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Talar fracture- Fixation of talar body and talar neck fractures via medial malleolar osteotomy

    Overview

    Learn the Talar fracture: Fixation of talar body and talar neck fractures via medial malleolar osteotomy surgical technique with step by step instructions on OrthOracle. Our e-learning platform contains high resolution images and a certified CME of the Talar fracture: Fixation of talar body and talar neck fractures via medial malleolar osteotomy surgical procedure.
    In general terms, fractures of the talus can be broadly divided into low and high energy injury patterns. Examples of low energy fractures include avulsions, osteochondral fractures and talar process fractures. High energy injuries will either lead to the relatively uncommon situation of talar extrusion or, more frequently, fracturing of the neck or body of the talus. In these instances, the talar fracture is often associated with other injuries that may need more urgent treatment, but equally a significant proportion of these injuries will need emergent care because they are open.
    The mechanism of injury in talar neck fractures is forced ankle dorsiflexion in combination with forefoot supination. Body fractures often occur in a similar vein but have the additional element of axial loading and the hindfoot being in varus or valgus on impact. A fracture of the talar body is differentiated from a talar neck fracture by the presence of a primary coronal plane fracture line on the inferior surface of the talus involving the posterior facet of the subtalar joint. In reality, our experience in Sheffield is that invariably, body fractures also involve the neck of the talus.
    It is well appreciated that both talar fracture types are associated with a poor outcome but the prognosis of displaced body fractures is uniformly poor, even when compared to talar neck fractures. It is really important not to lose sight of the fact that there are two reasons why this is the case. Firstly, the injury to the bone (and its vascular supply) and soft tissues. This has already occurred to the patient and cannot be undone. Therefore, the second reason for poor outcome is down to the further iatrogenic insult from the surgical treatment. As a surgeon, you have control of this latter cause. Therefore, careful planning is required before embarking on any surgery and this planning needs you to consider which of the key vessels that give the talus its notoriously poor blood supply have been compromised by the initial injury. Remember that 60% of the surface of the talus is covered in articular cartilage. The remaining forty per cent is occupied by joint capsular reflections and ligament insertions and that there are no tendon origins or insertions. The vascular supply to the talus arises from anastomoses from the anterior tibial artery (36%), the posterior tibial artery (47%) and the peroneal artery (17%) with relative contributions of flow indicated in brackets. Inferiorly, there is a significant supply from the anastomoses within the tarsal canal and medially through branches lying within the deep deltoid ligament.
    In the following case, a 60 year-old male fell 10 feet from a ladder onto concrete. He sustained a closed injury to his left talar neck and body and the soft tissues were not threatened by any dislocated fracture fragments. This was an isolated injury.














    Indications

    Indications
    An acute displaced fracture of the neck and/or body of the talus. With fractures purely involving the neck of the talus, the subtalar joint is affected in Hawkins’ types 2, 3 and 4 as the joint dislocates in these injuries. With fractures of the body of the talus, fracture lines invariably propagate between both the ankle and subtalar joints. In both fracture patterns, the subtalar joint is involved and therefore this means that post-traumatic arthrosis is a possible outcome. Additionally, with increasing severity of injury with neck, body or combined fractures, there is potential compromise to the vascularity of the talus and pre-disposition to avascular necrosis of the talus.
    Traditionally, it has been taught that talar neck fractures should be treated with a combined anteromedial and anterolateral approach. This has been to afford the optimal access to the talus to achieve anatomical reduction but, by not considering the vascular injury, may not be the best mantra for limiting the chances of AVN. Therefore, I rarely would advocate using both these incisions. My feeling is that it is worthwhile considering which is the most comminuted side of the talar neck as operating through this side will cause little further compromise to the remaining vascularity. Also given that almost a quarter of these fractures are associated with a medial malleolar fracture, it is worthwhile considering the use of the existing fracture line as a created osteotomy for a surgical approach.

