Prognostic Level II. See Instructions to Authors for a complete description of levels of evidence.

As has been demonstrated in previous studies of the hip, this investigation showed osteoarthritis to be associated with increasing age and the severity of dysplasia, as demonstrated both by the Wiberg lateral center-edge angle and the Lequesne anterior center-edge angle. Additionally, we identified a labral tear as being a risk factor for osteoarthritis.

Eight asymptomatic volunteers and 10 patients with early hip osteoarthritis (OA) were investigated with hip delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) at 30, 65, 100, and 135 min after IV injection with Gd-DTPA 2-. In asymptomatic volunteers there was a decrease in the dGEMRIC index (T 1 (Gd)) between 30 and 100 min. In patients the wash-in of Gd-DTPA 2-was faster, with a low T 1 (Gd) at 30 min that did not change significantly over time. Therefore, earlier time points showed a larger separation in T 1 (Gd) between asymptomatic and OA hips, with more convenient timing logistics. However, T 1 (Gd) at 30 min had a larger standard deviation (SD) in the OA group, possibly due to variability of the steep slope of wash-in. This sensitivity to the imaging window may be less desirable for longitudinal studies in which reproducibility is a concern. At all time points, T 1 (Gd) was 20 -30% lower in patients than in asymptomatic volunteers (P < 0.003), which demonstrates the sensitivity of dGEMRIC to early hip OA. Magn Reson Med 57: 803-805, 2007.

Purpose:To determine the feasibility of assessing early osteoarthritis (OA) in hips with femoroacetabular impingement (FAI) using delayed Gadolinium enhanced MRI of Cartilage (dGEMRIC). Materials and Methods:Thirty-seven hips in 30 patients who had a dGEMRIC scan and radiographic evidence of FAI were identified. Clinical symptoms were assessed. Radiographic measurements were performed to determine acetabular and femoral morphology. The severity of radiographic OA was determined using Tönnis grade and minimum joint space width (JSW). On MRI, the alpha angle was measured on the sagittal oblique slices. Correlations between dGEMRIC index, patient symptoms, morphologic measurements, radiographic OA, and age were determined.Results: Significant correlations were observed between dGEMRIC index, pain (P Ͻ 0.05), and alpha angle (P Ͻ 0.05). The correlation of dGEMRIC with alpha angle suggests that hips with more femoral deformity show signs of early OA. Conclusion:The results of osteoplasty for FAI depend on the amount of pre-existing OA in the joint. dGEMRIC may be a useful technique for diagnosis and staging of early osteoarthritis in hips with impingement.