A radiological classification system for talocalcaneal coalition based on a multi-planar imaging study using CT and...

Area of Science:

• Orthopedic imaging
• Foot and ankle anatomy
• Radiological classification systems

Background:

• Talocalcaneal coalition is a congenital condition affecting the foot and ankle.
• Existing classification systems may not adequately describe the spectrum of talocalcaneal coalition.
• A standardized radiological approach is needed for adult talocalcaneal coalition.

Purpose of the Study:

• To develop a novel radiological classification system for adult talocalcaneal coalition.
• To categorize talocalcaneal coalitions based on imaging characteristics.
• To determine the prevalence of different coalition types.

Main Methods:

• Retrospective review of 70 feet (59 patients) diagnosed with talocalcaneal coalition.
• Classification based on cartilaginous/bony nature, facet joint orientation, and bony morphology.
• Utilized computed tomography (CT) and magnetic resonance imaging (MRI) with multi-planar reformation.

Main Results:

• A four-type classification system (I-IV) was developed: Type I (linear), Type II (talar overgrowth), Type III (calcaneal overgrowth), and Type IV (complete osseous).
• Type I was most common (64%), followed by Type III (19%), Type II (14%), and Type IV (3%).
• Fracture fragments were observed in 16 feet, predominantly from the calcaneus in Type I and III coalitions.

Conclusions:

• A new radiological classification system for talocalcaneal coalition in adults has been established.
• The system effectively categorizes coalitions based on multi-planar imaging findings.
• The study determined the relative frequencies of coalition types and identified common origins of fracture fragments.