DOS 2017

DOS Kongressen 2017 ·

119

Normal values and variation of acetabular angles mea-

sured by computed tomography in normal hips

Inger Mechlenburg, Maiken Stilling, Lone Rømer, Marleen de Bruijne, Kjeld Søbal-

le, Sepp de Raedt

Orthopaedic Department, Aarhus University Hospital; Orthopaedic Depart-

ment, Aarhus University Hospital; Radiology Department, Aarhus University

Hospital; , Erasmus MC Rotterdam; Orthopaedic Department, Aarhus University

Hospital; Department of Clinical Medicine, Aarhus University

Background:

Acetabular angles are commonly measured when assessing a per-

son for hip dysplasia but we have little knowledge of normal values of these

angles.

Purpose / Aim of Study:

The purpose of this study was to report normal

values and variation of acetabular angles and to investigate gender differences.

Materials and Methods:

Retrospectively, we recruited 96 subjects, 52 fe-

males, 63±12 years who had undergone computed tomography (CT) as part

of examination for lymphomas in 2013 at Aarhus University Hospital. After CT,

the subjects completed the Oxford Hip Score. Eight subjects indicated hip prob-

lems and 3 had missing data and those 11 were excluded from the material. The

center-edge (CE), the acetabular-index (AI), the anterior-sector (AASA), the

posterior-sector (PASA) and the acetabular-anteversion angle (AcAV) for both

hips were measured on CT images by an experienced radiologist. The acetabular

angles are reported for right and left hip as mean ± SD degrees and compared

for females and men by a two-sample t-test.

Findings / Results:

The CE angle [right;left] averaged [34±6;35±5]. The AI

angle averaged [3±6;1±5]. The AASA averaged [58±7;60±9]. The PASA av-

eraged [94±7;95±7]. The AcAV averaged [18±5;18±5]. The AASA was lower

(p=0.03), the PASA higher (p=0.04) and the ACAV higher (p=0.0006) for fe-

males compared to men.

Conclusions:

We found considerable variation in the normal values for ace-

tabular angles. There were gender differences in the sector angles and for the

ACAV, the latter supported by previous studies having described the female ac-

etabulum as being more forward-oriented than those of men. Awareness of

normal values is important when we attempt to diagnose the pathological hip

conditions.

No conflicts of interest reported

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