Alffran  Correspondence to: Prabhu K, Department of Anatomy, Sri Balaji Medical College, Chrompet, Chennai 600 044, India.

Email: [email protected]

Accepted :26-May-2010 et al., (1964) emphasize the importance of osteoporosis as a predisposing factor in hip fractures. Together with age and gender, bone mineral density measurement is one of the reliable methods to evaluate the risk of osteoporotic –related hip fractures

 The other potential risk factors for hip fracture are lower body weight, cigarette smoking, caffeine intake, use of long acting sedatives and inactivity. Other risk factors such as density also relate to the strength of the bone (Cheng et al., 1997 ).The reduced bone mass during aging alone does not explain this phenomenon (Ramalho et al.,2001), and other factors such as decreased muscle mass (Dargent–Molina et al., 1996), postural instability, bone quality (Cumming et al., 1995; Dargent–Molina et al., 1996), genetic  factors  like  polymorphism  in  the type   2   collagen   synthesizing   gene   that would alter the bone structure (Quershi et al., 2000) and also the geometry of the proximal femur (Gnudi et al., 2002) are also  suggested   to   cause   fracture.   So   Many studies have been carried out to prevent fractures, as most hip fractures follow a fall.

Recently  authors  tried  to  estimate the risk of fracture through measurement of hip geometry like hip axis length, neck shaft angle, neck width with DXA scan. (Pande et al., 2000; Gnudi et al., 2002; Alonso et al.,2000).

 As the great majority have used the densitometry scan image to measure the geometric values mentioned above, we also used DXA scan to measure femoral geometry. To determine whether the geometric measurement of morphological features of the proximal femur are independent predictors of hip fracture and whether   they   improve   the   discriminate ability of the femoral bone mineral density (BMD), we measured and compared the hip axis length, the femoral  neck width, neck shaft angle and the femoral BMD of randomly selected individuals with and without  hip  fracture  risk  by  taking  a  hip scan using dual x- ray absorptiometry (DXA)). The recent interim report from the world health organization (WHO) task force for osteoporosis, recommends using only bone  mineral  density  (BMD)  for determining the fracture risk.

 Earlier  studies  carried  out  in different ethnic groups have found that the incidence   of   hip   fractures   differ   from country to country. This evidence suggests that like others factors, proximal femoral morphometry, may equally be important in determining hip fracture risk.

Materials and Methods

 This  study  was  conducted  on  107 post menopausal women in the age group 50 – 60 years, who visited bone clinic for screening of osteoporosis. The experimental procedure was approved by the local ethics committee. We divided the participants into two groups based on the following criteria.

Control group (n= 57) Women who had normal BMD as per WHO criteria (T >-1 SD) were included in this group. Fracture risk group (n= 50). Women who had osteopenia (T <-1SD TO >-2.5) or osteoporosis (T<-2.5 SD) were included in this group.

For both the groups age , BMI, HAL,NSA, NW, and BMD were recorded and  measured  from  their DXA  scan  print out. All values were statistically correlated using SPSS statistical package.

Exclusion criteria for the study were hip fracture, any metabolic bone disease, or treatment with sex hormones like calcitonin. The information consent was obtained from the subjects to take secondary data from the DXA print out.

The following parameters were considered and measured for this study:

o BMD values of the proximal femur at neutral  position,  calculated  by  DXA scan (Lunar DPX).

o Age, recorded from patient’s history.

o Body height and weight were measured with        an   anthropometer   and   beam- balance scale.

o Body mass index  was  calculated from height and weight measurements, using the formula Weight / Height in meter2

Following  morphometrics  were  measured   (refer Fig. 1).

 Hip axial length (HAL) was measured as the linear distance from the base of greater trochanter to the apex of the acetabular rim by aligning the ruler manually during the analysis procedure with the software provided with the device.

 Femoral neck width (NW) was measured as the shortest distance within the femoral neck perpendicular to the femoral neck axis.

 The angle between the hip axial length and shaft axis gives neck shaft angle (NSA).

