Limits...
Predicting the location of the hip joint centres, impact of age group and sex

View Article: PubMed Central - PubMed

ABSTRACT

Clinical gait analysis incorporating three-dimensional motion analysis plays a key role in planning surgical treatments in people with gait disability. The position of the Hip Joint Centre (HJC) within the pelvis is thus critical to ensure accurate data interpretation. The position of the HJC is determined from regression equations based on anthropometric measurements derived from relatively small datasets. Current equations do not take sex or age into account, even though pelvis shape is known to differ between sex, and gait analysis is performed in populations with wide range of age. Three dimensional images of 157 deceased individuals (37 children, 120 skeletally matured) were collected with computed tomography. The location of the HJC within the pelvis was determined and regression equations to locate the HJC were developed using various anthropometrics predictors. We determined if accuracy improved when age and sex were introduced as variables. Statistical analysis did not support differentiating the equations according to sex. We found that age only modestly improved accuracy. We propose a range of new regression equations, derived from the largest dataset collected for this purpose to date.

No MeSH data available.


Related in: MedlinePlus

Examples of differentiating slopes according to age category: inter ASIS distance and HJCX (top) and leg length and HJCY (bottom).The regression line drawn from the skeletally matured groups did not generalise (left graphs) and provides minimal or no improvement (Table 2) over the lines drawn from the combined groups (right graphs). Origin of the pelvis is the midpoint between the left and right ASIS and X: posterior-anterior direction, negative is posterior, Y: medial-lateral direction, positive is lateral, and Z: inferior-superior direction, negative is inferior.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC5121588&req=5

f1: Examples of differentiating slopes according to age category: inter ASIS distance and HJCX (top) and leg length and HJCY (bottom).The regression line drawn from the skeletally matured groups did not generalise (left graphs) and provides minimal or no improvement (Table 2) over the lines drawn from the combined groups (right graphs). Origin of the pelvis is the midpoint between the left and right ASIS and X: posterior-anterior direction, negative is posterior, Y: medial-lateral direction, positive is lateral, and Z: inferior-superior direction, negative is inferior.

Mentions: The stepwise regression analysis identified age group as a significant categorical variable for all HJC coordinates and sex was found significant for the posterior-anterior and medial-lateral directions only. However, no interaction (i.e. different slope coefficient according to the categorical variables) was advised for any coordinate with IA and/or LL as predictor(s). Insignificant interaction between predictors and the categorical variables was confirmed visually. Indeed, Fig. 1 illustrates examples of regression equations where the slopes were allowed to change with age groups. The regression line did not fit the skeletally mature group better because the data points are clustered and do not show a clear trend. Figure 2 illustrates regression lines using a single predictor (LL or IA).


Predicting the location of the hip joint centres, impact of age group and sex
Examples of differentiating slopes according to age category: inter ASIS distance and HJCX (top) and leg length and HJCY (bottom).The regression line drawn from the skeletally matured groups did not generalise (left graphs) and provides minimal or no improvement (Table 2) over the lines drawn from the combined groups (right graphs). Origin of the pelvis is the midpoint between the left and right ASIS and X: posterior-anterior direction, negative is posterior, Y: medial-lateral direction, positive is lateral, and Z: inferior-superior direction, negative is inferior.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5121588&req=5

f1: Examples of differentiating slopes according to age category: inter ASIS distance and HJCX (top) and leg length and HJCY (bottom).The regression line drawn from the skeletally matured groups did not generalise (left graphs) and provides minimal or no improvement (Table 2) over the lines drawn from the combined groups (right graphs). Origin of the pelvis is the midpoint between the left and right ASIS and X: posterior-anterior direction, negative is posterior, Y: medial-lateral direction, positive is lateral, and Z: inferior-superior direction, negative is inferior.
Mentions: The stepwise regression analysis identified age group as a significant categorical variable for all HJC coordinates and sex was found significant for the posterior-anterior and medial-lateral directions only. However, no interaction (i.e. different slope coefficient according to the categorical variables) was advised for any coordinate with IA and/or LL as predictor(s). Insignificant interaction between predictors and the categorical variables was confirmed visually. Indeed, Fig. 1 illustrates examples of regression equations where the slopes were allowed to change with age groups. The regression line did not fit the skeletally mature group better because the data points are clustered and do not show a clear trend. Figure 2 illustrates regression lines using a single predictor (LL or IA).

View Article: PubMed Central - PubMed

ABSTRACT

Clinical gait analysis incorporating three-dimensional motion analysis plays a key role in planning surgical treatments in people with gait disability. The position of the Hip Joint Centre (HJC) within the pelvis is thus critical to ensure accurate data interpretation. The position of the HJC is determined from regression equations based on anthropometric measurements derived from relatively small datasets. Current equations do not take sex or age into account, even though pelvis shape is known to differ between sex, and gait analysis is performed in populations with wide range of age. Three dimensional images of 157 deceased individuals (37 children, 120 skeletally matured) were collected with computed tomography. The location of the HJC within the pelvis was determined and regression equations to locate the HJC were developed using various anthropometrics predictors. We determined if accuracy improved when age and sex were introduced as variables. Statistical analysis did not support differentiating the equations according to sex. We found that age only modestly improved accuracy. We propose a range of new regression equations, derived from the largest dataset collected for this purpose to date.

No MeSH data available.


Related in: MedlinePlus