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Medial column arthrodesis for a midfoot Charcot rocker-bottom deformity- Wright Salvation system

    Overview

    Learn the Medial column arthrodesis for a midfoot Charcot rocker-bottom deformity: Wright Salvation system surgical technique with step by step instructions on OrthOracle. Our e-learning platform contains high resolution images and a certified CME of the Medial column arthrodesis for a midfoot Charcot rocker-bottom deformity: Wright Salvation system surgical procedure.
    Charcot neuro osteoarthropathy is a devastating complication of peripheral neuropathy, primarily effecting the lower limbs. Its commonest cause in western populations currently is Diabetes Mellitus. Its acute presentation is characterised by a combination of destructive features including fracture, dislocation, severe loss of bone density and associated soft tissue swelling and often ulceration. It has a complex etiopathogenesis. Neuro-traumatic mechanisms with activation of complex biochemical pathways coupled with autonomic dysfunction on a background of cumulative microtrauma are generally thought to be the precipitating factors. If neglected, patients eventually present with severe deformity which is either fixed or unstable. This can lead to ulceration due to an abnormal weight bearing profile of the sole of the foot and can be a cause of loss of limb. Observational studies following Charcot patients recurrently reflect that limb loss is a poor prognostic indicator.
    The traditional classification for the stages of Charcot arthropathy has been Eichenholtz’s system which is based on clinical and radiological evaluation of the limb in question. Originally described in 1966 by Eichenholtz in 3 stages (Eichenholtz SN. Charcot Joints. Springfield, IL, USA: Charles C. Thomas; 1966), a third stage, 0 ,was added in by Shibata et al(The results of arthrodesis of the ankle for leprotic neuroarthropathy. Shibata T, Tada K, Hashizume CJ Bone Joint Surg Am. 1990 Jun; 72(5):749-56.)
    Treatment of Charcot disease is complex difficult frustrating and unpredictable. The deformities caused by this disease are often multi-level and multi-axial and operative planning is difficult upon the background of ulceration, osteomyelitis and bone destruction. The importance of timing of the operation cannot be overemphasised as in the earlier phases of the disease operation can have devastating sequlae secondary to almost unfixable bone and unclosable soft tissues.
    It is generally accepted that any surgical intervention for stabilisation or deformity correction is best done after the stage of repair and remodelling are complete (Eichenholtz stage 3). It is also of paramount importance that the deformity correction is done when any ulcers are rendered infection free or healed for fear of devastating infection which can often lead to loss of limb. Earlier operation is though on occasion required, in particular in the context of an uncontrollable and progressing deformity or impending soft tissue breakdown.
    Choosing the method of stabilisation is equally important as conventional methods of treating these deformities fail regularly both due to altered bone healing with the production of abnormal collagen as well as non-compliance with non weight bearing by patients who can’t feel their feet.
    The choice of hardware in fixing these difficult fusions is also of significance as conventional hardware, such as small fragment plates and screws, are almost sure to fail. Specially designed implants are now available for use which utilises robust designs with highly secure fixation screws, low profile yet strong and malleable plates as well as the use of intra-medullary beams and bolts which allow compression as is found with the Wright Medical Salvation system of fixation. It is also essential to use bone stimulation techniques including the use of osteogenic materials such as bone graft, bone marrow aspirate concentrates, Bone Morphogenic Protein, external and internal bone stimulators. The success of the operation depends on thorough preparation, robust fixation and protracted protection postoperatively.
    External fixation is also used with innovative techniques such as minimally invasive surgery to create a treatment algorithm that is specifically of use in patients with poor skin or peripheral vascular disease. It is the case that many of these procedures are refusions of failed operations and the quality of skin is often compromised with multiple previous incisions where external fixation techniques with fine wires can be of great use.


