Ankle fracture- Arthrex tightrope for acute syndesmotic injury and Stryker Variax plate for fibula fracture

Very clear radiographic asymmetry of the ankle mortise in a chronic case with syndesmotic disruption.
There has been some reasonable degree of deltoid injury as evidenced by the calcification in the region of the deltoid (1) and malunion evident (2) of a fairly distally placed Weber B ankle fracture.

The initial imaging associated with a syndesmotic injury is almost invariably a plain X-ray of the ankle, ideally a mortice view (15 degrees of internal rotation).
If this is equivocal a CT is most often deferred to.
In predominantly ligamentous injuries, an MRI gives a more direct assessment of the extent of ligament injury, but the symmetry of the joint can be more difficult to assess.
This is a different case of a professional rugby player with a several week old “sprain`’ that is not settling. There is clear evidence of a significant deltoid ligament injury (1) and more subtle evidence of mortice asymmetry (2),with a slightly wider medial joint space.

This slice from the same patient shows more convincingly the widening of the medial joint space (1) and the lateral drift of the talus (2), permitted by the increased mobility of the fibula also.
A CT would be even more definitive in terms of the joint asymmetry, without the soft tissue signals to distract.

This is the same patient again. The sagittal T1 imaging shows that the injury is not wholly ligamentous, with a posterior malleolar fracture indicating a more significant and circumferential injury has occurred to the ankles soft tissues.

The on-table AP view during surgery for the rugby player at first viewing does not obviously show a widened medial gutter.
This is however a projectional effect, due to the width/depth of the medial malleolus being imaged producing a “double shadow” medially. When an internal rotational image is taken the extent of the injury is obvious.

The same ankle with the AP view taken in 15 degrees or so of internal rotation. The lateral talar shift and asymmetry are both easily visible.
This is without the need to apply an external rotation and abduction force across the ankle.

This is a separate patient, also a sports person, with a Weber B Fibula fracture and associated syndesmotic injury.
An ankle arthroscopy has already been performed and the leg is positioned on a sterile bolster and with a sandbag under the ipsilateral buttock, to allow positioning of the foot in neutral rotation.

The dimensions of the fibula are palpated, in particular its tip and the position of the mid-shaft, in planning the location of the incision.

The skin incision runs along the mid-axis of the fibula, extending 3cm or so above the estimated point of the fracture, and curving gently anteriorly 20 degrees or so once the fibula tip is reached.

Once skin and the first few mm of fat are incised further progress is with a fine tenotomy scissors to dissect deeply.Anteriorly in the fat layer is the superficial peroneal nerve that ideally should be identified and avoided. The objective though is deeper progress down onto the fibula, so if the nerve is not easily seen it is probably out of harms way, as its’ course is quite variable.
Posteriorly sits the sural nerve, but this is quite a way posterior and runs in proximity to the peroneal tendons. It need not be sought specifically but be aware of its presence especially when positioning sharp-toothed self retaining retractors.

Small veins usually traverse the fibula at this level and unless varicose (when they should be tied off) can be diathermised with bipolar diathermy.

Haematoma is usually visible once close to the fracture site and subperiosteal dissection with a knife is used once through the deeper fat layers.

Sharp, subperiosteal dissection is used posterior to the Fibula to elevate the peroneal tendons and their sheath from the bone to expose the proximal extent of the fracture

Sharp dissection into the fracture helps define what is bone and what is fibrous tissue.
This injury is several weeks old and there is little remaining actual haematoma. There is fibrous tissue masking the fracture plane though that needs to be excised.

The fracture position (referencing from the distal fragment) can be seen to be slightly shortened, externally rotated and retroverted.
An understanding of the mechanics of the injury and the resulting fracture position is helpful in guiding the direction of the forces that will be required to reverse this position and reduce the fracture.
The step prior to this though is dis-impaction (see step 18 onwards)

A sterile ruler is used to estimate the size of fibula plate that is going to be needed.
It is important that the most proximal extent of the fracture is identified, this is usually situated on the posterior aspect of the fibula. The fixation needs to be 3 screws (or 6 good cortices) above the most proximal extent of the fibula fracture.
With the Stryker Variax plating system, the options are either for a straight fibula plate, a one third tubular plate or a distal lateral fibula plate (this version has a broader distal extent to catch more of the distal fibula). The plates range from 2 holes to 16 holes length, though not each plate is available in each length.

The fracture, once it has been sharp dissected to free it, is first distracted and displaced further to dis-impact it, mobilise it and aid reduction.Here a Lambottes’ osteotome is being used to achieve this.
Hanging the ankle off a sterile bolster means that gravity assists with distraction of the fracture as well.

