2. Materials and methods
2.1. Setting
This is a follow up study performed in the trauma unit (unit C) at Complejo Hospitalario Universitario de A Coruña during the period 2009–2011. The inclusion criteria for inclusion were patients operated at the center said above with osteoporotic proximal femur fracture and having provided informed consent during the period of study. Sample size justification: the 100 patients included make possible to estimate the parameters of interest with a confidence of 95% (α = 0.05) and a precision of ±9.8%.