Case Report "Comparison of Acetabular Labrum Lesion and Corresponding Cartilage"

May 21, 2007

Introduction

Acetabular labrum morphology changes have been indicated in several studies as a potential reason for hip pain. In cases of femoro-acetabular impingement the changed geometry of the femoral neck causes damage to the acetabular labrum, a possible reason for development of early osteoarthritic changes of the acetabular cartilage. MR Arthrography of the hip is used for diagnosis and indication for therapy in cases of acetabular lesions, but still has a lack of cartilage quality diagnosis. The aim of the ongoing study is therefore to assess the cartilage quality in comparison to the morphology of the acetabular labrum and correlate it with the portion of the labrum based on MRI.

Patient History

A 27-year-old female patient presented with a history of hip pain for the last two years, especially during internal rotations. Clinical examination revealed symptoms of impingement.

Examination

For the MRI examination we used a 3D DESS sequence (isotropic resolution 0.7 x 0.7 x 0.7 mm, Siemens MAGNETOM Trio 3T ) and a radially sectioned PD-TSE sequence (resolution 0.4 x 0.4 x 5.0 mm) perpendicular to the acetabular labrum was performed. For planning of the radial sections the plane of the acetabular opening was assessed double oblique using the isotropic cartilage sequence. The acetabular labrum morphology was analyzed based on shape, grading and the signal intensity in MRI. The results were compared to the corresponding femoral and acetabular cartilage quality based on modified Outerbridge criteria.

Image Findings

We assessed a solid cartilage damage in the anterior part of the femoral head based on the 3D DESS sequence with correlation to the femoral neck geometry. By additional analysis of the PD-TSE sequence in the same orientation we found a mycoid degeneration of the acetabular labrum, based on the mechanical conflict of the femoral head and the acetabular rim. This is an indication for labrum surgery due to the solid cartilage defect and the correlated changes of labrum morphology.

Fig. 1 X-ray with no signs of osteoarthritic changes and reduced acetabular coverage.

Fig. 2 Determination of the acetabular opening (left) for radial planing of the PD-TSE sequence (right).

Fig. 3 Comparision of cartilage quality and acetabular lesion.

Discussion

It was possible to compare cartilage morphology to acetabular abnormalities by using an isotropic cartilage sequence for positioning of the acetabular opening. An affection of the labrum and corresponding cartilage was found in the patient which correlated to femoral bone remodelling. This seems to be a possible cause of osteoarthritic changes in patients with SCFE (Slipped Capital Femoral Epiphysis) and is an indication for joint preserving surgery.

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