Further dis-impaction of the entire fracture is occurring again using the Lambottes’ osteotome(1). Adequately mobilising the distal fragment is required to aid anatomical reduction.
Gravity is also used to help this process, by the positioning of the ankle dependent off the posteriorly placed sterile bolster as seen here.

The fracture is lavaged and any remaining debris removed from the fracture interface, prior to attempting a reduction

To get the fracture reduced, the distal fragment will need to be first distracted and then internally rotated back into its previous position.The most posterior and superior point of the fracture is useful to gauge whether this has been achieved by seeing how well it fits back into its previous position. The anterior aspect of the fracture also is useful in gauging this.
Reduction may simply be possible by indirectly placing traction upon the distal fragment by pulling the foot. More often it requires the use of a reduction clamp on the distal fragment, though care should be taken as the bone of the distal fibula is often not very tough and can fragment.
Once the fracture has been placed into an approximate position, further and better apposition of the bone ends can be achieved by the application of a pointed bone reduction clamp, as is shown here. This is used to compress across the fracture.
It is worth being critical of yourself with this stage of the operation and if reduction is not near anatomical (in a fracture that allows this level of certainty) then the reduction clamp should be removed and the fracture should be once again manoeuvred in a similar fashion.
When applying the reduction clamp it is also worth bearing in mind the position that a lag screw will be drilled shortly from the anterior/superior aspect of the fibula. Ensure that the reduction clamp position does not get in the way of this.
The reduction clamp also should be positioned such that it is possible to easily manoeuvre a plate beneath it whilst keeping the reduction clamp in situ.

Once the fracture has been placed into an approximate position, further and better apposition of the bone ends can be achieved by the application of a pointed bone reduction clampThe reduction clamp has been simply been angled more proximally in this slide and the reduction can be seen here to be not quite anatomical.

A second clamp has been applied to the fracture and this is a crocodile jawed version that exerts less “point-pressure” that the pointed reduction clamp.
Again this should be positioned so as not to impede the position of the lag screw or the distal fibula plate.

Here the subcutaneous fat is closed with an interrupted 2.0 Vicryl suture.

The previously chosen fibula plate is slid along the fibula and is offered up to the bone.Here it is sitting off the most distal part of the fibula and it is usual to need to do some contouring to get a better fit.
The implant used here is a Stryker Titanium Variax plate.

This is one half of the plate bending apparatus for the Stryker Variax set.
The distal end of the plate is placed into the slot marked 1.

There are specific forceps which are used to contour the plate. These need to be accurately placed into the locking holes and firmly closed so the thread mechanism of the locking thread is not damaged by this step.

The plate is now re-applied to the fibula and can be seen distally to be sitting well opposed to the bone.
At this stage one should be planning for the various fixations that will be needed, and positioning the plate holes appropriately.
In particular one is looking to ensure as many points of fixation into the distal fragment as possible, which is the rate limiting step.
The plate can be slid superiorly or inferiorly to get an extra hole here or there. The fracture itself will need to be avoided and the potential for syndesmosis fixation should also be borne in mind and holes in the plate specifically left for this.

The distal of the two clamps has been placed in a position that it will interfere with the first fixation, the lag screw and this needs therefore to be moved.

The crocodile clamp has been removed and a fine pointed clamp has been used instead and this is rotated distally to give adequate room for the lag screw fixation (1).

The proximal, gliding, hole for the lag screw will be drilled first using the colour coded red guide and drill on the Stryker set, that produces a gliding hole.

The guide is placed on the cortical bone and the objective is to place the lag screw at approximately 90 degree angle to the fracture line.
One should be careful not to place the entry point too close to the fracture, as when the screw is finally driven home, there will be a tendency for this to fracture into the primary fracture line.
One should also be mindful of the fracture geometry posteriorly so that the drill exits (though this will not be the drill to exit posteriorly, it will be the subsequent 2.6mm drill) through good bone.
What is evident on this slide are the peroneal tendons (1) and these also need to be avoided in the next step of the drilling.

The yellow colour coded drill guide in placed into the gliding hole. This will guide the smaller 2.6 mm drill into the distal fragment.There is some “play” possible at this part of orientating the guide and again the objective is to achieve good purchase in the posterior aspect of the distal fragment, so good quality bone away from the fracture site is required.

The colour coded yellow drill is used to drill the distal/posterior hole. Care should be taken not to overshoot posteriorly, which risks damaging the peroneal tendons.

Once the bone has been fully drilled for the lag screw a depth gauge is offered up. It should be possible to see posteriorly the exit point of this. This is measuring 28mm and some length should be removed from the measured length to ensure the tip of the screw is not impinging on the peroneal tendons.

A partially threaded cancellous screw is used for the lag screw and as it is driven home, the fracture is carefully observed to ensure compression is achieved.
It is also not a bad idea to gradually tighten the screw, stopping every few turns. It is easy to propagate a fracture from the drilled superior gliding hole into the main fracture, by over-vigorous tightening, which should be avoided.

