# A Study on the Femoral Neck-Shaft Angle in an Adult Sample From Andhra Pradesh: Osteological and Radiological Measurements

## TL;DR

This study measures the femoral neck-shaft angle in an adult sample from Andhra Pradesh using osteological and radiological methods, finding significant variations based on side, gender, and age.

## Contribution

The study provides new normative femoral neck-shaft angle values for an adult population in Andhra Pradesh with side-specific, gender-based, and age-related variations.

## Key findings

- Osteological measurements showed a significant difference in mean NSA between left and right femora.
- Radiological measurements revealed significant gender-based differences in NSA for females but not males.
- Age-related variations in NSA were significant across all age groups.

## Abstract

The femoral neck-shaft angle (NSA) is a crucial anatomical parameter that plays a significant role in hip biomechanics, lower limb alignment, and load distribution across the hip joint. Variations in femoral NSA are linked to orthopedic conditions and have implications for surgical planning, prosthetic design, and forensic analysis. This study aimed to assess the femoral NSA in an adult sample from Andhra Pradesh using both osteological and radiological methods and to evaluate its variations based on side, gender, and age.

An observational study was conducted from September to November 2024 at Guntur Medical College in Guntur and Government Medical College in Ongole in Andhra Pradesh, India. The study was conducted using osteological measurements from 113 dry femora (54 left, 59 right) and radiological measurements from 30 standardized anteroposterior digital X-rays of adult subjects aged between 20 and 80 years. Femoral NSA was measured bilaterally using a goniometer and image analysis software. Age- and gender-wise analyses were not possible for osteological measurements. Data were analyzed using IBM SPSS Statistics software, version 26 (IBM Corp., Armonk, NY). Independent t-tests assessed side- and gender-based differences, while one-way ANOVA evaluated age-related variation. Pearson’s correlation was employed to compare measurement methods, with a p-value of less than 0.05 considered statistically significant.

In osteological assessment, the mean NSA was 116.54° ± 7.81° on the left and 119.93° ± 3.85° on the right, with a statistically significant difference (p = 0.0047). In radiological measurements, the NSA was 141.15° ± 6.97° (left) and 137.50° ± 5.72° (right), also significant (p = 0.0307). In the radiological measurement, gender-based analysis showed a significant difference in females (p = 0.0385) but not males (p = 0.376). Age-wise, significant right-to-left NSA differences were observed across all age groups, which were 20 to 40 years (p = 0.039), 41 to 60 years (p = 0.048), and 61 to 80 years (p = 0.041). A positive correlation was observed between the two methods (r = 1.0), indicating measurement consistency.

The study establishes normative femoral NSA values for the adult sample from Andhra Pradesh and highlights significant side-specific, gender-based, and age-related variations. The positive correlation between both methods (limited to bilateral variations) supports their reliability in clinical and anatomical assessments. These findings may offer crucial primary reference data for orthopedic procedures, prosthetic alignment, and regional forensic profiling. Future studies with larger, demographically stratified samples and clinical variables are recommended to refine and validate these observations.