Mechanical testing of 3.5 mm locking and non-locking bone plates

Area of Science:

• Orthopaedic biomechanics
• Biomaterials science
• Surgical implant technology

Background:

• Locking plate systems offer biological advantages in fracture fixation by preserving periosteal blood supply.
• Assessing the mechanical strength of orthopaedic implants is crucial for preventing catastrophic failures.
• Mechanical testing provides standardized comparisons of bone plate performance.

Purpose of the Study:

• To quantify and compare the bending strength of four different orthopaedic bone plates: LCP (Limited Contact Plate), LC-DCP (Limited Contact Dynamic Compression Plate), 3.5 mm Broad LC-DCP, and SOP (String of Pearls).
• To evaluate the mechanical properties of these implants under static bending conditions, simulating in vivo loading.

Main Methods:

• The study followed ASTM standard test methods for static bending properties of metallic bone plates.
• Single cycle four-point bending tests were performed on each type of bone plate.
• Calculations included area moment of inertia, bending stiffness, bending strength, and bending structural stiffness.

Main Results:

• Significant differences (p<0.001) in bending strength and stiffness were observed among the four implants.
• The bending strength and stiffness order was determined as: 3.5 mm Broad LC-DCP > SOP > LCP = LC-DCP.
• The 3.5 mm LCP demonstrated comparable strength and stiffness to the LC-DCP, while the SOP offered intermediate performance.

Conclusions:

• The 3.5 mm Broad LC-DCP exhibits superior mechanical properties for fracture fixation.
• Surgeons can anticipate similar in vivo performance between 3.5 mm LCP and LC-DCP plates.
• The SOP plate provides a mechanical profile between the LC-DCP and the 3.5 mm Broad LC-DCP, offering a distinct option for orthopaedic applications.