Fig. 1  DXA print out

Observations

The mean values of the anthropometric parameters like age , BMI, and upper femoral morphometric parameters  positive correlation with BMD (r = 0.339  BMD, p = 0.000). HAL had positive correlation  with  age(r=0.303;  p  =  0.002), and NW (r=0.342; p = 0.000). NSA had negative correlation with BMD (r = -0.239; p = 0.013). NSA had negative relation with age (r =-.282 p= .003). BMD had negative correlation with age, (r = – 0.267 p = 0.005), with HAL(r = – 0.389; p = 0.000).

Table 1 The mean and standard deviation of the Physical characteristics namely age, BMI, HAL, NW, NSA and BMD of the participants

 

	Mean	Std. Deviation	N
AGE	51.93	12.177	107
BMI	26.8741	4.39041	107
HAL(cm)	5.6514	0.31244	107
NW	1.7645	0.17170	107
NSA (degree)	128.29	7.464	107
Area	29.2547	3.42380	107
BMC	24.8940	6.09370	107
BMD	0.85468	0.177891	107

 

Table 2 Averages and standard deviations of anthropometrics and femoral morphometrics of non fracture risk group in women

like HAL, NSA, NW of 57 non fracture risk Chennai  control  group  were  found  to  be

Mean         Std. Deviation          N

 50.44               12.177             57

26.8741         4.39041            57

5.55                .31244               57

1.74              .17170                57

127.8               7.464              57

0.8679          .177891            57

Table 3 Averages and standard deviations of anthropometrics and femoral morphometrics  of  fracture  risk group in women

53.60                  12.517                50

26.8741             4.3224                 50

1.7800                .17170                50

128.78                    7.265                50

0.6370                 .15789                50

5.6400                .31321                50

Table 4 Correlation between femoral morphometrics, anthropometrics and BMD of both fracture and non fracture groups in women.

 

	AGE	BMI	HAL (cm)	NW	NSA (degree)	AREA	BMC	QMD
AGE               Person Correlation Sig.(2-tailed) N	1  107	0.109  0.264 107	0.303**  0.002 107	-0.18  0.851 107	-0.282** .003 107	0.375**  0.000 107	-0.066  0.501 107	-0.267** 0.005 107
BMI                 Person Correlation Sig. (2-tailed) N	0.109  0.264 107	1      107	-0.182  0.061 107	0.106  0.276 107	0.072  0.464. 107	0.154  0.113 107	0.380**  0.000 107	0.339**  0.000 107
HAL(cm)         Person Correlation Sig.(2-tailed) N	0-303**  0.002 107	-0.182  0.061 107	1      107	0.342**  0.000 107	-0.004  0.964 107	0.342**  0.000 107	-0.199*  0.040 107	-0.389** 0.000 107
NW(cm)           Person Correlation Sig.(2-tailed) N	-0.018  0.851 107	0.106  0.276 107	0.342**  0.000 107	1      107	-0.102  0.298 107	0.515**  0.000 107	0.220*  0.023 107	-0.025  0.801 107
NSA(degree)    Person Correlation Sig.(2-tailed) N	-0.282** 0.003 107	0.072  0.464 107	-0.004  0.964 107	-0.102  0.298 107	1      107	-0.099  0.311 107	0.136  0.163 107	-0.239*  0.013 107
AREA              Person Correlation Sig.(2-tailed) N	0.375**  0.000 107	0.154  0.113 107	0.342**  0.000 107	0.515**  0.000 107	-0.099  0.311 107	1      107	0.512**  0.000 107	0.036  0.716 107
BMC               Person Correlation Sig.(2-tailed) N	-0.066  0.501 107	0.380**  0.000 107	-0.199*  0.040 107	0.220  0.023 107	0.136  0.163 107	0.512**  0.000 107	1      107	0.862**  0.000 107
BMD               Person Correlation Sig.(2-tailed) N	-0267**  0.005 107	0.339**  0.000 107	-0.389** 0.000 107	-0.025  0.801 107	-0.239*  0.013 107	0.036  0.716 107	0.862**  0.000 107	1      107

