Abstract
Background
Femoroacetabular impingement due to a reduced femoral head-neck-offset or excessive acetabular coverage will lead to early cartilage lesions of the hip joint. The purpose of the present study was to analyze the relationship between the extent of bony deformity and the presence and extent of cartilage lesions in femoroacetabular impingement.
Methods
On the radiographs of 92 hip joints in 86 patients with a mean age of 36.5 ± 9.2 years who were operated on for with femoroacetabular impingement by surgical hip dislocation, the acetabular index of the weight-bearing zone, the center-edge-angle, the inclination of the acetabulum, the lateral-head-extrusion-index, retroversion signs of the acetabulum, the neck-shaft-angle, asphericity, superior and anterior alpha angles, and superior and anterior offset and offset ratios were assessed and correlated to the presence and extent of chondromalazia.
Results
Acetabular chondromalazia was found in 60 hip joints. Full-thickness delamination of the acetabular cartilage was present in 42 of these hips with an average size of 1.1 ± 0.5 cm2. Femoral-sided chondromalazia was found in 9 hip joints. Hip joints with chondromalazia had a lower center-edge-angle (p = 0.014) and anterior offset ratio (p = 0.028) and a higher lateral-head-extrusion-index (p = 0.029). Hip joints with acetabular cartilage delamination had a significantly lower center-edge-angle (p = 0.012) and anterior offset (p = 0.03) and a significantly higher lateral-head-extrusion-index (p = 0.001) and superior (p = 0.006) and anterior alpha angles (p = 0.003).
Conclusions
Marked cam-type femoral deformity and lesser coverage of the femoral head are associated with the acetabular cartilage lesions, arousing suspicion to the assumption that a large lateral aperture of the acetabulum abets proximal femora with cam-type deformity to inflict cartilage damage in femoroacetabular impingement.