    Symptoms & Examination
    A significant percentage of these injuries will be open and/or associated with other injuries. In an unconscious or ventilated patient the injury of the talus should be diagnosed during the “exposure” section of Advanced Trauma Life Support principles but can easily be missed in the absence of foot deformity or breaches to the soft tissue envelope. In a conscious patient, the foot will be very painful and bearing weight will not be possible. In an obviously dislocated talus, closed reduction techniques should be performed in emergency room if there is compromise to the soft tissues. The neurovascular status of the limb should also be assessed and noted. The ankle should be splinted in a temporary cast for analgesia and to rest the soft tissues. Any open fracture should be managed with lavage, reduction, splint age and a dose of antibiotic therapy. In the event of compromised skin from an irreducible injury, emergent access to theatre should be arranged to enable further closed or open reduction manoeuvres. In an experienced emergency department, it is worthwhile spending the extra 5 minutes to obtain a CT for the information that it provides in planning the reduction.
    Investigation
    Plain radiographic imaging is the usual initial mode of imaging. Dependent upon the severity of the injury and the presence of deformity, these plain film images can be difficult to interpret in a meaningful manner. My personal view, and that of my colleagues in Sheffield, is that a CT scan is mandatory. This helps detail the fracture pathoanatomy and aids in planning surgical approach and methods of fixation. MRI is of little benefit in assessing these acute injuries.
    Initially, Hawkins devised a classification of talar neck fractures into three discrete groups of increasing severity. In type one injuries, there is simply a minimally displaced fracture across the neck of the talus. In type two injuries, the posterior facet of the subtalar joint is subluxated/dislocated. In type three injuries, the fracture is associated with both the posterior facet of the subtalar and ankle joint subluxation/dislocation. A fourth group was later added by Canale and Kelly which represents the most severe fracture pattern. As well as both subtalar and ankle joint subluxation/dislocation, there is dislocation of the head of the talus from the talo-navicular joint. This has been universally appreciated to be associated with a poor clinical outcome. The Hawkins/Canale classification system is useful as it reflects injury severity which is useful when counselling the patient about prognosis and their chance of functional recovery. A universally accepted classification system for talar body fractures does not exist and moreover, there is no classification system for combined fractures of the body and neck of talus.
    Non-operative intervention
    Non-operative intervention has a role to play when there is minimal displacement of fracture fragments. Equally, in very polytraumatised or poorly patients, it may be that the risks of surgery far outweigh the benefits. This is a very rare occurrence.
    Operative alternatives
    Apart from in the simplest fracture patterns, open reduction and internal fixation is the mainstay of managing these injuries. The aim is to reconstruct the shape of the talus with minimal disruption of the soft tissue envelope.
    Contraindications
    Be very aware of the red, swollen and unstable foot with little pain. This presentation should raise the suspicion of a neuropathic foot undergoing a Charcot process.
    Open incisions to the traumatised foot in the presence of diabetes, vascular disease or metabolic compromise from steroid treatment are relative contra-indications for surgical intervention.

    Setup

    The patient is positioned supine on the operating table and may require a sandbag under the ipsilateral buttock so that the foot points vertically towards the ceiling which allows dual incision access. For pure medial access, the sandbag may be best placed under the contralateral buttock and for isolated lateral access, the patient can be placed in a more formal lateral position. Fluoroscopy should be available with an image intensifier and a trained radiographer.

    Appropriate antibiotics are administered and a thigh tourniquet and exclusion drape are applied. The limb is prepared with Chlorhexidine from toes to tourniquet.

    Operation – 1

    The pre-operative A-P radiograph of the ankle with a temporary plaster of Paris applied for splintage. There is a clear bony anomaly in the medial talus but very little useful information can be gleaned from this image.

    The plain lateral radiograph shows the discontinuity between the body and the head of the talus with malrotation through the neck fracture.

