Comparison of Titanium and Bioresorbable Plates in "A" Shape Plate Properties-Finite Element Analysis

Area of Science:

• Orthopedic surgery
• Biomaterials science
• Biomechanics

Background:

• Traditional rigid fracture fixation can leave permanent materials after healing.
• Resorbable plates offer a solution to avoid complications from retained hardware.
• This study evaluates bioresorbable plates against traditional titanium plates for condylar fractures.

Purpose of the Study:

• To compare the biomechanical performance of bioresorbable polylactic acid (PLLA) and titanium "A" shape condyle plates in treating condylar fractures.
• To analyze stress distribution and bone-plate interaction under simulated fracture conditions.

Main Methods:

• Finite element analysis was employed to model a high right condylar neck fracture.
• Both 1.0 mm thick PLLA and titanium "A" shape plates (31 mm height, 19 mm width) with specific dimensions and hole configurations were simulated.
• Stress concentrations on bone surfaces and screws were evaluated for both materials.

Main Results:

• The highest stress on the bone surface was observed on the anterior bridge around the first screw hole, approximately 100 MPa.
• Maximum stress on the screws was highest in the anterior bridge, with titanium experiencing greater stress (150 MPa) than PLLA (114 MPa).
• PLLA fixation resulted in approximately double the bone surface pressure compared to titanium.

Conclusions:

• PLLA osteosynthesis exerts significantly higher pressure on the bone surface than titanium fixation.
• Excessive localized bone pressure can lead to bone degradation, potentially impeding or preventing fracture healing.
• The flexibility of PLLA fixation may cause bone edge sliding and twisting, contributing to callus degradation and compromising healing outcomes.