A 3- or 4 hole Dynamic Compression Plate (DCP) can be used successfully for this procedure. Another alternative represents the 3- and 4 hole Limited Contact Dynamic Compression Plates (LC-DCPs).
The plate is contoured to approximate the dorsal surface of the distal proximal phalanx and proximal middle phalanx. The distal end of the plate is then bend slightly to ensure that the middle phalangeal plate screw is directed just distal to the subchondral plate into the proximal and axial aspect of the middle phalanx.
The plate is held in position by hand, with the help of a bone holding clamp, or as shown here with the large pointed reduction forceps. The use of appropriate imaging technology to check the positioning of the implant and the proposed screw position is strongly encouraged.
The thread hole for the first 5.5mm cortex screw is drilled just distal to the subchondral plate across the entire bone, and the length of the drill hole is determined, and tapped followed by insertion of the selected screw.
A 5.5 mm cortex screw is placed in load position through the middle plate hole. The screw should not be fully tightened, so the plate is not yet fully compressed to the bone and dynamic compression is not engaged.
Insertion of transarticular lag screws
Two 5.5 mm cortex screws are now placed transarticularly in lag fashion extending from the dorsal distal proximal phalanx into the proximal palmar/plantar middle phalanx. They cross the joint at the junction of the palmar/plantar ¼ and the dorsal ¾. The two glide holes are prepared first, but it is important that first one screw hole is finished and the screw inserted before the thread hole for the second screw is prepared. The transarticular screw that is on the side where the palmar/plantar eminence fracture is located, may need to be directed slightly away from the fracture to avoid entering the fracture line. In addition, positioning in the sagittal plane may require modification to avoid the lag screw if one has been used to affix a large eminence fragment to the parent middle phalanx. The screws are placed medial and lateral to the plate and parallel to the sagittal plane.
Real time imaging is useful to direct screw positioning and intraoperative imaging of some nature is necessary to confirm proper implant position.
It is very important that the glide holes for the transarticluar lag screws in the dorsal distal aspect of the proximal phalanx are appropriately countersunk to ensure the screw heads engage the dorsal cortex in an appropriate fashion and thereby avoid bending, weakening and potentially breaking the screw head.
It is also important, that screws of appropriate length are used; they should not penetrate beyond the palmar/plantar cortex of the middle phalanx. For the transarticular lag screws, a screw measuring 4-6 mm less than the measured length is appropriate and prevents placing a screw which protrudes beyond the palmar/plantar cortex of the middle phalanx.
Once the transarticular lag screws are fully tightened, the middle plate screw is fully tightened, which compresses the plate to the bone and provides additional axial compression between the subchondral plates of the proximal phalanx and the middle phalanx.
Insertion of the remaining screw
Finally, the proximal hole of the plate is filled with a unicortical 4.5mm cortex screw.
Confirmation of fixation
The final construct configuration is checked with appropriate imaging to ensure appropriate length and positioning of all implants.