    This malrotation is clearer on the CT. However, it is clear that there is a multi-fragmentary set of fracture lines within the body of the talus.

    The axial CT cuts through the body of the talus show a “Mercedes Benz sign” fracture of the body of the talus with a coronal split obscured by the medial malleolus. There is a sagittal split in the anterior body of the talus.

    Further axial CT cuts reveal the extent of medial comminution around the neck of the talus but a relatively simple fracture extension onto the lateral talar neck. It is most common to observe medial comminution of the neck of the talus because either the hind foot is forced into varus or the mid foot is supinated at the point of impact.

    It is clear that this combined fracture to the neck and body of the talus cannot be classified by Hawkins system. The medial comminution of the neck of the talus, combined with the displaced fracture lines of the body lying deep to the medial malleolus suggests that the medial side of the talus has been more severely injured and will have had more potential injury to the medial blood supply to the bone. Additionally, it is important to try and prevent the medial border of the talar neck to shorten with, or following, fixation in order to prevent a varus malunion.
    Weighing up all of this information, I decided to access the talus through a medial approach and that the best access to both the body and neck of talus would be through a medial malleolar osteotomy. This affords the best view of both areas and, in a sufficiently executed osteotomy allows optimal access to instrument the fractures.

    Position the patient on the operating table to gain access for planned surgical approach, supine and towards the bottom and edge of the table.This shows the patient positioned on the operating table. The heel is close to the edge of the table so that I can sit and easily reach the foot for the duration of an operation that can be lengthy! Equally, the foot should not lie over any of the structural metalwork in the frame of the operating table so that fluoroscopy can be easily performed.

    The outline of the medial malleolus is marked on the skin together with the planned curved skin incisionFirstly, note the yellow discolouration from the bruising associated with the injury almost a week after the patient fell.
    The U-shaped markings on the skin outline the medial malleolus [A] with an anterior curve [B] onto the anterior joint line of the ankle. My planned skin incision is curved to raise a skin flap that will allow access to the tibial plafond for the medial malleolar osteotomy and also access to the medial aspect of the talar neck.

    Identify the tibialis posterior tendon and mobilise it to free it from the medial malleolusThe skin flap is elevated and retracted with care using cats paw retractors. Then the posterior aspect of the medial malleolus is identified and an incision is made in the reticular fibres investing the tendon of tibialis posterior [A]. This is crucial because a retractor will be placed into this interval to protect the tendon from the saw blade during the osteotomy.

    Define and expose the anterior ankle jointThe next step is to clearly define the anterior ankle joint and an arthrotomy is performed. In this photograph my forceps lie in the ankle joint. At no point should any dissection be performed inferior to the medial malleolus as preservation of the fibres of the deltoid ligament is paramount to preserving vascularity.

    Define the apex of the planned malleolar chevron osteotomy using the image intensifierI choose to perform a chevron shaped osteotomy. This is because I find it easiest to fully re-approximate the osteotomy at the point of closure because there is a clear geometric form that can be readily visualised and it is stable in configuration. Alternatives include (1) a straight line cut, but this is an inherently unstable osteotomy prone to malreduction and (2) a vertical “step-cut” which is still a chevron but performed in the sagittal plane. I have never needed to try this latter option.
    A frequently observed mistake is to see a transverse osteotomy at or below the level of the tibial plafond which is no use as an approach and is more prone to non-union.
    Using a K-wire, the apex of the chevron osteotomy is identified on the image intensifier. I like to position the apex to lie at the level of the physeal scar.

    Mark the apex of the chevron osteotomy on the periosteum of the medial malleolus.Using a pen, the apex of the planned chevron osteotomy is marked on the periosteum.

    Incise the periosteum along the limbs of the planned chevron osteotomyIn preparation for the saw cuts, the periosteum is incised in a shallow chevron shape and gently reflected away from site of the osteotomy.