    Indications

    INDICATIONS
    Medial stabilisation with arthrodoesis of multiple joints along the medial ray of the foot is best reserved for significant deformity arising from Charcot or other destructive conditions such as infection, post traumatic deformity and instability, severe adult acquired flat foot with arthritis and instability, the rocker bottom foot due to various causes, and occasionally congenital deformities of the medial ray
    SYMPTOMS & EXAMINATION
    The classic patient is a diabetic patient with reasonable peripheral circulation of longstanding with almost universally a history of peripheral neuropathy and Charcot arthropathy. Deformity is the primary indication and can be either fixed or unstable and dynamic deformity. The patient may present with or without an ulcer. The presence of an ulcer is not a contraindication for surgery as sometimes the only way to heal the ulcer is to correct the deformity. It is however of paramount importance that the ulcer is sterile and proven so with deep tissue samples showing negative microbiology. Many patients describe pain which is more of a deep seated ache and is seemingly different to somatic pain felt by patients with normal sensation. Many patients will have presented previously with their symptoms of acute or sub-acute Charcot ( Eichenholtz stages 1 &2) or may present with infections as a result of ulceration and subsequent tissue loss. many of them present with indolent ulcers which haven’t healed in spite of extensive treatment by other health care professionals such as podiatry and tissue viability specialists. There is sometimes a history of osteomyelitis is not uncommon.
    Examination is extremely important so that subtle features of instability, deficiency of tendon mechanisms, peripheral neuropathy, occult deformity such as equinus, and circulatory insufficiency are not missed.
    Local examination should include mapping of sensation in the foot as well as assessing circulation. The use of the 1 gram Monofilament to assess sensation, tools to assess position and vibration sense and a hand held Doppler ultrasound probe to assess circulation is almost indispensable as part of routine examination of the diabetic foot. The various joints in the foot are carefully examined for instability or fixed deformity. The sole of the foot is also of great importance as bony prominences in the other rays may also have to be dealt with to avoid a recurrence of ulceration. If an ulcer is present then a careful assessment and classification of the ulcer is essential. This will have to be coupled with taking deep tissue specimens for microbiological culture to establish the sterility of the ulcer before considering operation. Joints such as the ankle joint that are seemingly not involved in the deformity should also be carefully examined. The commonest finding is that of equinus with true Achilles tendon contracture. This is as a result of a lax short and adynamic tendon as the foot suffers a midfoot break often in the 1st tarso-metatarsal, naviculo-cuneiform, or talonavicular joint which over a period of time leads to shortening and contracture of the Achilles tendon. This results in the lack of range of movement in the ankle joint for propulsive ambulation. If this equinus is not identified it is almost certain to cause the procedure to fail as the fusion sites will suffer an enormous amount of stress through the mid whilst walking leading to failure of fusion even months after the operation or the emergence of instability or deformity in other joints in the midfoot. It is also necessary to examine the rest of the limb to ensure other parameters such as the anatomic and mechanical axis of the limb or not abnormal so that fusion will not result in an abnormal position of the weight-bearing foot which is disastrous as the foot no longer has the ability to compensate for the position.
    One must not forget taking into consideration other co-morbidities in the patient and optimisation of renal and cardiac function is very important. The multidisciplinary team approach is almost indispensable with optimal treatment of the glycemic status playing a pivotal role in post operative management of the patient. It is well recognised that optimisation of the Hb1Ac is extremely important prior to operation and may well play a major role in the success of the operation and avoiding complications.
    IMAGING
    Plain radiographs of the weight bearing foot and the ankle in Anteroposterior and lateral projections, subtalar views (Broden) special views such as the Salzman view are required and in the absence of infection are most useful in determining the nature of the deformity. This may be supplemented by CT and/or MRI if additional information about soft tissues or 3D reconstructions are required for the purpose of reconstruction.
    If there is severe deformity then I would almost always ask for a vascular surgical opinion which often includes a CT angiogram as the medial neurovascular bundle is often severely distorted by the deformity. If there is a history of past infection then a White Cell Labelled Scan is very useful to assess the presence of residual or occult infection.
    During the course of examination the process of consent should also begin. Planning the appropriate operation and explaining in detail the various options available to the patient following examination is extremely important as the complications are life changing including limb loss. Non union rates are high as well as problems with metalwork and wound healing and this should be carefully highlighted to the patient
    CLASSIFICATION
    The Modified Eichenholtz Classification is the one most commonly used to stage patients and provide a broad idea on the timing of surgical treatment. The Eichenholtz classification has not been validated though is in common usage. It also has its limitations in that it does not take into account the anatomic site or patient co-morbidity which are also important for decision making in the treatment of Charcot disease.
    Stage 0 (prodromal)
    Clinical: Swelling, erythema, and increased limb temperature. Xray: Normal radiographs.
    Stage 1 (Acute)
    Clinical: Swelling, erythema, increased limb temperature and Ligament Laxity. Xray: Osteopenia, fractures, fragmentation and subluxation.
    Stage 2 (Coalescence)
    Clinical: Decrease in swelling, limb temperature and oedema. Xray: Callus formation, fracture healing, sclerotic areas.
    Stage 3 (Consolidation)
    Clinical: Normal colour temperature and girth. Fixed or unstable deformity. Xray: Remodelling of deformity, mature callus, Fixed deformity
    Other classifications including the Sanders and the Brodsky classification use the anatomic site of bony destruction to describe the types of Charcot arthropathy. These are also limited in their ability to either prognosticate or plan treatment. Lew Schon’s classification further subdivides midfoot Charcot into sites with the most significant involvement. He also stages the condition based on the severity of deformation and collapse in the sagittal plane of the foot.
    However none of the classifications are comprehensive and it is generally the case that Eichenholtz classification continues to enjoy the widest usage in current diabetic practice.
    ALTERNATIVE OPERATIVE TREATMENT
    Fine wire frame stabilisation of the fusion can also be used and when done with minimally invasive osteotomy and sequential correction of the deformity is a biologically friendly method of correction of deformity particularly in the presence of poor soft tissue or vascular compromise.
    NON-OPERATIVE MANAGEMENT
    This largely consists of orthotic devices or custom made footwear to accommodate the deformity if fixed or to correct it if it is flexible. This can be employed in patients whose deformity is braceable, elderly patients or patients whose compliance post surgery is poor. If the deformity is fixed it may be possible to “de-profile” the foot by resection of bony prominences.(exostectomy).
    CONTRAINDICATIONS
    The main contraindication is the presence of active infection , severe peripheral vascular insufficiency or a lack of confidence in the compliance of the patient post operatively. The procedure must be approached with caution in patients with severe concomitant systemic disease such as renal disease, cardiac and cerebral disease. As a rule the operation is contraindicated in patients with a poor glycaemic control as evidenced by high blood sugars and a high HbA1C as it has significant implications on wound healing post operatively as also the success of fusion.

