[Total modular hip arthroplasty for fracture in pathological terrain secondary to fibrous dysplasia. Presentation of a clinical case and literature review].

Fibrous dysplasia (FD) is a benign tumor condition in which normal bone is replaced by structurally deficient fibrous lamellar bone. It represents approximately 5-7% of benign bone tumors and occurs in two presentations: monostotic, which is the most common, and polyostotic. The proximal femur is one of the most common locations for benign tumors, including FD. Fractures in pathological terrain are often the first symptom. In the context of a proximal femur fracture with a benign tumor, the indications for carrying out a total femoral resection are: multiple lesions in the femur or primary diaphyseal tumors, lesions that extend proximally and distally to exceed the epimetaphyseal junction area, and those that do not allow the joint to be adequately preserved. Currently, proximal or total femoral resection is considered a good therapeutic option to carry out endoprosthetic replacement using modular megaprosthetic systems. We present the case of a 27-year-old male patient, who came to the emergency department with a basicervical fracture of the right femur in Garden II Pauwells III AO 31B2.3r pathological terrain, after presenting a low-energy injury mechanism characterized by axial loading with rotational component of the right hip. This patient has a history of intralesional resection, application of bone graft and prophylactic fixation using unspecified osteosynthesis material in the pertrochanteric region 20 years ago; the biopsy would later show DF; the osteosynthesis material was subsequently removed one year later. Due to the characteristics of the fracture and as a definitive and curative therapeutic method, it was decided to carry out wide resection of the proximal femur and total hip arthroplasty with a modular prosthesis with cerclage placement, as well as taking an excisional biopsy that would later corroborate that it was the same FD treated in childhood.