Dynamic plate osteosynthesis for fracture stabilization: how to do it

Abstract

Plate osteosynthesis is one treatment option for the stabilization of long bones. It is widely accepted to achieve bone healing with a dynamic and biological fixation where the perfusion of the bone is left intact and micromotion at the fracture gap is allowed. The indications for a dynamic plate osteosynthesis include distal tibial and femoral fractures, some midshaft fractures, and adolescent tibial and femoral fractures with not fully closed growth plates. Although many lower limb shaft fractures are managed successfully with intramedullary nails, there are some important advantages of open-reduction-and-plate fixation: the risk of malalignment, anterior knee pain, or nonunion seems to be lower. The surgeon performing a plate osteosynthesis has the possibility to influence fixation strength and micromotion at the fracture gap. Long plates and oblique screws at the plate ends increase fixation strength. However, the number of screws does influence stiffness and stability. Lag screws and screws close to the fracture site reduce micromotion dramatically.DYNAMIC PLATE OSTEOSYNTHESIS CAN BE ACHIEVED BY APPLYING SOME SIMPLE RULES: long plates with only a few screws should be used. Oblique screws at the plate ends increase the pullout strength. Two or three holes at the fracture site should be omitted. Lag screws, especially through the plate, must be avoided whenever possible. Compression is not required. Locking plates are recommended only in fractures close to the joint. When respecting these basic concepts, dynamic plate osteosynthesis is a safe procedure with a high healing and a low complication rate.

Keywords: bone healing; dynamic osteosynthesis; fracture stabilization; plate fixation..

Figure 1

Rigid plate osteosynthesis of the femur. All fracture fragments are anatomically reduced. Many screws and lag screws are used. No callus formation is observed.

Figure 2

Biological plate osteosynthesis. Preoperative (left) and postoperative (right) radiographs of a comminuted femoral fracture are shown. There are only a limited number of screws. Lag screws and screws in the fracture area are avoided. The unicortical screw in the middle serves to hold one big fragment in place.

Figure 3

Two different patterns of fracture healing: in osteonal fracture healing the fracture gap is bridged by osteones. In non-osteonal fracture healing the fracture gap is bridged by callus.

Figure 4

Secondary osteonal fracture healing. First, callus formation is observed followed by osteone migration. The fracture fragments are in direct contact (secondary contact healing, left) or separated by only a small fracture gap (secondary gap healing, right).

Figure 5

Influence of bridging length on fracture motion: micromotion at the fracture gap increases exponentially with increasing distance of the screws from the fracture site.

Figure 6

Example of a dynamic plate osteosynthesis in a distal tibial fracture. Preoperative (left), postoperative (middle), and radiographs after fracture healing (right) are shown. A long plate with a limited number of screws is used. Screws close to the fracture site and lag screws are avoided.

Figure 7

Plate failure: postoperative radiographs (left), at six weeks (middle), and after revision surgery (right). Note that the principles of dynamic plate osteosynthesis were not respected during the primary procedure by inserting a lag screw through the plate. Plate breakage was recorded at six weeks. Fracture healing was achieved after revision surgery with replacement of the plate, additional osteosynthesis of the fibula to provide lateral support, and removal of the lag screw to allow micromotion.