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Pilon Fracture- C-type fixed with Stryker AxSOS 3 Periarticular Plating System

    Overview

    Learn the Pilon Fracture: C-type fixed with Stryker AxSOS 3 Periarticular Plating System surgical technique with step by step instructions on OrthOracle. Our e-learning platform contains high resolution images and a certified CME of the Pilon Fracture: C-type fixed with Stryker AxSOS 3 Periarticular Plating System surgical procedure.
    Pilon fractures are defined as intra-articular fractures of the distal tibial plafond and being in a load bearing joint they are serious and usually life changing fractures. The fracture is produced by a mixture of shear and compressive loads to the distal tibial metaphysis. Often such fractures are associated with other severe injuries to the ipsilateral limb, pelvis or lumbar spine.
    Pilon fractures make up between 5 and 10% of all lower limb fractures and because of the energy involved are associated with a high (15 – 55%) complication rate.
    Significant rotational force alone can also cause distal tibial fractures involving the plafond and these are also Pilon fractures. This mechanism though usually results in less severe soft tissue damage and less compromise to the articular surface in terms of comminution and cartilage damage.
    The most frequent mechanism of injury is a fall from height though road traffic accidents also account for a good proportion of high energy Pilon fractures. This patient also sustained an ispilateral open femoral fracture which was plated on day one of the injury when a temporising external fixator was applied in a delta construct to the ankle.
    In terms of operative management, the big debate is when to use ORIF or minimally invasive plate osteosynthesis (MIPO), and when to use an external fixation frame (such as an Ilizarov or other fine wire construct) as definitive treatment. It is with this in mind that there is currently a multi-centre randomised control trial comparing these two forms of treatment, funded by the NIHR (National Institute for Health Research) in the UK. This study is called the ACTIVE Trial (Articular Type C Pilon Trial Internal Vs External Fixation) being run by the York Trials unit. This patient was recruited into this trial and randomised to Internal Fixation.
    In my hands and working in a unit with excellent fine wire fixation skills we treat those cases where there is very severe soft tissue damage, or where the articular surface is grossly comminuted, with a frame. Those cases where the degree of articular comminution is less severe are usually treated with plate fixation as with the case presented here.
    Readers will also find of interest Chris Blundells other OrthOracle instructional technique for surgical treatment of a Pilon fracture Internal fixation of distal tibial Pilon fracture using Stryker AxSOS 3Ti plate. and also Paul Fentons technique Open reduction and internal fixation of C-type Pilon fracture using Smith and Nephew EVOS small fragment system.