With the screw fully driven home, there is evident compression across the fracture site.

The plate is now offered up to the fibula again. The forceps here are seen pointing to a hole that will not be used and which directly sits over the fracture site. This still leaves 3 holes available for fixation in the distal fibula.
The smaller holes evident on the plate are for guide wire fixation if a surgeon desires to hold the plate temporarily.

The contoured fibula plate is fixed following lag screw fixation.The yellow guide for locking screws is used for the distal end of the plate. This guide accepts a 2.6mm drill which is also colour coded and the guide is marked 2.6mm.
The guide needs to be seated accurately in these threaded holes, inaccurate placement of the drill risks the subsequent threaded screw heads not aligning with the threads on the plate.
Even with this locking mechanism there are still 15 degrees of angulation that can be achieved with the guide, either side of a neutral line.
Care must also be taken when drilling distally not to over penetrate the fibula causing damage to the lateral aspect of the ankle joint.
Drilling can be done under image intensification or simply carefully by feeling for when loss of resistance occurs and not then over penetrating further.
The hole, once drilled, needs to be measured with the standard guide and an appropriately sized locking screw is taken and then inserted.

A 3.5mm locking screws are inserted into the drilled and measured distal holes.
Drilling of the most distal hole will need to be angulated slightly proximally to get as much bone purchase as possible here.
Locking screws in the distal fibula, where the bone quality can be poor, is definitely a helpful part of the Stryker plating system.

Further fixation under the same conditions is performed for the remaining holes.

Further fixation under the same conditions is performed for the remaining holes.

The proximal fibula holes are drilled following distal fixation, the screws being inserted at right angles to the long axis of the fibula.Note that there are 3 holes which have been left unfilled. The most distal sits at the fracture line but the first two holes in the proximal fragment have been left for potential syndesmotic fixation, given the pre-operative appearance of a widened ankle mortise.
This fixation with a tightrope can also sit outside the plate, space permitting.
At this point, once the fibula fixation is completed, the syndesmosis should be screened with the II whilst distraction is applied across the tibio-fibular interface by inserting a small periosteal stripper or similar.
A number of cases with a widened mortise at this point will have been stablished and the mortise reduced.

1-Fracture line
2-Hole left in plate for tightrope implant
3-Hole left in plate for tightrope implant
4-Peroneal tendons

The Arthrex tightrope kit comes with several straightforward components.
Guidewire for cannulated drill bit (1)
Cannulated drill bit (2)
Non-cannulated drill bit (3)
Arthrex tightrope (not yet opened, 4)
Disposable guide for drill (5)
My own preference is not to use the guidewire and cannulated drill and this is based on my own experiences of the guidewire being slightly narrow gauge and the distal end of the cannulated drill being sharp, which risks shearing of the guide-wire.
There is no issue simply using the drill under image intensification and with clear reference to the anatomical landmarks.

The ankle mortise needs to be reduced and reduction held and an excellent tool for this is the large pointed AO reduction clamp.
This needs to span between the distal fibula and the medial malleolus and this instrument is fit for this purpose in all but the most swollen ankles.

The large AO reduction clamp is applied by inserting into one of the screw heads on the lateral aspect of the ankle and medially into good bone of the subcutaneous border of the tibia.
Medially it is important that the saphenous nerve and its associated vein is palpated for and avoided if possible, though its course is slightly variable.
On this image, the tip of the tenotomy scissors are being pointed into the syndesmotic area which can be visualised whilst compression is applied across the ankle mortise to produce reduction of the widened joint. It is important that compression is applied with the ankle placed into neutral position so that the talar dome is at its widest point.

A mainly ligamentous example of a syndesmotic injury in a professional rugby player, whose MRI was shown at the start of the technique, with a small associated posterior malleolar fracture.

An effective reduction now achieved with the reduction clamp, the ankle having been placed into neutral dorsiflexion during its application.

The image here shows the ankle being held in neutral with the large AO pointed reduction clamps in position.
The mortise is screened under image intensification.

The 3.7mm drill bit is inserted into one of the holes that has been left free in the distal fibula plate for the first of the tightrope implants, avoiding the fracture site.
The surgeon’s hand should be dropped and the approximate angle aimed relative to the coronal plane is 30 degrees.
The drill should be exiting through the subcutaneous border of the tibia and it should be borne in mind that the fibula sits relatively posterior to the tibia. Before drilling commences check visually the trajectory that the drill will follow and ensure it will exit through the subcutaneous border, and not posteriorly.
It is key to remember that an immediate relation to the postero-medial border of the tibia is the posterior tibial neurovascular bundle.
Unlike bone, it does not yearn to be drilled through.

