Asian Journal of Orthopaedic Research

The sesamoid bone is a small oval-shaped bone found mostly within the tendons around the surface of joints, e.g. hand, wrist, foot and the knee, which has the biggest and most popular sesamoid bone. During the formation of sesamoid bones, the appearance of cartilaginous nodules undergoes replacement during a prepubertal stage in a process called endochondral ossification, which will metamorphose as sesamoid bone during puberty, though they occur first in female. This study, conducted in Calabar, Cross River State, Nigeria, aimed to evaluate and provide valuable insights into the prevalence and distribution of rare sesamoid bones in the lower extremities among patients who had radiological investigations conducted on them at UCTH and ASI-Ukpo Diagnostic Centre. The study was conducted using an observational, descriptive and cross-sectional study design with a random sampling approach. Inclusion and exclusion criteria were adhered to during data collection.  The result shows that about 70% of the participants exhibit these bones. Asi-Ukpo Medical Centre had a significantly higher prevalence of sesamoid bones (92.3%) compared to UCTH (59.3%). The rare sesamoid bones in the knee were less prevalent. Only a small fraction of participants had sesamoid bones in this area, either bilaterally (12.5%) or unilaterally (10.7%). Symmetrical distribution of rare sesamoid bones was observed in 73.2% of the participants while, Females showed a slightly higher prevalence (70.8%) compared to males (68.85%). The findings from this study are largely and significantly consistent with global data, highlighting the universal patterns in the occurrence of sesamoid bones.