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· DOS Abstracts
Controversies in imaging measurements and
normal values of Wibergs CE angle in the hip of
young adults
Niels Egund
Dept. Radiology, Aarhus University Hospitals
Background:
One of the most commonly required radiological measurements
of the hip is the Wiberg center edge (WCE) angle. In the literature and by na-
tional orthopedic hip surgeons it has been claimed, that CE angles < 25° rep-
resent hip dysplasia.
Purpose / Aim of Study:
To obtain evidence based national recommendations
of measurement technique and normal values of the CE angle.
Materials and Methods:
Literature review of studies regarding the normal
values of the WCE angle; also, assessment of references used in the literature
justifying recommendations of cut-off WCE angels of 25°.
Findings / Results:
Two different landmarks on the acetabulum have been used
for measurements. The most lateral edge of the acetabulum, is giving the lateral
center edge (LCE) angle and the most lateral point of the acetabular sourcil, is
giving the original WCE. The LCE angle has wrongly been referred to Wiberg.
Based on a small material, Wiberg suggested a cut-off value of 20°. Using the
LCE angle, several studies have confirmed normal cut-off values of 20°. Few
have measured the WCE angle in a larger population of normal young subjects.
The best documented material consists of 2,038 19-year-old Norwegians and
the 2.5 percentile value for the WCE angle was 18° and 17° in males and fe-
males respectively. Using a cut-off angle of 25° for the WCE angle more than
25% of the Norwegian population was calculated to have dysplastic hips. In
most publications using a cut-off angle of 25° in clinical studies of hip dysplasia,
hip impingement and osteoarthritis there is a reference to Wiberg or references,
which in second hand referred to Wiberg.
Conclusions:
The WCE angle indicating hip dysplasia is below 17° - 19°.
The commonly suggested cut-off value of 25° is not confirmed scientifically.
Adequate measurements of the WCE angle require knowledge about normal
imaging anatomy and pitfalls.
No conflicts of interest reported
141.