    Indications

    INDICATIONS
    Pilon fractures most often occur in high energy injuries as in this case (a motorcycle accident) and the most common of these is a fall from height. The injuries are often accompanied by associated fractures of the pelvis (vertical shear), lumbar spine (burst fractures) and the ipsilateral foot (calcaneal fractures being the most common). Pilon fractures make up between 5 and 10% of all lower limb fractures and because of the energy involved are associated with a high (15 – 55%) complication rate. Significant rotational force can also cause distal tibial fractures which involve the plafond and these are also pilon fractures, such as in skiing. This mechanism though usually has less severe soft tissue damage and less compromise to the articular surface in terms of comminution and cartilage damage.
    The outcomes of these fractures are related to the degree of violence which has been inflicted on the articular surface and also to accuracy of the restoration of articular congruity.
    Throughout the treatment of these injuries focus should remain on the soft tissues as it is these, which if compromised, will lead to a disastrous outcome. With this in mind care must be taken to time the surgical intervention appropriately. It is often best to allow the soft tissue trauma to settle down by stabilising the limb with the use of a bridging mono-lateral external fixator and avoiding further immediate insult to the soft tissues by the use of early extensile open approaches. This was demonstrated by Sirkin et al in 2004 (see below) and was the approach used in this case.
    SYMPTOMS & EXAMINATION
    Full ATLS guidelines must be followed in patients with these injuries as life threatening associated injuries are not uncommon. The limb must be inspected fully for breaches to the skin either from within (ie an open fracture) or from outside in which may or may not communicate with the fracture but which non-the-less may compromise operative treatment. The limb must be assessed for neurovascular compromise. Immediate splintage in the form of a full length backslab cast is mandatory to provide comfort and to assist in soft tissue management.
    IMAGING
    Plain AP and Lateral radiographs are needed and should also include the whole leg to the knee.
    CT scanning is extremely helpful to plan intervention. I would not intervene in my hospital without one as my approach to the fracture is determined by the fracture configuration with particular reference to the transverse sections.
    ALTERNATIVE OPERATIVE TREATMENT
    The big debate is when to use ORIF or minimally invasive plate osteosynthesis (MIPO), and when to use an external fixation frame (such as an Ilizarov or other fine wire construct) as definitive treatment. The literature does not help greatly here though the Watson et al paper (see Results) is one of the more compelling papers towards fine wire fixation whilst more recently the techniques and outcomes described by Xianfeng’s group (see Results) leads one to have confidence in ORIF.
    In my hands and working in a unit with excellent fine wire fixation skills locally we tend to treat those cases where there is very severe soft tissue damage or where the articular surface is grossly comminuted with a frame. Those cases where the degree of articular comminution is less severe are usually treated with plate fixation as was the case presented here.
    We not infrequently combine approaches also. For example, where there are a few fragments which can be reduced and stabilised with screws or a die punch fragment which can be reduced with minimally invasive assistance but the whole limb secured then with a circular frame.
    NON-OPERATIVE MANAGEMENT
    If the soft tissues are severely compromised such as in a pre-existing neuropathic limb or a vasculopath, the risks of a non healing wound may well outweigh the benefits of articular restoration. In such cases the limb is best treated with a cast but with frequent inspection of the soft tissues to ensure the situation is not worsening.
    CONTRAINDICATIONS
    In a situation where the limb is unsalvageable usually due to vascular or neurological compromise or where there is significant soft tissue loss; then a well timed and carefully considered amputation can lead to an early return to function and an acceptable outcome especially in the strong and fit young patient.
    Sirkin M, Sanders R, DiPasquale T, Herscovici D Jr. A staged protocol for soft tissue management in the treatment of comples pilon fractures. J Orthop Trauma. 2004;18:S32–S38

    Setup

    The patient has a general anaesthetic if able. Blocks in my opinion are best avoided due to the small but very real possibility of masking a compartment syndrome post operatively.
    The patient is supine with sandbag under the ipsilateral buttock to position the limb in neutral rotation. A tourniquet at the thigh is usually applied and I prefer to operate with this inflated so that I can have a clear view of the surgical field. However in this case the patient has sustained an ipsilateral open femoral fracture and so a tourniquet could not be used.
    I prep the limb to well above the knee as rotation needs to be carefully assessed. Unless the injury is an open one with bone loss then iliac crest bone grafted is not needed.
    Antibiotics on induction of anaesthesia are mandatory and in our hospital currently this is in the form of teicoplanin and gentamycin delivered iv.
    An image intensifier will be required later on and I ensure the equipment is in the operating room before I begin. The plain radiographs and CT scans are displayed on the screens to help reference the approach and remind us of the pre-operative plan and specifically which fragments to attach to which.

    Operation – 1

    The initial plain AP Xray looks quite acceptable, but is clearly a C-type injury, and requires a CT for adequate radiographic assessment.
    For a comprehensive review of the common classifications used in planning (and an example of another Pilon injury) readers should consult Paul Fentons technique and in particular the indications section Open reduction and internal fixation of C-type Pilon fracture using Smith and Nephew EVOS small fragment system.

    The sagittal CT gives a better perspective of the magnitude of the surgical task about to be undertaken.

