Intertrochanteric femoral fractures are among the most common fragility fractures, and their incidence is expected to increase further because of aging of the global population [1]. These fractures significantly impair patients' activities of daily living (ADL) and quality of life (QOL) and are associated with poor survival outcomes. Despite advances in treatment, the one-year postoperative mortality rate remains high (22 %–29 %) [2].

Intramedullary nails and compression hip screws are commonly used for the surgical treatment of proximal femoral fractures. Intramedullary nails are recommended for unstable fractures because they provide greater mechanical stability [3,4]. Although the materials and designs of implants have improved over the years, implant-related complications due to loss of fixation remain prevalent and are critical factors affecting treatment outcomes [5]. Among these complications, cutout is the most prevalent, accounting for 84 % of fixation failures, with an incidence rate varying between 2 % and 16.5 % [[5], [6], [7]]. Low bone mineral density (BMD) is a significant risk factor for cutout [8,9].

BMD is typically measured using dual-energy X-ray absorptiometry (DXA) or quantitative computed tomography of the spine or proximal femur. BMD is an important factor in the preoperative assessment of fractures and serves as a basis for selecting implants or determining the indications for cement augmentation (CA). However, these preoperative assessments are rarely performed in patients with proximal femoral fractures.

In recent years, Hounsfield units (HU) measured by computed tomography (CT) have been reported to show a strong correlation with BMD measured by DXA, suggesting its potential utility as a screening tool for osteoporosis [[10], [11], [12]]. HU measurements offer the advantage of directly estimating the bone density at any specific site, and several studies have measured HU in the femoral head [[12], [13], [14], [15], [16], [17], [18]]. However, to our knowledge, no studies have investigated methods for measuring HU using images of displaced femoral heads after fractures.

The purpose of this study is to measure HU values in the femoral head using preoperative post-fracture CT images of patients with intertrochanteric femoral fractures. Additionally, we aim to investigate a method that demonstrates a strong correlation with BMD measured by DXA. Specifically, this study proposes a new parameter for preoperative assessment by establishing a highly reproducible, low-error measurement method using images of displaced post-fracture femoral heads.