## 1 Introduction  
Total hip arthroplasty (THA) is one of the most successful orthopedic procedures with effective results in terms of durability and improvement in the quality of life [1]. However, perioperative periprosthetic femur fracture (PPF) after THA is a rare but devastating complication, with higher rates of morbidity and mortality. Generally, PPFs occur during the surgical implantation of the prosthesis as a consequence of the induced mechanical stress by the stem insertion [2]; moreover, in the majority of the cases, the fracture discovered after some time post-operatively. In [3], it is reported from experimental evidence that the incidence of perioperative prosthetic femur fractures ranges from 0.3 to 27.8% in patients with cemented femoral components, and 2.95% to 27.8% in patients with cementless femoral components, such an incidence being independent on the age or sex of the patients as reported by [PERSON] et al. [4]. Typically, when a cementless stem is implanted, the fracture events occur during femoral canal broaching or implant insertion while trying to obtain a tight press-fit [5]. Cracks in the proximal femur due to press-fit stem implantation are often recognized only after surgery when patients already started to mechanically load their prosthesis [6]. It remains unclear which patient-dependent and/or hospital-dependent factors predispose to PPF after primary THA [7]. Due to the reflections above, and considering the evidence, surgeons usually rely on their experience since they do not have the support of quantitative mechanical measures for their decision-making process [8; 9; 10]. Generally, it reduces to a conservative choosing option: \"older and less-healthy\" patients receive cemented implants while for \"younger and healthier\" are preferred un-cemented prostheses [11]. Although the fracture is a mechanical problem, while the literature is rich of works oriented to reduce the stress levels within the bone during the post-operative life of the implant through different optimization strategies [12; 13; 14; 15; 16], the intra-operative risk of PPF is poorly studied, at least in terms of outcomes to be directly adopted by surgeons. [PERSON] et al. [17] proposed an analytical approach to study the interference fit problem of the femoral stem in cementless THA. [PERSON] et al. [18] proposed a numerical-based patient-specific strategy to estimate the risk of intra-operative PPF. To simulate the actual press-fitting phenomenon (i.e., the interaction between prosthesis and femur), a volumetric expansion of the broach volume was considered, since the female volume inside the femur is smaller than the male volume of the stem. This expansion was obtained by applying a fictitious uniform variation of temperature to the broach nodes. The presented Finite Element (FE) model refers to a patient-specific Computed Tomography (CT) that is labor intensive to create, characterizes the mechanical properties of the femur and evaluates a priori ratios between geometrical and thermo-mechanical parameters [19]. Computational time for meshing, preventing singularities due to the automatic model reconstruction [20] and solving the structural problem can also be extensive. The solutions obtained by computational mechanics are very useful to get scientific insight on the behavior of the implants and to interpret the experimental evidence, but it is rather cumbersome to be used as a light and quick tool for intraoperative assistance to the surgeon's decision. With the aim scope of obtaining a patient-specific evaluation, it is mandatory that the mechanical data, concerning bone density and shape could be inputted in a straightforward way. Moreover, it is desirable that the analysis is completed in a few minutes. In the present work, a simplified model is solved for evaluating the mechanical stress the bone tissue suffers during hip prosthesis implant. The results were compared to those obtained from Finite Element Method (FEM) analysis by [PERSON] et al. [18].