Open reduction and internal fixation of posterior column tibial plateau fracture with Synthes proximal tibial LISS plate

This is a young patient with a high energy tibial plateau fracture.
The AP X-ray image shows both medial and lateral involvement the tibial plateau.

On the lateral view it can be seen that the fracture is predominantly a posterior shear type injury.
This pattern is difficult to classify using the Schatzker classification system.

This CT scan with 3D reconstruction shows more clearly the large posterior and postero-medial fragments.
This can be considered a posterior column injury and clearly needs to be approached from the back to buttress these fragments and restore the joint alignment.

The anterior imaging shows involvement of the lateral column.
This will also need to be addressed. In this patient a staged approach was used (as for most high energy tibial plateau fractures) with a spanning external fixator applied the day after injury and a delay of approximately 2 weeks to allow the soft tissues to recover prior to definitive internal fixation.

The axial CT images confirm involvement of all 3 columns of the tibial plateau.

Fixation of the posterior column is performed first for which the patient is positioned in the prone position with the whole leg exposed.This allows access for the image intensifier and easy manipulation of the limb to facilitate fracture reduction.

The skin incision involves a horizontal limb along the flexor crease (1.) and a vertical limb along the medial border of the gastrocnemius (2).Dissection proceeds through the fat down the fascia over the posterior compartment.
The fascia is incised in line with the skin incision and full thickness fascia-cutaneous flaps are raised taking care not to undermine the skin edges.

In the mid-line between the gastrocnemius muscle bellies the sural nerve and short saphenous vein, which lie deep to the fascia between the head of gastrocnemius, can be identified and should be protected throughout.

The medial edge of the gastrocnemius (1.) is mobilised exposing the knee capsule proximally and the popliteus muscle over the proximal tibia.

The gastrocnemius is retracted laterally and the popliteus muscle (1.) is elevated to expose the posterior tibia and the fracture (2.).
As dissection proceeds from medial to lateral it should remain beneath the popliteus to avoid damage to the neurovascular bundle, the popliteal artery sits between the gastrocnemius heads on the posterior surface of popliteus along with the tibial nerve. By staying deep to popliteus injury to the popliteal artery and its branches are avoided.
A Hohman retractor can be placed deep to popliteus and gastrocnemius resting on the lateral tibia to improve access, if further exposure is required the medial head of gastrocnemius can be elevated from the femoral condyle with a periosteal elevator. With this approach it is possible to gain exposure of the entire posterior proximal tibia however fixation of posterolateral fragments lateral to the mid-line is difficult, owing to the bulk of the gastrocnemius, and fixation of such fractures may require a specific posterolateral approach or alternative fixation strategy such as rim plating.

To facilitate fracture reduction skeletal traction should be placed across the joint using Denham pins, the femoral pin is placed first, with insertion from medial to lateralAs the patient is in the prone position and distraction of both the medial and lateral sides of the joint is desirable I have opted to achieve this with 5mm Denham pins placed in the distal femur and proximal tibia. The femoral pin has been placed first, with insertion from medial to lateral to avoid risk to the neurovascular bundle on the medial side of the femur. This is inserted with a T-handle under image control, the entry point is on the medial condyle at the midpoint from front to back and insertion should proceed parallel to the joint and the coronal plane.

The second pin is placed in the proximal tibia, this is passed from lateral to medial to avoid injury to the peroneal nerve.Here the entry point is on the lateral border of the tibia sufficiently distal to avoid impeding reduction or fixation of the fracture and again parallel to the joint and the coronal plane.

Denham pins are in position.

On the lateral side external fixator clamps and rods are used to distract the joint using standard Hoffman clamps and bars which can attach directly to the Denham pin.A femoral distractor is then placed on the medial pins to provide further distraction, the distractor arms can be attached directly to the Denham pin and tightened with the butterfly screws (1.)

Once the joint has been distracted room is been created to allow reduction of the articular fragments.

The main posterior fracture fragments can now be seen more clearly, consisting of posterior (1.) and postero-medial (2.) portions.

The posterior fragment is addressed first. The apex is cleared of haematoma and then provisionally reduced with k-wires.It is not possible to see directy into the joint and reduction is gauged by ensuring the apex of the fracture has ‘keyed in’ and radiographically confirmed.

A 3.5mm small fragment T-plate is positioned over the posterior fragment, and its position checked radiographically.The posteromedial fragment remains unreduced at this point as can be seen.
It can seen that it is possible to access the midline of the posterior knee with this approach. The plate is provisionally positioned with K-wires.

The position of the plate is checked on AP and lateral views.

Fracture reduction and fixation takes place with the knee in extension.
Once the plate is positioned satisfactorily, the first screw is placed. The plate is being used in a buttress mode, hence a locking plate is not required, and the first screw should be immediately distal to the apex of the fracture.

The first screw inserted (A) is a cortical screw and should engage both cortices.

As the screw is tightened(A) the plate is seen to buttress the fracture fragment and complete the reduction.At this point no further fixation is performed in this fragment- this allows any necessary adjustments to be made to help with reduction of the remaining fragments.

Once the posterior fragment plate is seated adequately the posteromedial fragment is addressed.Here I have used a Synthes proximal tibia plate. This uses the standard small fragment instrumentation.

The posteromedial plate used here is anatomically contoured with locking screws in the proximal portion.

