Patterns of labral tears and cartilage injury are different in femoroacetabular impingement and dysplasia

The aim of this study was to assess injury patterns and risk factors of the acetabular labrum and associated cartilage in patients with femoroacetabular impingement (FAI) versus dysplasia. We retrospectively reviewed 137 patients diagnosed with labral tears and FAI or dysplasia (74 or 63 cases, respectively) through an arthroscopic procedure. Labral and concomitant cartilage injuries were evaluated. Demographics and radiological variables [lateral center-edge angle (LCEA), anterior center-edge angle, acetabular index (AI), acetabular version and alpha angle] were evaluated as risk factors for labral and cartilage injuries. Detachment of acetabular cartilage with intact labro-cartilaginous junction was the most common in dysplasia, whereas cartilage delamination from the labro-cartilaginous junction was more common in FAI (P < 0.001). A higher body mass index was significantly associated with delamination injury in FAI (odds ratio 1.226; 95% CI 1.043-1.441; P = 0.013). A significant correlation was evident between detachment injury and a larger AI in dysplasia (odds ratio 1.127; 95% CI 1.000-1.270; P = 0.049). In addition, symptom duration was positively correlated with the extent of labral tearing in FAI (P = 0.013), whereas the smaller LCEA was correlated with the larger extent of labral tearing in dysplasia (P = 0.044). FAI and dysplasia patients exhibited different labral and cartilage injury patterns. Increased body mass index was correlated with delamination injury in FAI, whereas an increased AI was associated with detachment injury in dysplasia. Greater tearing was associated with a longer symptom duration in FAI, and a decreased LCEA was a risk factor for the extent of tearing in dysplasia.