Generating stability in elderly acetabular fractures-A biomechanical assessment

Area of Science:

• Orthopaedic surgery
• Trauma surgery
• Biomechanical engineering

Background:

• Increasing life expectancy leads to more fragility fractures in the elderly.
• Acetabular fractures in older adults are complex due to comorbidities and reduced bone density.
• Anterior column posterior hemitransverse (ACPHT) fractures are common and often involve femoral head subluxation.

Purpose of the Study:

• To determine the most stable fixation construct for ACPHT acetabular fractures in the elderly population.
• To compare the biomechanical stability of different fixation methods for this fracture pattern.

Main Methods:

• Testing of 3 synthetic hemipelvis fixation groups (N=15) for construct stiffness.
• Measurement of fracture line motion under applied loads using a digital imaging system.
• Comparison of a specialty quadrilateral surface plate, 4 long peri-articular screws, and an 8-hole infrapectineal buttress plate.

Main Results:

• The group utilizing 4 long peri-articular screws demonstrated significantly higher construct stiffness compared to other groups.
• Maximal fracture displacement occurred at the posterior column's transverse fracture line and the quadrilateral surface fragment.
• ANOVA with Tukey's test confirmed the statistical significance of the superior stiffness.

Conclusions:

• The optimal fixation for ACPHT acetabular fractures involves independent lag screws and a pelvic brim plate with long periarticular screws.
• Long periarticular screws maximize posterior column fixation and prevent medialization of the quadrilateral fragment.
• While patient factors may influence screw placement, these screws are crucial for preventing secondary displacement.