Radiographic Markers of Femoroacetabular Impingement : Correlation of Herniation Pit and Femoral Bump with a Positive Cross-Over Ratio

Abstract EN

Introduction.

The goal of this study was to research the association of femoral bumps and herniation pits with the overlap-ratio of the cross-over sign.

Methods.

Pelvic X-rays and CT-scans of 2925 patients with good assessment of the anterior and the posterior acetabular wall and absence of neutral pelvic tilt were enrolled in the investigation.

Finally pelvic X-rays were assessed for the presence of a positive cross-over sign, and CT-scans for a femoral bump or a herniation pit.

Additionally, if a positive cross-over sign was discovered, the overlap-ratio was calculated.

Results.

A femoral bump was found in 53.3% (n=1559), and a herniation pit in 27.2% (n=796) of all hips.

The overlap-ratio correlated positively with the presence of a femoral bump, while a negative correlation between the overlap-ratio and the presence of a herniation pit was found.

The latter was significantly more often combined with a femoral bump than without.

Conclusions.

We detected an increased prevalence of femoral bump with increasing overlap-ratios of the cross-over sign indicating a relation to biomechanical stress.

The observed decreased prevalence of herniation pits with increasing overlap-ratios could be explained by reduced mechanical stress due to nontightened iliofemoral ligament in the presence of retroversion of the acetabulum.