    The external fixator has allowed the soft tissues to settle
    This Delta frame construct is essence two triangles. It has a triangle configuration in the frontal plane to provide stability to abduction and adduction forces, and uses three pins in the the tibial proximal to the fracture and two pins distally. The calcaneal pin in fact is a Denham pin that traverses the calcaneus and provides excellent strength in the heel.

    The Delta frame is also stable in the frontal and also the sagittal plane due to the triangular construct used. I often add a bar between the 1st metatarsal pin and the calcaneal pin on the medial side to add stability within the foot. The soft tissues are not very swollen now at 1 week post injury.

    A longitudinal, anterolateral approach to the fracture is used, centred over the area of maximal fracture comminution.The External fixator is partially dismantled to allow access but the medial construct remains intact to add stability during the case.
    The surgical approach is a direct one onto the maximal point of comminution, which in this case is antero-lateral. This is as described by Toplis et al from Bristol, UK in their paper from 2005 .
    This will allow the point where the soft tissues, although injured, may be dissected and used to gain access to the fracture, without a second injury or further soft tissue dissection.
    The anterolateral incision is positioned such that the superficial peroneal nerve is not in the wound. The nerve can be seen usually by plantarflexing the fourth toe and the skin is seen to tent up over the nerve
    Topliss CJ, Jackson M and Atkins RM.Anatomy of pilon fractures of the distal tibia. J Bone Joint Surg (Br). 2005 May;87(5):692-7.

    In planning the location of the anterolateral incision the skin bridge between it and the planned lateral incision to the fibula must be at least 5cms in width.This is to minimise the risk of the bridging skin necrosing.

    Careful skin dissection is needed due to the delicate injured skin. Skin edges are retracted with hooks or fine forceps. The bruised soft tissues can be clearly seen in the proximal part of the wound (A). Care is taken to look out for the superficial peroneal nerve.

    After the anterolateral skin is incised dissection is deepened through the subcutaneous fat, avoiding undermining the skin.The superficial nerve is reflected medially in this case as dissection proceeds with care through the subcutaneous fat

    Extensor digitorum longus tendons(1) are reflected laterally, tibialis anterior muscle (2) is reflected medially and the interval between them explored and deepened. The EDL tendons and if present (it was not in this case) the tendon and muscle belly of peroneus tertius are reflected laterally. The inferior extensor retinaculum(3) is carefully divided and made available for later repair.

    Deep to the fat the anterior capsule is seen to bulge with haemarthrosis if intact, or if already torn then the joint will be visible deep and the capsule can be reflected to explore the distal tibia fracture. In this case it was intact and so was divided longitudinally.

    Once the ankle joint is opened by a longitudinal capsulotomy the order of fixation is initially to reduce and stabilise the articular surface of the distal tibia and then to link this stable distal part to the metaphyseal element of the tibia.Articular restoration however is key and we start with this.
    The anterolateral fragment is immediately visible.
    The unstable periarticular fragments have tentative soft tissue attachments which must be preserved. Use dental hooks (H) to move these and manipulate them without causing any “second hit” to the poor blood supply locally. The fragments can be hinged open like a book and the deep articular surface inspected and any dye punch fragments reduced before closing the book and fixing.

    The unstable periarticular fragments have tentative soft tissue attachments which must be preserved. Use dental hooks to move these and “hinge” them open to inspect and reduce the deep aspect of the articular surface.Self retaining retractors should be avoided as these will cause further trauma to the fragile and injured skin edges and potential subsequent poor wound healing.
    The apex of the fracture fragment and the defect where it has come from in the tibia are good landmarks to gauge reduction of the fragments

    In order to achieve as close to anatomic reduction as possible at the level of the joint any early callus and haematoma which has formed at this stage needs to be removed – a fine suction tube does this well. Lavage is also used to clear this and gain a good view.
    The damaged surface of the talus can be seen here too (T).

