Os calcis fractures: analysis of interobserver variability in using Sanders classification

Area of Science:

• Orthopedics
• Radiology
• Trauma Surgery

Background:

• The os calcis (heel bone) is the most frequently fractured tarsal bone.
• The Sanders classification system, developed in 1992, utilizes computed tomography (CT) scans for categorizing calcaneal fractures.
• This system is widely adopted for treatment planning and outcome reporting.

Purpose of the Study:

• To evaluate the interobserver variability of the Sanders classification system for calcaneal fractures.
• To determine the reliability of this widely used classification in clinical practice.

Main Methods:

• A random selection of 30 CT scans of calcaneal fractures from two tertiary care centers over five years.
• Fracture classification by three orthopedic surgeons and one senior orthopedic resident using the Sanders system.
• Statistical analysis using weighted kappa tests to assess interobserver agreement, both with and without subcategories.

Main Results:

• A weighted kappa value of .56 (95% CI: .45-.67) was achieved when including subcategories, indicating moderate agreement.
• When subcategories were combined, the weighted kappa value decreased to .48 (95% CI: 0.37-0.59), still representing moderate agreement.
• The analysis demonstrated moderate reliability among clinicians using the Sanders classification.

Conclusions:

• The Sanders classification system demonstrates moderate interobserver agreement for categorizing calcaneal fractures.
• Despite some variability, the system is considered useful for clinical decision-making and reporting in calcaneal fracture management.
• Further refinement or training may enhance consistency in applying the Sanders classification.