What is a locking plate?
What is a locking plate?
Locking plates are fracture fixation devices with threaded screw holes, which allow screws to thread to the plate and function as a fixed-angle device 1 – 3. These plates may have a mixture of holes that allow placement of both locking and traditional nonlocking screws (so-called combi plates) 4 , 5.
What is a locking plate used for?
Conventional plate osteosynthesis seeks to obtain maximum stability with a rigid plate and if possible compression of the fracture fragments. Locking plate fixation, on the other hand, seeks to maintain a certain elasticity to stimulate bone healing. Locking plates are generally less rigid than conventional plates.
How does a locking plate work?
A locking plate does not have to precisely contact the underlying bone in all areas. When screws are tightened, they “lock” to the threaded screw holes of the plate, stabilizing the segments without pulling the bone to the plate. Locking screws make it impossible for screw insertion to alter the reduction.
What is locking compression plate?
The locking compression plate is a contemporary implant that allows for both conventional screw placement (using nonlocking screws) and locking screw placement (where screw heads lock into the plate at a predetermined angle). This allows for greater versatility in the application of internal fixation.
Are cortical screws locking?
Periarticular locking plates are commonly used for fixation in distal femur fractures but are associated with a high nonunion rate, likely due to the stiffness of the constructs. Far cortical locking (FCL) screws are designed to allow micromotion at the near cortex while maintaining purchase in only the far cortex.
Whats the difference between locking and non locking screws?
Non-locked screws generate shear stress at the bone-screw interface upon axial loading, and the axial force is countered by a frictional force between the plate and bone. Locking constructs, however, subject the bone-screw interface to compressive forces, by converting shear stress into compression.
What type of screws can be inserted in to locking compression plates?
The Locking Compression Plates have combination locking and compression (Combi™) holes. The Combi holes allow placement of conventional cortex and cancellous bone screws on one side or threaded conical locking screws on the opposite side of each hole.
What is far cortical locking?
Far Cortical Locking can reduce the stiffness of locked plating constructs while retaining construct strength. The Journal of bone and joint surgery. 2009;92 in press. [ Bottlang M, Lesser M, Koerber J, et al. Far cortical locking can improve healing of fractures stabilized with locking plates.
What are lock screws?
Locking screws inserted into the stem of the plate provide an additional point of fracture fixation, prevent screw toggle, and increase plate resistance to axial loads compared with conventional screws, owing to locking screw head thread engagement in corresponding threads within the locking plate hole.
What are locking screws?
What is a 1/3 tubular plate?
Introduction. An inter-fragmentary lag screw protected by a lateral one-third tubular plate is the most commonly used fixation method for treating displaced lateral malleolar fractures. Difficulty achieving adequate screw thread purchase in the cancellous bone of the distal fragment can lead to the screws backing out.
What is an LCP plate?
The Synthes Locking Compression Plate (LCP) is part of a stainless steel and titanium plate and screw system that merges locking screw technology with conventional plating techniques. plating with conventional cortex or cancellous bone screws.
Which is an example of biomechanics of a plate?
• Biomechanics of plates • Plate Types – Compression – Buttress/Antiglide – Bridge – Tension Band – Locking – Internal Fixator – Neutralization Lag screws • Case Examples Biomechanics • Plate is on outside of bone • Materials – Ti • Closer Modulus of Elasticity to bone • Weaker in Shear(screw heads) • Cold Welding – Stainless • Stiffer
Why are screws used to lock a plate?
With the conventional technique, the tightening of the screws presses the plate against the bone. This pressure generates friction, which contributes significantly to primary stability. Loading forces are transmitted from the bone to the plate, across the fracture and back into the bone.
How are loading forces transmitted from bone to plate?
Loading forces are transmitted directly from the bone to the screws, then onto the plate, across the fracture and again through the screws into the bone. Friction between plate and bone is not necessary for stability.
What is the hole in a locking plate?
The locking plate has a corresponding threaded plate hole. During insertion the locking head screw engages and locks into the threaded plate hole. If necessary the threaded plate hole also accepts nonlocking screws, which permit greater angulation.