bone plates

The Locking Compression plates are used for fractures that are stable in compression. They may be used in combination with lag screws, and they may offer dynamic compression when used on the tension side of bone. the dynamic compression plate is one of the most common types of bone plates and can be recognized by its special oval screw holes. These holes have a special beveled floor to them with a surface that is inclined. If desired, this inclined surface can be used to pull ends of the bone together as the bone screws are tightened. These plates are provided by Orthopedic products manufacturers from Indonesia.

Dynamic compression plate (DCP) bridging a fibular fracture the arrow is pointing to a syndesmosis screw which is bridging tibiofibular syndesmosis, whose ligaments have been torn during the injury- also noted is a medial malleolar fracture bridged by a channel of the screw, but apparently little else. What is holding the areas of this fracture together?

The medial malleolar fracture above is held together by one of these screws, made of a radiolucent polycarbonate material, which is intended to ultimately be absorbed by the body- this type of screw is known as “stealth hardware”.

A new variety of dynamic compression plate is now undergoing trials at UW. The variant is called a LCDC (low contact dynamic compression plate) plate. This plate is distinguished from the conventional DCP by the way it is undercut each screw hole and between adjacent holes of the screw. The rationale for this design is as follows. Whenever one clamps a plate down against the bone surface, one markedly diminishes the periosteal blood supply to that area. Theoretically, one would expect this to slow fracture healing beneath that bone plate. The undercutting of the plate reduces the amount of contact that the plate makes with the bone surface, and hopefully will increase the periosteal blood supply as well as fracture healing is expected.

Another type of plate seen commonly at UW is the reconstruction plate, which is widely used for the repair of calcaneal and pelvic fractures. This plate is malleable and can be readily trimmed and shaped to length for support of fractures through complex bony surfaces. These are also sometimes used for posterior fusion of the cervical spine.

Neutralization plates are designed to protect fracture surfaces from the normal rotation, bending and axial loading forces. Buttress plates are used to support bone that is unstable in axial or compression loading. These plates are often used in the tibial plateau and distal radius to hold depressed and impacted fragments in position once they have been elevated.

Yet another kind of plate commonly seen on postoperative films is the blade plate. This plate is generally shaped at a right or oblique angle and is designed to be used with supracondylar fractures of the femur or subtrochanteric femoral fractures. It is also sometimes used to bridge a femoral osteotomy. The other arm is used as a side plate and anchored to the bone with several screws.

There are different devices used to treat femoral fractures. The plate above and the Jewett nail below are not used so commonly these days, but patients still walk into orthopedic clinic wearing these devices every day. The most common device used currently is the dynamic hip screw. its main design goals are to resist angular deformation while allowing early fracture impaction by permitting shortening along the axis of the lag screw. this device is specifically designed to treat intertrochanteric fractures, but is sometimes used to treat subtrochanteric fractures as well. Like the blade plate, it has a side plate that is attached to the distal femur with numerous cortical screws. rather than a blade, this plate has a hollow metal barrel through which a big lag screw is placed.

This big lag screw is placed so that it bridges the femoral fracture. Ideally, this lag screw should go right down the center of the femoral neck on every radiographic view, and its tip should be in the subchondral bone of the femoral head. The hollow barrel of the side plate holds the lag screw, and so the femoral head and neck at an anatomic angle for healing. It also allows the lag screw to slide distally as the ends of the fracture impact and fragments of fracture move closer together. The average impaction amount seen with these devices is about 7 mm. The various screws that are talked about are all the orthopedic implants. Dynamic hip screw (DHS) is a common device used to bridge fractures of the well-vascularized intertrochanteric area. But when the fracture occurs a bit more proximally in the femoral neck, parallel screw fixation is often used instead. The rationale here is that the parallel screws will cause less trauma to the tenuously supplied neck and fragment and proximal head than a larger screw such as the DHS. If the bone screws are placed parallel to each other, they can allow the bone fragments to impact together, much as a DHS will. Knowles pins, (shown below) were once commonly used for this purpose, although other types of bone screws are more commonly used today.


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