    Insert two guide wires from the tip of the medial malleolus into the distal tibia and check the position of the guide wires across the planned osteotomy. At this stage, two Stryker ASNIS guide wires are introduced through the tip of the medial malleolus in order to commence the pre-drilling of the fixation for the osteotomy.
    I use the titanium Stryker ASNIS screws because, if at any point in the future, I want to image the talus with MRI, the artefact from the hardware is minimised compared to using stainless steel implants.

    The position of these wires is checked on fluoroscopy to lie at the apices of the osteotomy in all planes. This is to apply good lag screw fixation at re-apposition of the osteotomy.

    Pre-drill over the guide wires before performing the osteotomyThe wires are then over-drilled so that 4mm part-threaded cannulated ASNIS screws can be applied across the osteotomy.

    Pass a K-wire at the apex of the chevron osteotomy At the apex of the planned chevron osteotomy, I pass a wire parallel to the ankle joint line. This will act as a reference for the use of the oscillating saw.

    With an oscillating saw start the anterior and posterior chevron ostetomy saw cutsHaving removed the ASNIS guide wires, the oscillating saw is applied to the anterior and posterior aspects of the medial malleolus. I am cutting the tibia to exit the anterior and posterior tibial plafond proximal to the ankle joint to maximise the exposure of the body of the talus.

    Note how the tibialis posterior tendon is religiously protected from the saw blade. It is useful to use the etch lines on the saw to monitor the depth of saw cut.

    From an anterior approach, use a fine osteotome to help with completing the osteotomyHaving used the etch lines to plan the depth of the osteotomy, in this photograph I am using a fine osteotome in the sagittal plane to start to complete the osteotomy.

    The osteotomy is completed by passing a pair of Hibbs osteotomesA pair of Hibbs osteotomes is placed with one in each limb of the chevron cut. With the osteotomes at full depth, the pair are pulled simultaneously in a plantar direction to complete the osteotomy.

    With completion of the osteotomy, the medial malleolus is mobilised on the fibres of the deltoid ligament.It is usual for soft tissue attachments to be released with a blade in order to achieve full retraction and the optimal view of the body of the talus. At this point, the medial malleolar fragment is rotated in a plantar direction on the intact fibres of the deltoid ligament.

    Insert two 2mm K-wires and apply a Hintermann self-retainer spanning across from the tibial plafond to the reflected medial malleolus.It is best to provide stable retraction of the osteotomy during the reconstructive phase of the surgery.

    The best placement of the 2mm K-wires is best appreciated on this fluoroscopic image. One wire is placed in the distal tibia [A] and the other is placed axially along the medial malleolus so that it does not add another insult to the articular surface [B]. The self-retainer is then held open with the ratchet mechanism [C].
    Note the clear access that this osteotomy allows to the medial shoulder of the talar body. In my opinion, smaller osteotomies provide the worst of both worlds: small osteotomy fragments that may prove difficult to unite and a limited view with an inability to easily instrument the shoulder of the talus. By osteotomising onto the plafond, this should allow a better chance of union and gives superior surgical access.

    Apply lag screw fixation to the body of the talus once it has been reduced.Given the fracture lines within the body of the talus were less displaced, I decided to reconstruct the body first. Here I have already applied a guide wire across the sagittal split in the anterior aspect of the body of the talus. I am over drilling with a view to applying a Standard Acutrak screw to compress this fracture line. The rationale for using the Acutrak system is that the screws are headless and will lie deep to the articular surface.

    The positioning of the buried Acutrak screws is checked fluoroscopically. It is clear to see that the heads of the screws lie within bone – a conscious effort should be made so that they are placed very deep to the articular cartilage.

