Abstract
It has been observed there is height difference on the left and right sides of the
pelvis in sitting position of one-sided hip flexion limitation cases. However, there is little
report on the relationship between the left and right height difference of the pelvis and one-sided
hip flexion limitation in sitting position. Thus, this study investigated the relationship of
the height difference between the left and right pelvis and the one-sided hip flexion limitation
cases in sitting position. The subjects were 9 individuals with one side total hip arthroplasty.
In sitting position, subjects were photographed from frontal plane. From the taken image, the
lateral pelvic tilt angle was measured using rysis（ sitting posture measurement software）.
Then, the left and right height difference of anterior superior iliac spine（ ASIS） was
calculated［ ASIS height difference＝ASIS distance×sin（ the lateral pelvic tilt angle）］.
Correlation analysis between ASIS height difference and 80- the limited side hip flexion angle
was performed. As a result, a strong correlation between the limited side hip flexion angle
and ASIS height difference（ r＝0.8, p＜0.05） was found. This study showed that one-sided
hip flexion limitation leads to the elevation of the limited side pelvis in sitting position. There
is a possiblity that one-sided hip flexion limitation in sitting position contributes to the
concentration of pressure on one side of the ischium.
