As the locking compression plate is suitable for MIPO, it is also possible to perform it by using standard screws. The use of conventional plates such as limited contact dynamic compression plate and dynamic compression plate along with the fixed condylar screws. For the successful application, while performing such conventional MIPO Implants special precautions are needed to be taken.
Majorly with the complex fracture, the bridging plate mode is used despite the use of locking compression or conventional plate in MIPO. Stress concentration and long plates are required to avoid any kind of irregularities while placing holes for screw one and screw two away from the site of fracture. Relative stability is provided with this kind of fixation although it can also impair somehow with the flexibility degree. With the formation of callus, the healing of fractured bones is promoted which is fast and reliable in comparison to primary bone healing. In the case of multifragmentary fractures, it can prove to be helpful.
Implants for MIPO:
There are different types of Implants with which the MIPO can be performed like,
- Locking plates like LISS and LCP
- conventional plates like straight plates, DCP, and LC-DCP.
- Fixed angle Implants like DCS or condylar plates.
Guidelines for use of Implants for MIPO:
There are certain guidelines which needs to be followed while performing MIPO,
Locking compression plate (LCP):
By using indirect methods at first the fracture needs to be reduced if necessary, after it with the help of external fixators or distractors the reduction is maintained. The Ortho Implants can also be used for the reduction of the plate is pre-shaped or well countered. The LCPs compression function is used like in case of simple transverse fracture, the plates are first countered accurately and then axial compression is done with the help of standard screws. It needs to be remembered that the holes of LCP are arranged asymmetrically. The unidirectional exertion of dynamic compression is allowed due to this asymmetric arrangement. The exertion with standard screws is done after the axial compression. In the case of simple or spiral oblique fractures, if it is required then interfragmentary compression is also allowed. Before LHS application the standard screws as lag screws are accomplished. With the help of a universal drill guide, the screws can be inserted. The depth of pre-drilled screw holes is examined, measured, and tapped for the appropriate insertion of standard screws. By using the bending instruments the contouring of plates can be done if required. The bending should not be performed through the holes, it should be between the combination of the hole so that hole deformity is prevented.
The insertion of threaded drill sleeve or the LHS into the combination hole is also another way to prevent deformity, before performing the bending. To ensure the gap of 2mm the LCP space can also be screwed before the insertion this reduces the contact between the plate and bone resulting in the preservation of periosteal circulation. After LHS insertion space can also be removed.
The skin incisions are also created which are corresponding to the plate position. For creating the submuscular extra periosteal plate tunnel a tunneler is used. Through this tunnel, the plate is allowed to pass. In the case of a tunneler, the plate end is tied with suture to the tunneler end. With the withdrawal of the tunneler the position of the plate is maintained. The one end of the plate is fixed with the plate holder or with the threaded LCP drill guide which later places the plate into position. Screw insertion can be done after placing the plate. Temporary stabilization of the plate is required either with K wire or any other thing if the first screw is inserted in LHS. This prevents the rotating of plate or helicopter effect as it can result in the damaging of the surrounding soft tissues. After locking the first LHS the quality check is done to assure the fracture reduction and then rest LHS are inserted.
A stab incision is made in the skin through which the threaded Locking compression plate drill guide is introduced for inserting the self-tapping LHS pre-cutaneously. The drill guide helps in ensuring the right direction of the drill so that the screws can be locked correctly with maximum angular stability. The screw hole is later measured and drilled, after it the insertion of LHS is done by the help of a power tool along with the screwdriver shaft and then final tightening is done. In the case of self tapped and self drilled LHS there is no requirement for depth measurement and pre-drilling.
There is a special guiding block that fits the Epiphyseal plate end that can provide accurate and easy mounting when the LCP is pre-shaped anatomically. It is done to ensure the correct drilling. Without the removal of a guiding block, the insertion of appropriate LHS can be done after pre-drilling which is followed by the removal of threaded LCP guide. In required cases, the indirect fracture reduction can also be achieved with the help of a screw holding sleeve to cover the head of LHS. The pulling of the underlying bone towards the plate can occur while tightening the screw. The standard screws needed to be inserted first if both LHS and standard bone screws are used in the same construct.