DOS BULLETIN - Dansk Ortopædisk Selskab

2010-378_DOS nr. 3 2010 29/09/10 10:08 Side 111
Effect of standing position and weight-bearing on
joint space width and pelvic tilt in radiographs of
patients with dysplasia of the hip
Anna Katrine Sundgaard, Maria Grevit, Trine Torfing,
Ole Ovesen, Søren Overgaard
Department of Orthopaedic Surgery and Traumatology, Odense University
Hospital; Department of Radiology, Odense University Hospital
Background: It is generally accepted that the radiographs of the hip are
taken in supine position. It is of interest how radiographic measures differ
in patients with hip dysplasia when changing positioned from supine
to standing knowing that the patient’s functional problem mostly occurs
during weight-bearing.
Purpose: The primary aim of the present study was to determine if
pelvic tilt (represented by the distance between the symphysis and the
sacrococcygeal joint), center edge angle, acetabular index angle, joint
space width, approximated acetabular index of depth to width, femoral
head coverage, posterior wall sign, and cross-over sign differ between
supine and standing weight-bearing position in patients with hip dysplasia.
The secondary aim was to estimate interobserver agreement.
Methods: 23 patients with clinically diagnosed hip dysplasia from the
waiting list for periacetabular osteotomy were included and had supine
and standing weight-bearing standardized anteroposterior pelvic radiographs.
Two readers independently assessed all the radiographs.
Findings: The distance between the symphysis and the sacrococcygeal
joint and center edger angle were reduced in females and males, respectively.
Acetabular index angle increased overall. Minimum joint space
width increased in females. We found no change in acetabular index of
depth to width and femoral head coverage. Posterior wall sign increased
and cross-over sign decreased in the females.
Conclusion: Several of our key-measures changed significantly from
supine to standing position and especially those for evaluation of acetabular
version.Preoperative planning of surgery for reorientation of a retroverted
acetabulum has to be done on both supine and standing weightbearing
radiographs of the pelvis.
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