1 Principles topenlarge
By definition, type A fractures have no involvement of the articular surface, so accurate reduction of the joint is not required. However, A2 fractures have a metaphyseal wedge fragment. Either absolute stability with ORIF or relative stability with a MIPO bridge plate can be considered.
Whether or not surgery should be done in one stage or multiple stages depends upon the soft-tissue conditions.
Type A fractures with minimal, closed soft-tissue injury
(Tscherne classification, closed fracture grade 0, rarely grade 1)
These injuries may be reduced and fixed primarily, as a single stage procedure, if the soft tissues are in truly excellent condition. A distractor or external fixator may aid reduction. Fibular reduction and fixation is the usual next step, but this reduction must be accurate, so that it does not prevent tibial reduction. Finally, the tibial plate is introduced with MIPO technique and final reduction of length, alignment and rotation is achieved.
Grossly displaced fractures and/or fractures with severe, closed soft-tissue injury
(Tscherne classification, closed fracture grade 2 or 3)
It is generally advisable to proceed in two or more stages:
- Closed reduction and joint bridging external fixation
- Definitive reconstruction after 5-10 days (wait for the apppearance of skin wrinkles)
Open type A distal tibial fractures
These are very severe injuries which may require plastic surgery for soft-tissue reconstruction. The management includes several stages:
- Emergency management: Wound debridement and lavage. Joint-bridging external fixation and stabilization of the fibula (if needed and soft tissues allow). Where possible, closure or coverage of any opening into the joint should be achieved.
- After 48 hours: Soft-tissue coverage (local or free flap). Plan for definitive stabilization at this time.
- Definitive stabilization: Direct reduction and absolute stability with plate and lag screw fixation
Sequence of bone stabilization - fibula or tibia first?
In 43-A2 fractures, the fibula may be fractured as well and needs to be stabilized.
For simple fibular fractures, this is usually done first with ORIF and stable plate fixation. Alternatively, for transverse fractures, consider a small diameter, flexible intramedullary nail. Fibular reduction helps realign the tibia fracture. The operation is completed by stable plate fixation of the tibia. Finally, bone grafting is performed if required.
Some fibular fractures are complex and reduction may be difficult. Their fixation will impede reconstruction of the tibia. In this situation, fibular ORIF is better after the tibia has been fixed. The syndesmotic ligaments are usually intact, so gross realignment of the fibula occurs with reduction and fixation of the tibia. An option, which is attractive for comminuted fibular fractures, is to use a MIPO technique with a long bridging plate, or intramedullary fixation of the fibula with a small diameter, flexible nail. Fibular nailing is particularly applicable if the soft-tissue injury or complexity of the fracture makes extensive exposure for internal fixation hazardous.
Planning of reduction and fixation
Preoperative planning is an essential part of treatment of all distal tibial fractures. It consists of:
- Careful study of the x-rays and CT scan
- Drawing of both the fracture fragments and the desired end result
- Consideration of intraoperative reduction techniques
- Choice of implants
Type A fractures can often be reduced by ligamentotaxis alone with indirect manipulation. A precise anatomical reduction is required for absolute stability. This may require open reduction. If bridge plating and relative stability are chosen, the reduction of this extraarticular fracture is somewhat less critical, but better reduction may still be beneficial if soft-tissue attachments can be preserved.
2 Reduction topenlarge
Indirect reduction with a distractor
An appropriately positioned “femoral” distractor or external fixator is a very helpful tool for reduction. Where possible this should be positioned on the medial side of the leg. Distraction can be used for the open reduction and plate fixation of the fibula as first step (in case of simple fracture pattern of the fibula) and for the reduction of the tibia.
Schanz screws are positioned in safe zones of the tibial shaft and talar neck (or the calcaneal tuberosity). In case of previously applied joint-bridging fixator, the already existing Schanz screws can be used.
Once the fracture has been exposed, taking care to preserve soft-tissue attachments, the fracture can be reduced anatomically.
Incarcerated or displaced fragments can usually be reduced directly. Pointed reduction clamps, dental picks, small Hohmann retractors, or joysticks are some of the instruments available.
Provisional fixation with K-wires is usually required. They should be placed to avoid the plate. See also assessment of reduction.
3 Implant choice and plate preparation top
A variety of precontoured distal tibial plates are available. If such implants are not available, it is important to precontour the plate prior to insertion.
The plate must be chosen long enough to place at least four holes proximal to the fracture (with screws in at least three of them) and distally as much fixation as possible. A small or large fragment plate, or contoured periarticular plate is chosen based on patient size.
If locking head screws must be perpendicular to the plate, their orientation in the distal segment may not be satisfactory. Thus, conventional screws may be better in at least some distal plate holes.
A non-contoured plate can be shaped prior to sterilisation, using a sawbone model as a template. First, determine the length of the plate from preoperative x-rays. Remember that the plate must be twisted to fit the distal tibia. As illustrated, the medial tibia distally lies closer to the sagittal plane while the shaft rotates externally above the metaphysis.
With ORIF of A2 distal tibia fractures, enough of the tibial surface may be exposed to aid and assess plate contouring.
4 Plate insertion and provisional stabilization topenlarge
Insertion of the plate
Insert the prepared plate. Depending on the fracture situation, the plate is usually positioned on the anteromedial aspect, or seldom, on the anterior crest of the tibia. If possible, the plate should be positioned so that the fracture can be lagged with screws passing through the plate. Occasionally it is necessary to insert the lag screws prior to plate application.
It is often possible to pass the proximal end of the plate in a minimally invasive fashion and insert the screws percutaneously at the end of the procedure.
Provisional plate stabilization
Once accurate reduction has been confirmed, a conventional screw can be inserted to provide initial plate stabilization and confirm satisfactory contouring (see assessment of reduction).
5 Applying interfragmentary compression topenlarge
Most larger butterfly fragments are suitable for reduction and stabilization with lag screw(s). Usually two screws are required. The goal is to achieve perfect reduction and compression with a lag screw either through the plate, or separate to it.
Screw placement and direction are important. Avoid the ends of the wedge fragment. Aim each lag screw perpendicular to the fracture plane. Use fully threaded screws with overdrilled glide holes. For more detail, see lag screw principles.
6 Finish fixation topenlarge
Definitive plate fixation
Further proximal and distal screw insertion is completed. The number and position of the screws is dependent on the individual fracture pattern. Ideally, the concept of “balanced” fixation should be achieved with an equal number of screws on either side of the fracture.
Place screws in at least three of the four (minimum) proximal holes, including the most proximal. The chosen distal tibial plate should allow placement of at least three or four screws distal to the fracture.
Close the wound in layers over the plate and fracture. Skin sutures alone are sufficient for proximal screw incisions. A suction drain is optional.
X-rays at the end of the operation confirm the anatomic reduction and fixation of the fracture.