The femoral cortical index (FCI) assesses bone stock using the ratio between the diameter of the femoral shaft and the thickness of the cortical bone calculated 10 cm distal to the centre of the small trochanter in an AP view X-Ray of the femur. Its not clear if low values of FCI may be associated with a condition of altered bone metabolism and bone fragility in fractured patients. The aim of our study is to evaluate a possible association among low values of FCI, risk factors, comorbidities and serum 25 hydroxyvitamin D levels and to establish the importance of FCI as a potential predictor of a new fracture. We conducted a retrospective study on 160 consecutive patients (44 men and 116 women) (range 60 to 103 ya) surgically treated for hip fractures in 2012,after informed consent in our Orthopaedic Department and that never received any medical treatment for osteoporosis. FCI has been calculated by routine clinical radiographs of the pelvis both on fractured femur and on the opposite side. For each patient, we analysed the presence of comorbidities (such as diabetes, hypertension, IRC, rheumatoid arthritis), osteoporosis risk factors and blood levels of vitamin D, usually evaluated in our patients with fragility fractures. Average values of FCI were 0.42 at the fractured femur and 0.48 at the opposite side (range 0.25 to 0.66) with a statistically significant difference. At the fractured side, an average value of 0.45 was found in men, and of 0.40 in women. Patients with severe hypovitaminosis D (serum concentration <12 ng / ml) had a minor FCI compared with those with a moderate deficiency. The presence of comorbidities or osteoporosis risk factors had a different influence on the values of FCI. In our study, we found a correlation among low values of FCI, clinical factors related to bone fragility and severe hypovitaminosis D in elderly patients with hip fractures. Comorbidities and risk factors have a different weight in FCI variations, while the severe hypovitaminosis has a major impact on it. As described in the literature regard the DXA limitations in elderly FCI could be a useful tool in terms of bone fragility evaluation and fracture risk prediction.
Disclosure: The authors declared no competing interests.