    Setup

    I do not use a tourniquet for this operation in a diabetic for fear of injuring the somewhat tenuous and often calcified vasculature. If I am confident that the use of the tourniquet will not compromise the patients vascular supply then i would elevate and exsanguinate the limb and use and above knee tourniquet. The patient is placed supine without a sandbag as most of the operation is conducted from the medial side. If a Tendo-achilles lengthening is required I use the percutaneous 3 cut lengthening as was done in this patient. I use diathermy for haemostasis.
    The limb is prepped to above the patella as this is required to access the patella for the purposes of assessing the alignment of the limb during and at the end of the operation. Bone graft may also be taken from the proximal tibia. A sand bag is placed initially under the contralateral buttock to make medial access easy if required.

    Operation – 1

    The lateral radiograph shows the deformity in the sagittal plane with severe plantarflexion of the talus, loss of calcaneal pitch and plantar prominence.
    This deformity was unstable and resulted in a plantar medial ulcer over the prominent talar head

    The Antero-Posterior radiograph of the weight bearing foot shows the deformity in the axial plane with uncovering of the talar head peritalar subluxation and deformity of the foot distal to the talus in supination and abduction. There is severe shortening of the lateral column as a result.

    This photograph shows the deformity of the foot with supination and abduction. There is also a healed plantar medial ulcer seen. This was treated with aggressive debridement and a total contact cast preceding surgery. Swabs were taken immediately prior to the operation to ensure that the the skin in this area was sterile.
    Remnants of the callus, which was repeatedly debrided, are also seen surrounding the ulcer

    The limb is positioned as shown with free access to the medial and dorsal aspects of the foot.
    Important landmarks including the anterior tibial crest, the medial malleolus, and the navicular are drawn in indelible ink to act as the landmarks for the approach.
    A tourniquet was not used, as is frequently the case in diabetic foot and ankle surgery. The large arterial vessels can be significantly atherosclerotic in such patients and are easily compromised by the direct pressure of an applied tourniquet. In addition the acute and significant correction of bony deformities required can compromise the arterial inflow to an area. It is best that this is seen during the operation and prior to application of fixation when compromises can be relatively easily made to the surgical objective.

    I have used the Salvation plating and bolts and beams system (Wright Medical) to effect a rigid fixation with compression of the multiple joints with the bolt and added additional fixation with locking plates. This is a comprehensive system designed specifically to address the problems of soft bone such as in Charcot and has anatomic plates specifically for use in medial column arthrodesis.
    The bolts come in different diameters from 5 to 7 mm to allow use in both the first and lesser metatarsals. The idea is to use these fusion bolts to effect axial compression across the 3 joints of the medial column. It has to be used with a secondary fixation devices such as plates or external fixation for maximum benefit. Using these bolts on their own for fixation is not rigid enough a fixation system in diabetic Charcot patients.

