Anatomical Diversity in Femur bones: Understanding the Morphological Variability for Surgical and Prosthetic Applications

The femur, the body's longest bone, plays a critical role in orthopaedics and radiology. Understanding its anatomy, particularly the neck -shaft angle (NSA), is vital for diagnosing bone issues and designing hip implants. While some Asian populations' femur measurements have been studied, there is a research gap concerning Sri Lankans. This study aimed to fill this gap by examining the proximal femur's anatomy in the Sri Lankan population. We analysed 45 adult human femurs (26 right, 19 left) of unknown sex, ethically sourced from the University of Sri Jayewardenepura. Femurs with fractures or pathologies were excluded. Precise measurements were recorded using digital vernier callipers, with millimetre accuracy. Parameters included mean femoral length, vertical and transverse femoral head diameters, neck axis and neck length. Each measurement was taken three times to minimize subjectivity. Right femurs had a mean length of 42.8 mm (SD +/- 2.64), while left femurs measured 43.53 mm (SD +/- 3.27). Mean NSA was 125.78 degrees (SD +/- 4.45) for left femurs and 127.59 degrees (SD +/- 2.06) for right. Mean femoral head diameters were 4.09mm (SD +/- 0.30) (right) and 4.12mm(SD +/- 0.31) (left). Mean anterior neck lengths of the right and left were 2.61(SD +/- 0.54) and 2.71(SD +/- 0.50) respectively. Comparing our findings with other Asian populations highlighted significant variations in femur measurements. These discrepancies emphasize the need for population -specific data for orthopaedic interventions and raise questions about the suitability of imported prosthetics. Differences in femur length, neck length, and NSA between sides suggest potential challenges in using implants designed for one side on the other. This study underscores the necessity of population -specific data in orthopaedics, as femur measurements differ even among Asian populations. Further research and statistical analysis are essential for tailoring orthopaedic solutions to individual populations. The findings also suggest a potential need for locally manufactured prosthetics to better suit the Sri Lankan population.