Is the Cortical Thickness Index a Valid Parameter to Assess Bone Mineral Density in Geriatric Patients with Hip Fractures?

Introduction: Reduced bone quality is a common problem during surgical fixation of geriatric hip fractures. The cortical thickness index (CTI) was proposed to assess the bone mineral density (BMD) of the proximal femur on the basis of plain X-rays. The purpose of this study was to evaluate the inter- and intraobserver reliability of the CTI and to investigate correlation between CTI and BMD in geriatric patients.

Methods: 60 patients (20 pertrochanteric fractures, 20 femoral neck fractures, 20 without fractures) were included. All patients had ap and lateral hip X-rays and measurement of BMD by Dual Energy X-ray Absorptiometry at different areas of the hip. The ap and lateral CTI was measured twice by four blinded observers and correlation between mean CTI and BMD was calculated.

Results: Mean ap CTI was 0.52 and mean lateral CTI was 0.45. Inter- and intraobserver reliability was good for ap CTI (ICC 0.71; 0.79) and lateral CTI (ICC 0.65; 0.69). A significant correlation between CTI and overall BMD was found in patients without fractures (r = 0.74; r = 0.67). No significant correlation between CTI and overall BMD was found in patients with proximal femoral fractures.

Conclusion: The CTI has sufficient reliability for the use in daily practice. It showed significant correlation with BMD in patients without hip fractures. In patients with proximal femoral fractures, no correlation between CTI and BMD was found. We do not recommend the CTI as parameter to assess the BMD of the proximal femur in geriatric patients with hip fractures.