Executive Editor: Peter Trafton

Authors: Martin Hessmann, Sean Nork, Christoph Sommer, Bruce Twaddle

Distal tibia 43-A3 MIPO

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Glossary

1 General considerations top

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General principles of Management

Type A3.3 fractures are extraarticular complex fractures which extend from metaphysis into the tibial shaft. By definition, type A fractures have no involvement of the articular surface, so accurate reduction of the joint is not required. The soft-tissue conditions usually dictate the choice of procedure: early single-stage or multiple-stage surgery. The decision is based on the individual situation and not necessarily on general principles. The associated shaft involvement requires a longer, stronger plate. This type of fracture lends itself to MIPO type stabilization because of the minimum insult to the soft-tissue envelope.


Displaced 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 help 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.


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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:

  1. Closed reduction and joint bridging external fixation
  2. Definitive MIPO reconstruction after 5-10 days (wait for the apppearance of skin wrinkles)

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Open distal tibial fractures

These are very severe injuries which may require plastic surgery for soft-tissue reconstruction. The management includes several stages:

  1. 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.
  2. After 48 hours: Soft-tissue coverage (local or free flap). Plan for definitive stabilization at this time.
  3. Definitive stabilization: Bridging of the metaphyseal comminution, with or without bone graft.

Bone grafting at the time of soft-tissue coverage is possible if the envelope is obviously viable but in marginal soft-tissue situations or in the multi-traumatized catabolic patient bone grafting as a secondary procedure may be advisable.

2 Planning for reduction and fixation top

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Fibula or tibia first? Sequence of bone stabilization

In most type 43-A3 fractures, the fibula is 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 anatomic bridging fibular 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.


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Planning for 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 (often indicated by a reversed tracing of the intact opposite tibia)
  • Consideration of intraoperative reduction techniques
  • Choice of implants

Type A (extraarticular) fractures can often be reduced by ligamentotaxis alone with indirect manipulation. Direct exposure is therefore not often necessary. The shape of the implant serves as a reduction tool. A properly contoured plate applied according to a good preoperative plan improves your chances of a good reduction.

3 Implant choice and plate preparation top

Implant choice

Because 43-A3.3 fractures involve the tibial diaphysis, a longer and stronger plate is usually necessary. A variety of precontoured distal tibial plates are available. If such an implant is not available, or is insufficient for the fracture proximally, it will be necessary to precontour a standard (4.5 or 3.5 mm) plate prior to insertion. With MIPO plate constructs it is preferable to choose as long an implant as possible for the widest distribution of load at the fracture site. Choose a plate that allows enough screws to be placed in the distal fragment.


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Plate contouring

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.

4 Preliminary reduction top

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Indirect reduction with a distractor

An appropriately positioned large 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.

Final reduction depends upon bringing the proximal and distal tibial segments into proper position against a correctly contoured plate. Non-locked screws or a push-pull reduction devices can be used to approximate the bone to the plate.

5 Plate insertion top

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Plate insertion

The plate is now inserted after proximal tunneling with a blunt instrument.

Depending on the fracture situation, the plate is usually positioned on the anteromedial aspect of the tibia.

6 Plate fixation top

Preliminary plate stabilization

Temporary fixation can be performed with K-wires through the screw holes (or inserted drill sleeves) to check the final plate position before the first screw is inserted.

Once accurate restoration of length, alignment and rotation have been achieved, provisional stabilization of the plate can be performed with a single conventional “positioning” screw inserted through the plate. If this is achieved with the most proximal screw, it is advisable to formally expose the proximal end of the plate.

Next, reduction is finalized by pulling the distal segment against the plate with a non-locking screw or other instrument (eg, push-pull device).


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Screw insertion

Further proximal and distal screw insertion is completed.

The number and position of the screws inserted is dependent on the individual fracture pattern and bone quality. Ideally the concept of “balanced” fixation should try to be achieved. Usually, the metaphysis requires more screws (3-5) than the diaphysis (2-3). In osteoporotic bone, the number of screws must be increased on both sides of the fracture.

Locking head screws (LHS) may improve fixation in osteoporotic bone and short periarticular segments. Non-locking screws may be used first to reduce the fracture against the plate. They may be sufficient for definitive fixation in the diaphysis.


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Pitfall - Malpositioning of the plate

If the plate is not positioned correctly, there is a danger of missing the bone with proximal screws, or placing them only in one cortex.


Bone grafting

Bone grafting is almost never required, except in open type A fractures with bone loss. In such cases, it should be delayed until the soft-tissue envelope is stable.

7 Plating of the fibula top

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Plating of the fibula

In most A3-type fractures, the fibula is fractured as well and needs to be stabilized. Simple fractures are plated in an open technique as first step of the procedure. Complex fractures of the fibula are better addressed after stabilization of the tibia. An appropriately sized plate, often a 3.5 standard or locking compression plate (LCP) should be used. Lower profile, weaker plates (eg, one-third tubular plates) may be enough for some fractures.

In compromised soft tissues, a minimally invasive plate osteosynthesis (MIPO) can be used also for the fibula. Two short incisions at the level of both plate ends are sufficient to insert the plate from distal to proximal and also to insert 2-3 screws in each main fragment.

8 Final assessment top

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Final assessment

The x-ray imaging at the end of the operation confirms the anatomical restoration of length, alignment and rotation.

For further information see  assessment of reduction.

v1.0 2016-11-22