Reliability of Fifth Metatarsal Base Fracture Classifications and Current Management.

Area of Science:

• Orthopedic surgery
• Foot and ankle trauma
• Radiographic classification systems

Background:

• Fifth metatarsal base fractures have historically confusing classifications since 1902.
• Previous zone classifications lacked reliability evaluation.
• Current metaphyseal vs. meta-diaphyseal classification may not be widely known.

Purpose of the Study:

• Evaluate the reliability of the American Orthopaedic Foot & Ankle Society (AOFAS) members in classifying fifth metatarsal base fractures.
• Assess the current management practices for these fractures among AOFAS members.

Main Methods:

• A survey with radiographs of 18 fifth metatarsal base fractures was emailed to AOFAS members.
• Interrater and intrarater reliability were assessed for Jones fracture presence, zone classification, and metaphyseal/meta-diaphyseal classification using Fleiss kappa.
• Respondents reported classification usage and treatment of specific fracture zones.

Main Results:

• 223 AOFAS members completed the initial survey; 80 repeated it for intrarater reliability.
• Interrater reliability was moderate for Jones and zone classifications, but substantial for the 2-zone metaphyseal/meta-diaphyseal system.
• Median intrarater reliability (kappa) was high (0.75-0.78) for all classifications.
• 70% of surgeons treat zones 2 and 3 similarly; ~60% consider acute symptomatic Jones, zone 2, or zone 3 fractures operative.

Conclusions:

• A 2-zone classification system demonstrates high reliability for fifth metatarsal base fractures.
• Given its reliability and surgeon treatment patterns, the 2-zone system is recommended.
• Standardizing classification can improve communication and management of these fractures.