    The Salvation plating system showing 4, and 5.5 locking and non locking screws and a range of plates for the medial ray.
    The plating system is also uniquely designed for use in Charcot arthropathy and consists of anatomic plates with locking screw holes. They are contoured specifically for the medial ray and come in two anatomic types to accommodate for anatomic variation. Screws which are available as both locking and non locking have also been designed to obtain optimal purchase in osteopenic bone with a variety of features including an increased minor diameter, osteopenic thread profile distally and 3Di locking head with threads which come in 4 and 5.5 mm diameter. Appropriate diameter screws can be chosen based on the anatomy of the individual patients foot. The plates are designed to be used medially or more commonly dorso-medially.
    The other instrument that is essential in this procedure is the Hintermann distractors which use K-wires in adjacent bones which are threaded on to the distractors through holes in the arms of the instrument.
    I also use synthetic bone morphogenic protein ( IGNITE, Wright Medical) to act as a potent osteo-inducting agent along with bone marrow aspirate. Although I do not routinely use internal or external electrical or ultrasonic bone stimulators I have tended to use them in failed fusions as a ‘Belt and Braces’ option as evidence for the efficacy of such systems is lacking in the context of Charcot surgery.

    The Salvation instrument tray

    In the presence of a tight tendo-Achilles(not uncommon in a fixed plano-valgus collapse) perform a triple-cut percutaneous tendo-Achilles lengthening to correct the equinus as an initial surgical step.This equinus is measured by positioning the heel neutral before dorsiflexing the ankle to uncover the equinus deformity.
    With the patient supine position the leg is elevated for the surgical approach to the achilles tendon. The leg can also be externally rotated at the hip with the patient supine to allow similar access.

    Three percutaneous hemi-sections of the Achilles, two medial and one lateral, followed by controlled and forceful dorsiflexing the ankle, allows the desired correction of the deformity without over-lengthening the tendon.Three percutaneous hemi-sections of the Achilles, two medial and one lateral, followed by controlled and forceful dorsiflexing the ankle, allows the desired correction of the deformity without over lengthening the tendon.
    Care must be taken to avoid injury to the sural nerve laterally and the posterior tibial neurovascular structures medially . However as the incisions in the tendon are made from the midline cutting outwards and stopping as soon as the knife exits the tendon this means that neurovascular injury is rare.

    The first skin incision lies on a line from the medial malleolus(1) along the medial tuberosity of the navicular(2) and extends distally along the medial aspect of the first metatarsal if required reaching the 1st metatarsophalangeal joint.The medial approach to the first ray is a direct inter-nervous one that gives extensile access to the whole of the medial foot from the metatarso-phalangeal joint to the ankle joint.
    Dorsal to the incision lies the deep peroneal nerve and more anteriorly the anterior tibial nerve branches. Posterior to the incision lies the posterior tibial neuro-vascular bundle.
    Tendons that lie in the vicinity include the Tibialis anterior tendon which is anterior to the proximal part of the incision. At the level of the 1st tarsometatarsal joint it crosses medially and plantar-wards to attach to the base of the 1st metatarsal.
    Lateral to this is the Extensor Hallucis Longus tendon which lies lateral and dorsal to the incision. Plantar to the incision is the Tibialis Posterior tendon along with Flexor Digitorum Longus(FDL) tendon which is most at risk in the proximal part of the approach.
    At the level of the navicular, the tibialis posterior tendon attaches to the medial navicular tuberosity with extensions to the medial cuneiform and even to the base of the first metatarsal. The FDL tendon continues plantar top the incision and at the level of the midfoot turns plantar and lateral soon dividing into 4 slips distal to the master knot of Henry.
    The Spring ligament ( inferior calcaneonavicular ligament) lies deep to the tibialis posterior tendon and is almost always stretched, degenerate or torn in patients with this degree of deformity. This is the reason that the talar head sinks into plantar flexion, eventually to reach the floor, when the spring ligament is completely torn or redundant.
    There are often communicating branches of the dorsal veins which cross perpendicular to the axis of the incision which need to be tied off or diathermised.

    The skin is incised along the medial aspect of the foot and the subcutaneous fat divided sharply without de-laminating it from the skin.Occasionally one may encounter subcutaneous nerve branches in the mid part of the incision. Rarely a branch of the saphenous nerve may be encountered. These may have to be sacrificed and diathermised if they are obstructive by their position across the incision.

