Article

Acetabular retroversion may result in anterior acetabular
over-coverage and posterior deficiency. It is unclear how standard radiographic
measures of retroversion relate to measurements from 3D models, generated from
volumetric CT data. We sought to: (1) compare 2D radiographic measurements
between patients with acetabular retroversion and normal control subjects, (2)
compare 3D measurements of total and regional femoral head coverage between
patients and controls, and (3) quantify relationships between radiographic
measurements of acetabular retroversion to total and regional coverage of the
femoral head. PATIENTS AND METHODS: For 16 patients and 18 controls we measured
the extrusion index, crossover ratio, acetabular angle, acetabular index, lateral
center edge angle, and a new measurement termed the "posterior wall distance". 3D
femoral coverage was determined from volumetric CT data using objectively defined
acetabular rim projections, head-neck junctions, and 4 anatomic regions. For
radiographic measurements, intra-observer and inter-observer reliabilities were
evaluated and associations between 2D radiographic and 3D model-based measures
were determined. RESULTS: Compared to control subjects, patients with acetabular
retroversion had a negative posterior wall distance, increased extrusion index,
and smaller lateral center edge angle. Differences in the acetabular index
between groups approached statistical significance. The acetabular angle was
similar between groups. Acetabular retroversion was associated with a slight but
statistically significant increase in anterior acetabular coverage, especially in
the anterolateral region. Retroverted hips had substantially less posterior
coverage, especially in the posterolateral region. INTERPRETATION: We found that
a number of 2D radiographic measures of acetabular morphology were correlated
with 3D model-based measures of total and regional femoral head coverage. These
correlations may be used to assist in the diagnosis of retroversion and for
preoperative planning.

Langue : ANGLAIS