Calcaneus fracture pattern and severity: Role of local trabecular bone density

Area of Science:

• Orthopedics
• Biomechanics
• Forensic Science

Background:

• Calcaneus fractures are the most common tarsal bone injuries, often resulting from high-energy impacts like vehicle accidents or sports.
• Surgical fixation of the calcaneus is complex due to its significant weight-bearing role (nearly 50% of foot load).

Purpose of the Study:

• To investigate the relationship between regional trabecular bone mineral density (BMD) of the calcaneus and fracture patterns.
• To determine if regional BMD differences predict calcaneal fracture severity and location.

Main Methods:

• Postmortem human subjects (n=14) were analyzed using Quantitative Computed Tomography (QCT) to measure regional trabecular BMD in anterior and posterior calcaneus.
• Existing tolerance data and fracture patterns from previous tests on the same specimens were utilized.
• Statistical analysis was performed to assess the significance of BMD values and ratios in relation to fracture outcomes.

Main Results:

• The posterior calcaneus exhibited higher mean BMD (114 mg/cc) compared to the anterior region (81 mg/cc).
• Specimens with axial loading showed a higher incidence of severe anterior calcaneal fractures (50%) versus low-severity posterior fractures (36%).
• A significant BMD ratio difference (p=0.02) was found between anterior and posterior regions in fractured specimens, with anterior fractures being more severe (intraarticular/crush).

Conclusions:

• Regional variations in calcaneal trabecular BMD are significant, with the anterior region being less dense.
• The disparity in BMD between the anterior and posterior calcaneus may be a more critical predictor of fracture severity than absolute BMD values.
• These findings offer insights into calcaneal injury mechanisms and could inform fracture risk assessment.