Radiographic risk factors for labral lesions in femoroacetabular impingement.

Background: Tears of the acetabular labrum can lead to pain, disability, and osteoarthritis. Several pathomechanisms have been proposed, including femoroacetabular impingement (FAI). Labral tears have been reported to occur in the presence of even subtle deformities of the acetabulum and femoral head-neck junction.
Questions/purposes: We analyzed the association of the extent of bony deformity and presence and extent of labral lesions in hips with FAI.
Patients and Methods: Radiographs of 123 hips in 116 patients receiving surgical treatment for FAI were analyzed and correlated to the presence and extent of labral lesions. Radiographic parameters of the acetabulum included acetabular index of the weightbearing zone, center-edge angle, inclination of the acetabulum, lateral head extrusion index, and retroversion. On the femoral side, neck-shaft angle, asphericity of the femoral head, superior and anterior alpha angle, offset, and offset ratio were measured. Osteoarthritis was graded according to Tönnis and Kellgren and Lawrence. Labral lesions were graded according to the modified Beck classification. A correlation between labral lesions and age, gender, affected side, type of impingement, and presence and extent of chondromalacia also was tested.
Results: No correlation was found between presence or extent of labral lesions and any radiographic parameter tested, except osteoarthritis classification. The severity of labral lesions correlated to the severity of acetabular chondromalacia as well as patient age (Beck Grade 0 versus Grade 1, Beck Grade 0 versus Grades 1 and 2).
Conclusions: In the presence of impingement-inducing deformity, the extent of deformation is not associated with the incidence of labral lesions. Labral lesions are associated with early degenerative hip disease in FAI.
Level of Evidence: Level I, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.