Summary
Locking plate technologies are being developed in order to provide the surgeon with
advantages over previous bone plate systems (both locking and non-locking). Locking
plate systems possess inherent biological advantages in fracture fixation by preserving
the periosteal blood supply, serving as internal fixators. It is important to consider
the strength of each orthopaedic implant as an important selection criterion while
utilizing the reported advantages of locking plate systems to prevent catastrophic
fracture failure. Mechanical testing of orthopaedic implants is a common method used
to provide a surgeon with insight on mechanical capabilities, as well as to form a
standardized method of plate comparison. The purpose of this study was to demonstrate
and to quantify observed differences in the bending strength between the LCP (Limited
Contact Plate), LC-DCP, 3.5 mm Broad LC-DCP (Limited Contact Dynamic Compression Plate),
and SOP (String of Pearls) orthopaedic bone plates. The study design followed the
ASTM standard test method for static bending properties of metallic bone plates, which
is designed to measure mechanical properties of bone plates subjected to bending,
the most common loading encountered in vivo. Single cycle four point bending was performed
on each orthopaedic implant. The area moment of inertia, bending stiffness, bending
strength, and bending structural stiffness were calculated for each implant. The results
of this study demonstrated significant differences (p<0.001) in bending strength and
stiffness between the four orthopaedic implants (3.5 Broad LC-DCP>SOP>LCP=LC-DCP).
The 3.5 mm LCP should be expected to provide in vivo strength and stiffness similar
to a comparable LC-DCP. The SOP should provide strength and stiffness that is greater
than a comparable LC-DCP but less than a 3.5 mm Broad LC-DCP.
Keywords
Mechanical testing - SOP - LCP - LC-DCP