    Operation – 2

    Position a K-wire in the head of the talus in preparation for reducing the talar neck fractureA second Acutrak screw was then introduced from the large postero-medial body fragment into the lateral aspect of the talar body. This achieved good compression. I was happy that the body was well-reconstructed and that it was now intrinsically stable.
    In this photograph, I am starting the process of reducing the malrotated talar head by accessing across the neck of the talus. In the absence of the osteotomy, access across the neck of the talus with your index finger is restricted and yet this is possibly the most crucial step in the reconstruction of this talus.
    You can see that I have already pre-positioned a stout K-wire in the head of the talus to be ready to hold the restored relationship between the head and body of the talus after my reduction manoeuvre and advancement of this wire.

    Apply joystick K-wires and remove Hintermann retractorThere are two things that I have done to try and optimise the ability to reduce the head of the talus onto the body. You can see that I have removed the Hintermann self-retainer and its wires. This is because the tension across the joint may hinder the reduction manoeuvre. Secondly, I have passed a 2mm K-wire transversely across the head of the talus to act as a joystick. This way, I can rotate the head of the talus into position and hold it there whilst I advance the K-wire holding the reduction.
    Finally, I have made a window immediately posterior to the tibialis posterior tendon so that I can achieve the correct angle to advance a guide wire along the axis of the reduced talus to apply definitive fixation.

    Check your reduction on image intensifierThis D-P view of the hindfoot from the image intensifier clearly shows the two Acutrak headless screws lagging the talar body fragments.
    In addition, the joystick K-wire can be clearly seen in the head of the talus [A]. The wire spanning the head of the talus to the body holding the reduction is also clearly seen [B]. The guide wire for the 5mm ASNIS screw can be seen passing from the postero-medial aspect of the talus to the antero-lateral aspect of the talar head [C].
    There are two other key observations. Firstly, I am happy that I have achieved reduction because the contour of the lateral aspect of the talar neck is restored [D]. Secondly, it is clear to see that there is a defect in the medial aspect of the talar neck as a result of the comminution [E].

    Apply further fixation across the neck of the talusThe 5mm ASNIS screw was then passed into the talus and achieved good compression. Although this stout screw is axially positioned in the less comminuted aspect of the talus, it is not sufficient fixation to control rotation across the talar neck nor to provide sufficient protection against the medial talar neck from collapse. I could have applied a fully threaded screw across this K-wire which would have afforded more protection against collapse but would not have applied compression across the fracture fragments.

    Application of locked plating to comminuted side of talar neckIn order to control rotation across the talar neck and provide sufficient protection against the medial talar neck from collapse, I have added a Stryker VariAx hand plate to span the defect noted on the image intensifier. This has been contoured across the defect by bending the plate accordingly to fit. It is important that the proximal end of the plate does not impinge upon the articular surface of the medial malleolus. The plate is applied with 2.3mm locking screws.

    Re-approximate the medial malleolar osteotomyThe next step is to reduce the medial malleolus. This is easily achieved and the 4mm ASNIS guide wires can be positioned across the osteotomy.
    A tip here is to pass the wires through the drill holes in the cut surface of the malleolus to pierce the deltoid fibres rather than blindly searching for the drill hole entry points embedded in the deltoid substance.

    Apply lagged screws across the medial malleolar osteotomyThe 4mm ASNIS part-threaded cannulated screws and washers are then used to secure the osteotomy.

    Check your fixation on image intensifier The D-P view of the talus shows all of the hardware in situ. Note the conjured Stryker VariAx hand plate spanning the medial talar neck.

    The A-P ankle view showing the fixation.

    The lateral view of the ankle showing the restored profile of the body relative to the head of the talus.

    Deep closure repairing the sheath of tibialis posterior followed by skin closureThe deep layers of the approach are repaired with 2/0 vicryl. It is important to make sure that the tibialis posterior tendon is stable by repairing the retinaculum. the skin is closed with 3/0 monocryl.
    I apply a Jelonet dressing to the wound followed by dressing gauze and orthopaedic wool. Back and stirrup plaster of Paris slabs are then secured with crepe bandage with the foot and ankle in a plantigrade position.