**        Correlation Is significant at the 0.01 level (2-tailed)

*          Correlation is significant at the 0.05 level (2-tailed)

Discussion

 India is a large country with a wide variety of environmental conditions. It shows ethnic multiplicity and is characterized by an interracial mixing rarely seen in other countries. Taking into account of these factors the data base obtained in our study may  not  be  representative  of  the  entire Indian    population    and    therefore    our normative data should be used only for a population  sharing  the  same  genetic potential and living under similar environmental conditions. One limitation of our study was the recruitment of volunteers. The study sample was not population based but recruited from the subjects who visited bone clinic. It is possible that this may introduce a selection bias focusing on the wealthier  and  better  educated  part  of  the   population or alternatively on those who through  life style or living conditions are prone to osteoporosis.  To our knowledge, this is the first study of BMD in a large south Indian population using DXA measurements. In the present study we cannot exclude cohort effects such as socio economic status, life time exercise patterns or nutritional habitat. A survival bias may also have occurred since we made bone measurements only in the individuals able to come to the outpatient clinic.

 The hip axis length has been found to be correlated with the risk of fracture (Nakamura et al., 1994). Our result also shows higher value of HAL in fracture risk group ref table 3.The precise physical mechanism of this is unknown. However Faulkner is of the opinion that a longer hip axis length leads to a higher probability of impacting the great trochanter and to lower impact  absorption  after  a  fall.  (Faulkner,1995; Schwartz et al., 1999).

 In  our  study  the  neck  shaft  angle also  discriminated  healthy  from osteoporotic subjects. Neck –shaft angle varies among the published studies on fracture risk. In every comparison study except those of Cody and Nahigian in 1993 (a CT study) and Ferris et al., in 1989, (where hips were held in maximum internal rotation), the NSA is larger in the fracture – prone group. Our method of femoral NSA measurement proved both reliable and precise. Furthermore the mean values and ranges are similar to those reported in other studies (Alonso et al., 2000; Gnudi et al.,2002; Faulkner et al., 1993; Quershii et al.,2001). Our study also anticipates that larger NSA to be associated to an increased hip fracture risk in later life. But our data regarding NSA was in contrast to those of Faulkner et al., (1993) who report no association  between  neck  shaft  angle  and hip fracture risk.

 Ex vivo biomechanical tests also shows   that   neck   shaft   angle   does   not   correlate with femoral neck strength (Cheng et al., 1997; Schwartz et al., 1999). So it correlation  to  fracture  risk  may  involve other mechanism.  It may be hypothesized that neck shaft angle or the ante version angles interact with the direction of the fall, thus affecting the femoral neck loading angle. This angle, according to Pinilla et al., (1996) is inversely related to fracture load and its variation may therefore be associated with different fracture risk.

 These discrepancies may be due to racial differences in the neck shaft angle Nakamura et al., (1994) or to different compensations of the anteversion angle during positioning of patients on the scan bed producing different effects on this measurement.  The  occurrence  of  hip fracture may also be influenced by anthropoimetric   factors   (Farmer   et   al.,1989).   Aging   is   one   of   the   important reasons for hip fracture. It increases exponentially  with  age  (Cumming  et  al.,1989). Many studies show that short individuals have a lower risk of hip fracture compared to tall individuals (Hemenway et al., 1995).

 Conclusion

Non  invasive  imaging   techniques can provide measures of geometry and a correlate to macroscopic material properties (BMD).  Until  we  have  effective  methods for  measuring  micro  architecture  and genetic or other biomarkers for individual response dynamics, we should strive to use both geometry and BMD to predict the susceptibility to type of fracture in patients

References

Alffram PA (1964) An epidemiological study of cervical and trochanteric fractures of the femur in  an  urban  population.  Acta  Orthop  Scand Suppl 65.

Alonso  CG,  Curiel  MD,  Caranza  FH,  Cano  RP, Perez AD (2000) Femoral bone mineral density, neck –shaft angle and mean femoral neck width as predictor of hip fractures in men and women.