[Radiologic study on postnatal ossification of the first metatarsal bone]

Area of Science:

• Orthopedics
• Anatomy
• Pediatric Radiology

Background:

• Classical descriptions of first metatarsal ossification note a single proximal nucleus.
• Recent studies suggest a second, distal ossification nucleus, debated as epiphysis or pseudoepiphysis.
• Understanding this distal nucleus is crucial for accurate anatomical descriptions.

Purpose of the Study:

• Determine the prevalence of the distal ossification nucleus of the first metatarsal bone.
• Investigate its role in the longitudinal growth of the first metatarsal.
• Analyze its association with qualitative variables like foot type and flat foot.

Main Methods:

• Retrospective analysis of 971 dorsoplantar radiographic images from 225 patients.
• Evaluation of the presence, age of appearance/closure, and growth contribution of the distal nucleus.
• Correlation with qualitative variables including foot morphology and type.

Main Results:

• The distal ossification nucleus was observed in 40% of images, with 81.1% prevalence in ages 4-7 years.
• Mean age of appearance was 3.07 years, and mean physeal closure was 7.67 years.
• A greater definitive length of the first metatarsal bone was associated with the presence of this distal nucleus.

Conclusions:

• The distal ossification nucleus of the first metatarsal bone is a distinct entity.
• This nucleus functions as a growth cartilage, influencing the final length of the first metatarsal.
• Its presence is linked to specific foot types and may impact longitudinal bone growth.