Radiographic Morphologic Characteristics of Bunionette Deformity

Area of Science:

• Orthopedic surgery
• Radiographic imaging
• Foot biomechanics

Background:

• Bunionette deformity is characterized by fifth metatarsal abnormalities.
• Previous research has primarily focused on the fourth and fifth metatarsals.
• Limited studies have analyzed the radiographic morphology of the entire foot in bunionette cases.

Purpose of the Study:

• To analyze the radiographic morphologic characteristics of the entire foot in symptomatic bunionette deformity.
• To compare foot morphology between individuals with and without bunionette deformity.
• To identify potential new classifications or contributing factors to bunionette deformity.

Main Methods:

• Utilized a radiographic image-mapping system for morphologic analysis.
• Analyzed 112 feet with symptomatic bunionette deformity and 123 asymptomatic control feet.
• Compared foot morphologies using 2D coordinates, angle measurements, and categorized cases according to Fallat's system, including a new type V deformity.

Main Results:

• Feet with bunionette deformity showed greater lateral displacement of the third, fourth, and fifth metatarsal heads and increased intermetatarsal angles.
• The morphology of the fifth metatarsal alone may not be the sole cause of bunionette deformity.
• Specific intermetatarsal angle increases were observed in different deformity types (II, III, IV, and V) compared to controls.

Conclusions:

• Surgical planning for bunionette deformity requires assessment of the entire foot's morphology, not just the fourth and fifth metatarsals.
• Forefoot width and metatarsal splaying across all metatarsals are important considerations.
• A comprehensive radiographic evaluation aids in understanding and managing bunionette deformity effectively.