Study of Sexual Dimorphism by Femoral Neck Shaft Angle in Eastern U.P.

Background: The femoral neck shaft angle (NSA) is a key anatomical parameter that contributes to hip joint stability, locomotion, and weight-bearing. Variations in NSA are influenced by factors such as age, sex, and ethnicity. Understanding sexual dimorphism in NSA is critical for clinical, forensic, and orthopedic applications, yet limited data exist for the population of Eastern Uttar Pradesh, India. Aim: To study sexual dimorphism in the femoral neck shaft angle among the population of Eastern Uttar Pradesh, focusing on differences between males and females, age-related variations, and implications for clinical and forensic applications. Methods: This retrospective and prospective observational study included 300 participants (150 males and 150 females) aged 20–45 years. Standardized antero-posterior pelvic radiographs in the supine position with 15–30° internal rotation were analyzed. NSA measurements were obtained using RadiAnt DICOM Viewer software. Descriptive and inferential statistical analysis, including independent and paired t-tests, were performed using SPSS version 25.0. Results: Males exhibited significantly higher mean NSA values (134.53° ± 4.97°) compared to females (129.63° ± 5.06°, p < 0.001). Minimal side-to-side differences in NSA were observed within each gender. NSA values showed an age-related decline in both sexes, but males consistently exhibited higher values across all age groups. Conclusion: This study confirmed significant sexual dimorphism in NSA, with males having consistently higher values than females. Age-related reductions in NSA were noted, yet sexual dimorphism persisted across age groups. These findings have important clinical and forensic implications, particularly in sex determination and orthopedic implant design. Recommendations: Future research should expand to larger and more diverse populations to validate these findings. Additionally, studies investigating the relationship between NSA and other anthropometric and biomechanical parameters are recommended to enhance clinical and forensic applications.