The drill for the tightrope should be parallel to the articular surface of the tibial plafond and should sit approximately 1.5cm above the tibial plafond, the approximate angle aimed relative to the coronal plane is 30 degrees.The orientation of the drill is screened before drilling commences, as well as during drilling (in the AP plane) by the image intensifier.
The ankle is being pushed into neutral, and the surgeons hand will be dropped, before drilling starts.

The angle in this case of the drill from the coronal plane appears closer to 20 degrees, though the leg is slightly internally rotated.
Its trajectory should exit well through the subcutaneous border of the tibia, rather than in any way posteriorly.

The image intensifier picture showing the drill parallel to the articular surface and sitting at an appropriate distance above the joint line.

The drill needs to break the medial tibial cortex.

The Arthrex tightrope is taken from its package. The rectangular button that sits on the medial malleolar bone (1) is attached to the end with the sharp introducing needle (2). The end that sits on the fibula, or fibula plate, (3) is circular in shape.One needs to be careful not to advance the circular button towards the rectangular button at this stage and this is done by avoiding placing traction on the lateral suture tails (4).

The difference in the shape of the medial malleolar(1)and fibular buttons(2) is well shown here.
Note also that 4 strands of fibrewire run between these two anchor points.

The tightrope introducing needle (1) is been routed through the screw hole and out through the medial malleolar skin.This has attached to it a smaller gauge suture which pulls with it the medial/rectangular button.
Any debris/swarf should have been cleared from the drilled hole in the fibula prior to its introduction, or this risks snagging the button and suture.

Tension is taken up on the introducing suture now through the medial tibia and the oblong suture button is introduced into the lateral fibula hole and pulled across through the bone tunnel, using steady traction.Its passage should be easy.
The button should be easy palpable once it broaches the medial malleolus and at this point should be manipulated by hand in the subcutaneous fat layer and flipped back upon itself, coming to lie at right angles to its previous trajectory so that it sits flush on the medial malleolar bone.
What will also assist this is some gentle retrograde traction on the fibre wire suture.
The position of this button should be checked with the image intensification.
There is soft tissue medially that can prevent it from “snugging down” onto the medial malleolar bone and on rare occurrences, if it is resistant to sit flush, a small incision may be required to introduce a mosquito, or similar forceps, to put direct pressure on it so it does sit flush on the medial malleolar bone. Care must be taken not to cut the Fibrewire if this is done. Consider offsetting the small cut and not placing it directly over the button.

Lateral traction is exerted upon the lateral tightrope suture (1) to pull the medial button onto the subcutaneous border of the tibia.

Here the rectangular button(1) can be seen before it has been flipped back to sit on the medial malleolus.

Once the medial button is in place, the circular button is delivered into position by traction on the two free ends of the fibre wire suture(1).It is important that whilst the button achieves its final position, the ankle is placed into neutral dorsiflexion, which has not yet happened in this slide.

The fibula button is now in position and further tension is applied to the suture ends.

The fibre wire is tied and relatively long suture ends are deliberately left.

The image intensifier picture confirms the anatomical reduction of the ankle mortise, as well as good position of both suture buttons(1,2).

The second tightrope bone tunnel should be parallel to the first and again this is performed under image intensification.A second tightrope anchor needs to be placed.

Again, the two different button ends of the tightrope are well shown here.

The rectangular medial malleolar button has already been placed in this slide.

On this occasion it has been necessary to make a small nick in the skin to manoeuvre the medial malleolar button and it can be seen here that the button has in fact transgressed through the skin surface(1).

The second buttons position has been flipped through 90 degrees and it is at the moment sitting slightly off the subcutaneous border of the tibia. Retrograde traction on it will allow it to seat better on the bone.

Here both suture buttons are sitting appropriately placed following tying off of the tightrope.

The lateral appearance of the fibula fixation and tightrope fixation.

Both tightrope sutures have been left relatively long and these have been well placed beneath the soft tissue envelope and not prominent.
The wound is washed through with aqueous betadine before closure.

A single deep vacuum drain is placed close to the plate.
It is important to avoid catching the superficial peroneal nerve anteriorly or sural nerve posteriorly when placing this suture.

The fat layer has been deeply closed and a further more superficial fat suture will be used prior to subcuticular closure.

Back to the rugby player again, with a small posterior malleolar fracture and otherwise a soft tissue medial and lateral injury.
3 tightropes were used, well spaced across the interosseous membrane to maintain reduction of the syndesmosis.
The neutral rotation post-operative view gives no indication of the position obtained.

The 10 degrees internal rotation view also does not represent the actual position obtained on table, though on occasion will.

It is in this case the 20 degrees internal rotation image that confirms things are as they should be.