Radiographic study on the anatomical characteristics of the proximal femur in Brazilian adults

Development of Local Software for Automatic Measurement of Geometric Parameters in the Proximal Femur Using a Combination of a Deep Learning Approach and an Active Shape Model on X-ray Images

Proximal femur geometry is an important risk factor for diagnosing and predicting hip and femur injuries. Hence, the development of an automated approach for measuring these parameters could help physicians with the early identification of hip and femur ailments. This paper presents a technique that combines the active shape model (ASM) and deep learning methodologies. First, the femur boundary is extracted by a deep learning neural network. Then, the femur's anatomical landmarks are fitted to the extracted border using the ASM method. Finally, the geometric parameters of the proximal femur, including femur neck axis length (FNAL), femur head diameter (FHD), femur neck width (FNW), shaft width (SW), neck shaft angle (NSA), and alpha angle (AA), are calculated by measuring the distances and angles between the landmarks. The dataset of hip radiographic images consisted of 428 images, with 208 men and 220 women. These images were split into training and testing sets for analysis. The deep learning network and ASM were subsequently trained on the training dataset. In the testing dataset, the automatic measurement of FNAL, FHD, FNW, SW, NSA, and AA parameters resulted in mean errors of 1.19%, 1.46%, 2.28%, 2.43%, 1.95%, and 4.53%, respectively.

CT based measurement of anatomical dimensions of femur and its relevance in nail designs for proximal femoral fractures

Introduction

The purpose of this study was to obtain computed tomography (CT) based measurements of femoral dimensions in adults, to identify its relevance with intramedullary nails used in the management of proximal femur fractures and to suggest a best fitting implant dimensions to our population. To best of our knowledge our study would be first to compile different CT based dimension in single study.

Methods

In our retrospective study of 50 femurs, CT based femoral dimensions measured in standardized cuts and compared with previous studies and commonly available proximal femur intramedullary devices.

Results

68.4 was the mean age in our study, neck shaft angle (NSA) was 127.2±5.2⁰, anteversion 11.2±7.4⁰, endosteal isthmus diameter was 11.9 ± 1.7 mm, anterior radius of curvature (ROC) was 116.8 ± 20 mm, horizontal femoral offset 37.5 ± 4.6 mm, medio-lateral angle 7.8±1.6⁰, with good inter and intra observer correlation. Femoral length and neck width was positively correlated to head diameter, horizontal femoral offset with medio-lateral (ML) angle. One of the 50 femur studied had the parameters in the range of available implant and could match appropriately.

Conclusion

CT based dimensions in our population is different from other population. Based on this study, a design modification of nails used in present day management of proximal femur fractures has been recommended.

Percutaneous medial hemi-epiphysiodesis using a transphyseal screw for caput valgum associated with developmental dysplasia of the hip

Background

The purpose of this study was to evaluate the radiologic outcome of percutaneous medial hemi-epiphysiodesis using a transphyseal screw for the management of caput valgum associated with developmental dysplasia of the hip (DDH).

Methods

Eighteen hips (18 patients) having caput valgum treated with screw hemi-epiphysiodesis were followed for more than 2 years, and were included in this study. The mean age at the time of the index operation was 8.3 years (range, 4.3 to 10.7 years) and age at the latest follow-up was 12.2 years (range, 9.4 to 16.4 years). The screw in 5 hips was changed into a longer one at postoperative 21.8 months (range, 14 to 29 months) because the proximal femur outgrew the screw. The screws in 11 hips were removed at the mean age of 10.9 years (range, 8.0 to 14.5 years). We retrospectively analyzed the change in various radiologic parameters over time.

Results

The mean Hilgenreiner-epiphyseal angle (HEA) of the operated side was 5.1 ± 11.3° preoperatively, and increased to 20.6 ± 11.3° at the latest follow-up (p = 0.001). The mean difference of the HEA between the operated and contralateral sides was 16.9 ± 15.1° preoperatively, which decreased to 2.4 ± 12.4° at the latest follow-up (p = 0.008). The mean articulo-trochanteric distance of the operated side, which was 3.2 ± 5.5 mm longer than that of the contralateral side preoperatively, became 5.6 ± 9.1 mm shorter at the latest follow-up (p = 0.001). The ratio of femoral neck length of the operated side to that of the contralateral side decreased over the follow-up period. Acetabular shape as measured by the Sharp angle and acetabular roof angle and femoral head coverage as measured by lateral center-edge angle did not change significantly by the index operation. The ratio of medial joint space width of the operated side to that of the contralateral side did not change significantly.

Conclusions

Screw medial hemi-epiphysiodesis can effectively correct caput valgum associated with DDH. However, this technique remains coxa brevis and does not seem to significantly affect acetabular morphology or reduce subluxation.