    Post Operative

    The patient is placed in a below the knee back slab for the first two weeks after surgery. At two weeks, the wounds are inspected and re-dressed and a complete, lightweight below-the-knee cast is applied for a further four weeks. Weight bearing is not permitted for the first six weeks after surgery and in my practice, rivaroxaban is prescribed for this duration to prevent thrombo-embolic events.
    At six weeks, plain radiographs are used to assess whether the medial malleolar osteotomy has united. If it has, then the patient can start bearing weight in a walker boot for a further 6 weeks. If it hasn’t united then I would maintain the period of cast immobilisation for a further 4 weeks and perform further plain radiographs.
    If at 6 weeks the osteotomy looks to have healed, then physiotherapy can be started to work on the ankle, subtalar and talo-navicular joint range of motion.

    At 12 weeks, further plain radiographs are useful. This is to check for Hawkins’ sign. Hawkins described subchondral osteopenia on the A-P ankle radiograph (not the lateral view) as a positive sign of revascularisation. It represents bone turnover in this region. Some authors rely on this sign to govern when the patient can start to bear weight but in some cases of body and neck fractures, this sign may never appear. At some point a pragmatic approach is required which, in my view, is that the presence of Hawkins’ sign is good news but the absence is not necessarily bad news and the patient will need to start bearing weight at some point! Therefore, all of my patients will be bearing weight by 12 weeks regardless of the the radiographic appearances. One could argue that further imaging modalities could help govern the vascularity of the post-operative talus. Certainly, I have a low threshold for using CT to look for union but some authors advocate MRI to judge for talar viability. This necessitates the use of titanium implants to minimise artefact. For me the key is the union of the osteotomy as this provides stability to the ankle to allow weight bearing.

    Recommended Reading

    Vallier HA, Nork SE, Benirschke SK et al. Surgical treatment of talar body fractures. J Bone joint Surg 85A: 1716-1724, 2003.
    This paper presents a large series of body fractures from a major trauma centre. They conclude that combined talar neck and body fractures have the highest chance of post-traumatic osteoarthritis. Collapse of the body of the talus was almost universal in open fractures who went on to develop AVN. Almost 90% of body fractures had the sequelae of AVN or arthrosis.
    Vallier HA, Nork SE, Barei DP et al. Talar neck fractures: results and outcomes. J Bone Joint Surg 86A: 1616-1624, 2004.
    From the same institution and in the same year, this study looked at the outcomes from talar neck fractures. It confirmed a linear relationship of AVN with increasing Hawkins grade but also that comminuted and open fractures were most likely to result in post-traumatic osteoarthritis.
    Prasarn ML, Miller AN, Dyke JP et al. Arterial anatomy of the talus: A cadaver and gadolinium-enhanced MRI study. Foot Ankle Int 31(11): 987-993, 2010.
    This study is helpful because rather than describe what the patterns of vascular supply are, it quantifies the relative contribution of the three main arteries: 47% from the posterior tibial artery, 36% anterior tibial artery and 17% from the peroneal artery.
    Chen H, Liu W, Deng L, Song W. The prognostic value of the Hawkins sign and diagnostic value of MRI after talar neck fractures. Foot Ankle Int 35(12): 1255-1261, 2014.
    This paper confirmed that Hawkins sign was more likely to be present in lower energy talar neck fractures. In the higher grade injuries the incidence of AVN was about 50:50 and that MRI at 12 weeks was of use in determining vascularity in the absence of radiographic Hawkins sign.
    Vints W, Matricali G, Geusens E et al. Long-term outcome after operative management of talus fractures. Foot Ankle Int 39(12): 1432-1443, 2018.
    With over 9-year mean follow-up, this study confirms the importance of accurate anatomical reduction in trying to lessen the degree of post-traumatic osteoarthritis but that the fracture pattern was also a significant influencing variable in outcome.


    Reference

    • orthoracle.com

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