    The tibialis posterior and flexor digitorum longus tendons are identified and retracted plantar-wards whilst the tibialis anterior is reflected dorsolaterally. The distal part of the tibionavicular component of the medial deltoid ligament is encountered here and can be split to gain access to the medial ray.

    The medial deep fascia and the spring ligament are then divided in line with the skin incision.
    The spring ligament in this case was found to be ruptured completely with the talar head becoming immediately visible(A) on dividing the attenuated ligament. The capsule of the talonavicular joint is opened in the same longitudinal direction to expose the head of the talus.

    A longitudinal extension of the deep incision in the medial aspect reveals the plantarflexed head of the talus and the talonavicular joint.A longitudinal extension of the incision in the medial aspect reveals the plantarflexed head and the talonavicular joint.

    The talo-navicular joint is then identified by division of the capsule and the dimensions of the joint are exposed medial to lateral and dorsal to plantar by subperiosteal dissection.It is important not to release the attachment of the tibialis posterior tendon on to the medial plantar aspect of the navicular.

    Dissect further distally by sharp separation of the capsule to expose the naviculocuneiform joint which is dealt with in a similar manner by elevating the capsule off the joint to expose it in its entirety. This deep dissection is assisted by tension upon the soft tissues with a deeply placed self-retaining retractor. It is important to remember the structures at risk in each of the steps of the procedure.

    Finally the 1st tarsometatarsal joint is exposed in a similar manner by elevating the capsule with sharp subperiosteal dissection. It is of paramount importance not to stray lateral to the base of the 1st MT for fear of injury to the Dorsalis pedis artery which bends plantarwards sharply at the inter-metatarsal region between the bases of the 1st and 2nd metatarsals. Now the exposure of the various joints requiring fusion is complete.

    The talar head is now cleared of all articular cartilage by using curved osteotomes and curettes, whilst the talonavicular joint is distracted open with a Hintermanns retractor.I do not use burrs as they generate heat and also tend to slip off smooth articular cartilage .

    The navicular surface is similarly peppered with a k wire.

    Use a Mitchells periosteal elevator at this stage to completely expose and mobilise the talonavicular joint (TNJ) from medial to lateral and also to perform a plantar release, elevating tight and contracted plantar soft tissues.
    This is an important step in being able to release the plantarflexed talar head so that it can be relocated in the correct axis into the TNJ. This also allows the navicular to be moved medially and plantarward to completely cover the talar head. The connections of the calcaneo-navicular ligament can also be stripped off the lateral plantar aspect of the navicular to allow the medial movement of the navicular to cover the talar head.

    Releasing the lateral aspect of the navicular with the Mitchells elevator.

    The curved osteotome is very useful if used carefully to peel off the articular cartilage from the talar head and is a quick method of clearing articular cartilage.Care must be taken not to lose control of the osteotome if it slips off the talar head as it can penetrate the plantar skin and exit through it!

    The plantar and lateral aspects of the talar head can be difficult to access and therefore the use of skeletal distraction is very useful to gain vision of these areas. I find the Hintermann distractor very useful in achieving this.

    The talar surface then is petalled using an osteotome. I use a ‘hot cross bun’ pattern creating cuts perpendicular to each other to expose subchondral bone

    Similarly the navicular is prepared by excision of the articular cartilage and its articular surface further opened by “petalling” with the osteotome.

    Operation – 2

    Finally a 2 mm K wire is used at slow speed to create multiple holes in the fusion surfaces of the talo-navicular joint.

    The navicular-cuneiform joint is now distracted to allow its preparation by moving the distractor to further pins in the navicular and the cuneiform.

    The naviculo-cuneiformjoint is complex as it often has 2 or even 3 facets with the lateral most facet articulating with the intermediate cuneiform. I do not routinely fuse the naviculo intermediate cuneiform joint but if easily accessible can be done.

    Using osteotomes and curettes the articular cartilage is excised from the navicular and cuneiform articular surfaces.Using osteotomes and curettes the articular cartilage is excised from the navicular articular surface.

    The osteotome is also used to petal the articular surface in the manner described for the TNJ

    The Hintermann distractor is used finally across the 1st taros-meatatarsal joint to gain visualisation of the joint surfaces prior to their preparation, which proceeds along the lines of the more proximal medial joints.

    The articular cartilage is removed using osteotomes and curettes

    Following cartilage removal a K wire is used to make multiple drill holes in the 1st tarsometatarsal joint.