    Lavage with a syringe and small needle is used.
    I find a syringe delivers fluid under pressure and accuracy and helps to gain a good view, which is of course vital to get the joint restored accurately

    Once identified, individual fragments are reduced and held temporarily with k-wires put in under power, with an appreciation of where the plates will eventually sit. I tend to use 1.6mm wires as these are robust enough without fracturing the small pieces.

    Joint congruence is checked with image intensification after the articular fragments have been stabilised with K wires.The objective so far is to restore the joint surface prior to stabilising the joint to the shaft with plates.
    An image intensifier is needed to make sure that the joint is restored and that the talus is anatomically reduced in both lateral and AP images. The more proximal fractures are yet to be stabilised and can clearly be seen to be displaced still at this stage.

    Once the joint is restored the plate is applied. The first step is to make a pocket deep to the muscles, for the plate to be passed up the tibia.The Stryker set includes an excellent long soft tissue elevator which is used to make a pocket deep to the muscles, for the plate to be passed up the tibia.
    Care must be exercised to make sure the plate is well aligned to the shaft as one doesn’t want to keep passing the stripper up several times with the risk of harming the periosteal blood supply to the tibia.

    An appropriate length plate is selected for the anterolateral fixation, and needs to be long enough to have at least 3 holes proximal to the most proximal extent of the fracture of the shaft in order to give adequate stability, even with a locking plate.The plates are sterile packed and so the choice of length is based on measuring the length of tibia to be bridged. In this case a 10 hole plate is chosen.
    It is introduced using the specific distal aiming block which can be seen in detail on slide 35 for the medial plate. The introducing handle (H) clips onto this guide.

    The plate slides easily submuscularly, into the pocket made earlier without disrupting the tibial metaphysis.

    Once introduced the plate seats well on the distal anterior surface of the tibia without the wires interfering. An additional wire is passed though the wire hole in the plate to add security and to check subsequently that it is distal enough without screws being introduced intra-articularly.

    Image intensifier is used again to make sure all is correct at the joint line before fixation of the anterolateral plate commences.The plate is seen to sit satisfactorily and that the double distal rows of screws will capture the articular fragments well.

    A metal instrument is used to check the proximal extent of the anterolateral plateNow we need to ensure the plate length is correct and to plan our next proximal incision to stabilise the proximal plate to the diaphysis of the tibia

    At the proximal limit of the plate the metal marker is used to show where the incision should be made and also that the plate is ‘standing’ off the tibial shaft. It creates a more stable construct if it is applied close to the bone and is also less likely to irritate the soft tissues.

    A small incision is made proximally to fix the plate to the shaft and to allow three screws to be introduced.The initial device inserted proximally is a plate fixation device(1) to bring the plate closer to the bone

    The anterolateral plate is reduced onto the bone using the AxSOS bicortical plate fixator pin as the first form of fixation.The AxSOS system uses a bicortical plate fixator pin(1) which is introduced through a guide and with the sleeve placed over this and wound down until the plate is on the bone.
    This pin should be introduced by hand to avoid overheating the bone if it is drilled in. It will be replaced with a locking screw later – slide 28. In this case this aids medial translation of the separated metaphyseal fracture also. Note the medial external fixator construct remains in situ.

    Operation – 2

    The distal part of the anterolateral plate is fixed to the tibia with screws positioned using sleeves through the aiming block.The distal articular part is now stabilised with screws positioned using sleeves through the aiming block. A mixture of locking partially threaded or fully threaded is used depending on the exact orientation of the screws and fragments with compression achieved by lagging where possible. The distal row of holes do not accept locking screws but non locking in 2.7mm and 3.5mm diameter are available

    The distal lag screws should be applied before the locking screws so that compression at the level of the articulation is achieved.This is the “lag before lock” principle in practice. Here the sagittal plane is well reduced and compressed.