This plate is well anatomically contoured and the locking screws allow secure fixation of peri-articular bone. It could be argued that in this situation, with the plate acting as a buttress, a locking plate is not required and that a plate that contours to the bone as the screws are tightened will be pre-loaded and provide a more effective buttress.
Once in place the proximal locking screws sit beneath the joint surface.

As before the fracture is provisionally reduced and held with k-wires. A second plate is then used to buttress this in place (1.).The plate is a pre-contoured locking plate but again will be used as a buttress.

The plate is positioned and held with k-wires and the position is checked on AP and lateral imaging.

The first screw is positioned distal to the apex of the fracture in the locking plate, this is a cortical screw which engages two cortices.As it is tightened it will seat the plate, buttressing the fragment and competing the fracture reduction.
In a young healthy patient with normal bone stock I use cortical screws for all of the distal fixation as locking screws offer no advantage.

Once the locking plate is seated with 2-3 further bi-cortical screws distally the proximal segment is fixed.
Here I have used locking screws which will afford better purchase in peri-articular bone, a screw-in drill guide is being used (1.), screw length can be measured directly from the markings on the drill-bit (2.).

The proximal screws of the locking plate are positioned so as not to cross the midline (1.) as this would block the reduction of the lateral fracture later in the operation.
The plate has been used a buttress mode to control the vertical shear force across the fracture and fixation in the proximal segment can be unicortical.

Finally fixation of the posterior locking plate is completed with cortical screws, again these are bi-cortical distally and uni-cortical proximally.

The reduction and fixation is checked on lateral and AP views.
Now that both of the posterior fragments have been reduced the articular surface appears more congruent on lateral imaging.

The lateral column still needs addressing.
The plates buttressing the posterior and posteromedial fragments can be seen in situ however the lateral side of the joint is still widened.

The posterior wound is closed in layers.The popliteus is approximated over the proximal tibia and the gastrocnemius tacked down. The fat layer is closed with interrupted sutures before skin closure with interrupted nylon sutures. A temporary dressing is then applied.

The patent is now turned supine (via transfer onto his bed).The leg is re-prepped and draped leaving the entire leg from mid-thigh distal exposed. A “bump” is used under the knee to facilitate access and allow easier lateral imaging.

An approach to the lateral column is then performed as the final step.
Here I have used a lazy-s incision, this is centred over the joint line and avoids curves gently to maximise exposure without acute angles in the skin edges. This can be centred over Gerdy’s tubercle although I tend to centre this over the anterior fracture window which can be identified with a needle inserted into the fracture line and confirmed with X-ray

For the anterior exposure the fascia is divided longitudinally and then the tibialis anterior (1.) is elevated from the proximal tibia.The fracture is now exposed.

Here I am using a Synthes proximal tibia LISS plate to buttress the anterior split and lateral column.
This comes with an optional jig to facilitate screw insertion and uses the standard large fragment instrumentation.

The jig can be attached to the plate as shown.
I find, however, that the jig tends to rotate the plate off the bone and my preference is to insert and attach the plate freehand.

A screw-in drill guide (1.) is inserted into the proximal end of the LISS plate to help with plate insertion.

The proximal tibial LISS plate is inserted by sliding it beneath the tibialis anterior, where it is held with a large pointed reduction clamp.
Often it helps to make a track with a periosteal elevator prior to insertion. Proximally the plate is held with a periarticular clamp (1.), distally a small incision has been made over the distal end of the plate (identified with image intensifier) and then the plate provisionally held with a k-wire (2.).

The plate position is confirmed on imaging proximally.
The joint reduction (1.) is checked again and the plate is confirmed as sitting centrally on the proximal tibia (2.).

Radiographic confirmation that the plate is sitting on the tibia distally.
Often it sits off the bone, particularly with longer plates.
If this occurs an incision is made over the intended plate position distally and the plate manipulated to the desired position, the incision used to insert screws later on.

The LISS plate position in confirmed on AP imaging as well as lateral, proximally and distally.
It should be seen to sit against the tibia- the LISS proximal tibia plate generally has a good anatomical match and should sit well.

The LISS plate is also being used in a buttress mode to fix the lateral column.The first screw is inserted in the hole immediately distal to the fracture apex. This is a 4.5mm (3.2mm drill bit) cortical screw which should engage both cortices.

As the first LISS plate proximal screw is tightened the plate sits onto the bone and fracture reduction is completed.

Further fixation of the proximal segment with the LISS plate is completed, using locking screws if required(1.).These 5mm screws and are inserted after drilling with a 4.3mm drill bit and measuring with use of the screw-in drill guide and direct measurement from the drill-bit. The screws pass all the way across the proximal tibia but care should be taken that they are not prominent on the medial side. Three or four screws are placed in the proximal segment.

Distally screws are inserted percutaneously, using locking or cortical screws into the LISS plate.In young patients with normal bone there is no need to use locking screws in the tibial shaft so I have used 4.5mm cortical screws engaging both cortices. A total of 3 or 4 screws are used.

Final check images are taken in theatre to confirm reduction and no hardware prominence.The joint surface is checked again (1.) as well as screw lengths and position (2.).

On the AP view the joint surface is checked and overall alignment.
Following check imaging the wound is closed in a layered fashion.
The fascia can be closed over the plate then subcutaneous fat with interrupted vicryl sutures and finally interrupted nylon to skin. Dressings are applied, my preference is for non-adherent dressings (minimise skin shear with swelling) such as gelonet and then a wool and crepe bandage.

Post-Operative AP image

Post-Operative lateral image.