Diagnosis of lesions of the acetabular labrum, of the labral–chondral transition zone, and of the cartilage in femoroacetabular impingement: Correlation between direct magnetic resonance arthrography and hip arthroscopy

Abstract

Objective

To determine the sensitivity and accuracy of direct MR arthrography in the diagnosis of intra-articular lesions associated with femoroacetabular impingement.

Material and methods

We used direct MR arthrography to study 51 patients with femoroacetabular impingement who underwent arthroscopic hip surgery. Surgery demonstrated 37 labral tears, 44 lesions in the labral–chondral transitional zone, and 40 lesions of the articular cartilage. We correlated the findings at preoperative direct MR arthrography with those of hip arthroscopy and calculated the sensitivity, specificity, positive predictive value, negative predictive value, and validity index for direct MR arthrography.

Results

The sensitivity and specificity of MR arthrography were 94.5% and 100%, respectively, for diagnosing labral tears, 100% and 87.5%, respectively, for diagnosing lesions of the labral–chondral transition zone, and 92.5% and 54.5%, respectively, for diagnosing lesions of the articular cartilage. The negative predictive value of MR arthrography for lesions of the labral–chondral transitional zone was 100%. MR arthrography accurately defined extensive lesions of the cartilage and the secondary osseous changes (the main factor in poor prognosis), although its diagnostic performance was not so good in small chondral lesions.

Conclusion

In patients with femoroacetabular impingement, direct MR arthrography can adequately detect and characterize lesions of the acetabular labrum and of the labral–chondral transitional zone as well as extensive lesions of the articular cartilage and secondary osseous changes.

Resumen

Objetivo

Determinar la sensibilidad y la precisión de la artrografía mediante resonancia magnética (artro-RM) directa para diagnosticar lesiones intraarticulares asociadas al pinzamiento femoroacetabular.

Material y métodos

Estudiamos con artro-RM directa a 51 pacientes con pinzamiento femoroacetabular que se operaron mediante artroscopia de la cadera la cual demostró 37 roturas del labrum, 44 lesiones en la unión condrolabral y 40 lesiones del cartílago articular. Correlacionamos los hallazgos de la artro-RM directa preoperatoria con los de la artroscopia de la cadera y calculamos la sensibilidad, especificidad, valor predictivo positivo, valor predictivo negativo e índice de validez de la artro-RM directa.

Resultados

La sensibilidad y la especificidad de la artro-RM directa para diagnosticar la rotura labral fueron del 94,5 y del 100%, para la lesión de la unión condrolabral del 100 y del 87,5%, y para la lesión del cartílago articular del 92,5 y del 54,5%, respectivamente. El valor predictivo negativo de la artro-RM fue del 100% para las lesiones de la unión condrolabral. La artro-RM definió con precisión las lesiones extensas del cartílago y los cambios óseos secundarios, principal factor pronóstico desfavorable, mientras que su rentabilidad diagnóstica fue menor en pequeñas lesiones condrales.

Conclusión

La artro-RM directa detecta y caracteriza adecuadamente las lesiones del labrum acetabular, de la unión condrolabral, lesiones extensas del cartílago articular y los cambios óseos secundarios en pacientes con pinzamiento femoroacetabular.