    After the distal fixation has occurred for the anterolateral plate, proximally the drill sleeves are inserted and locking screws positioned after drilling with the 3.1mm drill.These screws are best inserted by hand rather than power to avoid thermal damage and cold welding. The torque screwdriver should be used to finish off the screw into the plate and applies 2.5Nm of torque. The temporary plate fixation pin can now also be replaced by a locking screw in the 2.5mm hole where the pin was.

    An image intensifier is used to check the proximal locking screws are correct length.

    Direct vision shows the joint is well reduced and the external fixator can be removed at this stage as we now have some stability of the tibial shaft. However the fibula needs fixation to aid stability and gain anatomical ankle joint congruity.

    The wires that are introduced are put in with an eye on where the subsequent plate may sit as it is frustrating and risky to keep moving these wires as the operation proceeds and if the wires are in the way of the plate.

    The wires can be seen to be at tangents in the transverse plane.
    The wires are put in tangentially to add stability.

    A direct approach is made over the fibula fracture, following which the fibula is bridge plated.The approach is standard for a fibula fracture. Skin and fascia are incised and the fibula fracture located. The violence which had been applied to the limb has caused much fibula comminution and periosteal stripping.
    The limb is rotated internally by my assistants, or more sandbag supports, and I sit low down to see this stage well.
    Remember that this approach is quite posterior, to maximise the skin bridge to the anterolateral approach

    The fibula is plated in a bridging manner using a straight fibula locking plate. The fibula plate is clamped to the fracture to get good alignment of the fibula. Locking screw fixation is used to gain stability.

    A 3cm incision is made centred over the medial malleolus. Dissection is to the periosteal deltoid sleeve.An EUA of the construct reveals that the shaft remains unstable particularly the medial side where there is an unstable segment. With this in mind I plan a MIPO plate to the medial side of the tibia.

    Medial distal tibial locking plate is selected and the aiming guide is attached to the plateAgain the plate is selected after measuring the length needed with image intensifier as for the antero-lateral plate.
    The distal aiming block can be seen here. This is locked to the plate, bearing in mind that the hole where these lock together is not suitable for a screw.

    The aiming guide provides a stable attachment for the introducing handle but also for the subsequent drill sleeves so that all locking screws are well orientated. It should be noted that the measurer does not account for the drill sleeves in the aiming guide.
    Power for screw introduction should again be avoided to stop cold welding.

    The soft tissue elevator again is used to prepare a plate pathway in the submuscular plane medially.Care is taken to ensure this is directly up the tibia and not angled either posteriorly or anteriorly. The elevator is gently inserted with respect for the fracture site and the periosteum. An image intensifier may be used to get a lateral image to show a well orientated pocket.

    The medial plate is inserted into the submuscular pocket.This is done using either the aiming block with or without the introducing handle the plate is now slid into place.

    The medial plate position should be checked with the image intensifier.In this case a single screw distally has been introduced to oppose the plate to the bone distally

    In the same manner as was used on the lateral side the medial plate is locked using a small incision proximally and threaded locking guides.I prefer one short incision to a series of percutaneous stabs as these can often be ragged.

    Threaded locking guides are used to drill proximally.
    Drill sleeves should be always used for all locking screws. The 3.1mm drill is used for the 4mm locking screws, and if the cortex is very tough then a tap can also be used to ease screw placement. Screw length can read off the drill in the orange drill sleeve, but I find it preferable to use a depth gauge as the drill measures I find not to be so accurate as it can be hard without screening to know where the tip of the drill lies. The depth gauge is a “get what you read” gauge in other words no length extraction is needed. Again a torque screwdriver is used to 2.5Nm, and the screws never introduced under power.

    The distal medial plate is fixed using a mixture of locking and non-locking screws as was the case antero-laterally.
    It can be seen that the comminuted metaphysis is bridged in this construct. This area of bone, like all metaphyses, has good healing potential and this would be hampered by stripping the periosteum off the bone here which might occur if non-bridging techniques were employed.

    Wound closure with interrupted suturesI like to close the wounds with interrupted sutures to minimise the risk of a retained haematoma. The procedure was carried out without a tourniquet so bleeding was well controlled intra-operatively but already damaged soft tissue tolerate a haematoma very poorly in pilon fractures and wound breakdown is a very severe complication with poor outcomes. I dress the wounds with petroleum gel gauze and then orthogauze.

    A well padded plaster backslab with plenty of wool wrap is used to maintain ankle joint position and facilitate wound healing for two weeks.

    Radiographs at 6 weeks show maintenance of fixation in a light weight cast. Healing is minimal at this stage as would be expected


    Lateral view at 6 weeks, position remains unchanged on this view too.

    The limb at 12 weeks shows wounds well healed
    Scarring is minimal in the skin at 12 weeks as these photographs demonstrate

    At 12 weeks also there is little in the way of swelling. He has been weight bearing in a walking boot for the preceding 6 weeks (ie weeks 6 to 12)

    At 12 weeks post operative radiographs show good evidence of bone healing within the metaphysis of the tibia. There is no pain on stressing the tibia, the wounds are well healed and so at this point weight bearing out of the boot is started

    Operation – 3
    Post Operative

    The limb is rested in a plaster backslab in neutral for two weeks.
    Patients are provided with thromboprophylaxis according to a risk assessment – in our institution we use a Thrombin Xa inhibitor (Rivaroxaban) until weight bearing or range of movement is effective. In a complaint patient I will remove the cast and take out the sutures at 2 weeks and commence non-weight bearing range of movement exercises supervised by the physiotherapists. In a non-compliant case then the cast is kept on for 6 weeks.
    Weight bearing is gradually commenced in either case for 6 weeks with full weight by 12 weeks. Fracture clinic reviews are at 2, 6 and 12 weeks. Final review is usually at 6 months.
    Consideration must be made of course of the associated injuries (open femoral fracture in this case) in terms of weight bearing status.
    Images at 6 and 12 weeks are taken to ensure no hardware failure and to confirm the ongoing stability of the fracture and fixation.

    Recommended Reading

    Topliss CJ, Jackson M and Atkins RM.Anatomy of pilon fractures of the distal tibia. J Bone Joint Surg (Br). 2005 May;87(5):692-7.
    In a series of 126 consecutive pilon fractures, we have described anatomically explicable fragments. Fracture lines describing these fragments have revealed ten types of pilon fracture which belong to two families, sagittal and coronal. The type of fracture is dictated by the energy of injury, the direction of the force of injury and the age of the patient.
    Sirkin M, Sanders R, DiPasquale T, Herscovici D., Jr A staged protocol for soft tissue management in the treatment of comples pilon fractures. J Orthop Trauma. 2004;18:S32–S38
    A key paper demonstrating the benefit of delayed ORIF where there was soft tissue damage. Although the technique used would now be considered out moded (using a lateral plate and a monolateral fixator) they clearly showed the importance of soft tissue respect and that of delayed definitive care.
    Watson JT, Moed BR, Karges DE, Cramer KE. Pilon fractures. Treatment protocol based on severity of soft tissue injury. J Clin Orthop Relat Res. 2000;375:78–90
    These authors emphasized that minimally invasive separation of soft tissue not only protects the blood supply of the fractured bone but also provides indirect reduction. Watson suggested choosing the surgical approach on the basis of the condition of the injured soft tissue, and recommended the use of limited exposure and stabilisation with small wire circular external fixators.
    Xianfeng He, Yong Hu, Penghan Ye, Lei Huang, Feng Zhang and Yongping Ruan. The operative treatment of complex pilon fractures: A strategy of soft tissue control. Indian J Orthop 2013 Sep; 47(5):487-492
    The authors review 36 cases of ORIF with the emphsis on soft tissue care operatively and the use of vacuum assisted wound dressings. They show good results and low complications. This is a modern approach to ORIF of Pilon fractures.

    Reference

    • orthoracle.com

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