    The joint is now fully prepared following drilling and petalling

    Comparing it to the preoperative picture now gives us the comprehensive correction that has been achieved.

    The joints are carefully placed in their corrected and anatomical position and held with temporary 2 mm K wires. Attention must also be paid to the congruency of each joints reduction which should be optimised by positioning, re-preparation or bone grafting.It is important to place these wires in such a way that they do not obstruct placement of the fusion bolts in an intramedullary position. The position is then assessed by fluoroscopy to ensure full correction of the deformity

    Looking at the sole of the foot and referencing it to the anterior tibial crest and the patella gives a good idea of the extent of the correction of rotational and coronal plane deformities.

    The final joint preparation is of the metatarso-phalangeal joint of the hallux which is opened through a dorsal incision just medial to the Extensor Hallucis tendon.It is important to ensure that the dorsal medial cutaneous nerve is not damaged during this exposure although this lies dorsomedially. Occasionally lateral branches may be encountered and preserved . A 1 inch incision usually will suffice.

    With sharp dissection, the metatarsal head is exposed and the centre point if the articular surface is carefully identified by plantarflexing the MTP joint. A guide wire is then drilled through the centre of the metatarsal head travelling intra-medullary and proximally across the 3 fusion sites to end in the talar bodyIt is extremely important that this position is carefully checked to ensure that the cortices of the various bones will not be breached by the bolt and will also ensure good axial compression perpendicular to the plane of the articular surfaces. This must be checked with fluoroscopy. It is also important that the position be accurately assessed prior to drilling to minimise the damage to the articular surface of the 1st MT head.

    Dedicated cannulated drills are available and the appropriate diameter drill, according to the size of the bolt chosen, is then used to drill the medial ray in line with the axis of the intra-medullary guide wire.The position is checked with fluoroscopy. It may be necessary to remove or reposition the temporary fixation K wires so that they are not damaged or drilled through.

    The appropriate length and diameter fusion bolt is then screwed in. It may be necessary to remove the temporary fixation wires so that they do not obstruct the smooth passage of the bolt through the drill hole.

    The fusion bolt is then screwed in until it lies flush with subchondral bone, deep to the articular cartilage of the first metatarsal head.This will cause severe damage to the proximal phalangeal articular surface if left proud. Compression is confirmed as fluid expresses from the joint surfaces, but should also be checked with fluoroscopy.

    A Salvation plate of appropriate size is then chosen and applied medially or dorsomedially so that it spans all three joints.Too proximal a position will cause the plate to impinge on the medial malleolus or even the tibial lip anteriorly and therefore it is important to check its position in full dorsiflexion of the ankle. This will allow accurate positioning of the plate without any impingement. A proximal dedicated fixation tab(A) is used to hold the proximal position of the plate. The plate has 2 oblong dynamic compression holes to effect sequential compression of the joints if required. The position is checked again on fluoroscopy.

    A distal temporary fixation tab (shown being inserted here)can be used to stabilise the plate until the first joint is ready to be dynamically compressed.

    The talar end of the Salvation plate is first fixed using locking screws. A threaded drill guide ensures accurate drilling which is key as the screw holes are not poly-axialUsing a depth gauge, screw length is measured. It is important to not use too long a screw for fear of broaching the anterior subtalar joint or the sinus tarsi.

    The first dynamic compression screw is inserted to the proximal oblong hole of the Wright Salvation plate in an eccentric fashion after drilling and measuring screw length.It is important to remove the distal temporary tab when the screw is nearly ready to start to compress the talonavicular joint. The screws are colour coded to avoid confusion

    Two locking screws are inserted into the navicular part of the plate into the navicular body, followed by the non-locking compression screw inserted to compress the naviculo-cuneiform joint.Again it is important to remove the distal temporary tab prior to compression. The position is checked on fluoroscopy.

    Lastly the metatarsal locking screws are inserted into the salvation plate. Lastly the metatarsal locking screws are inserted. I often use compression of this joint with sharp reduction clamps prior to insertion of the locking screws as this part of the plate does not have a dedicated compression screw hole.
    Bone graft and IGNITE are now used to augment fusion and fill any voids.

    The final position is clinically assessed as described before. Note the recreation of the arch following the correction

    The wound is carefully closed in 2 layers with interrupted sutures. I use 2-0 Vicryl for the subcutaneous/fascial suture.After the final position is checked with fluoroscopy, the wound is thoroughly irrigated with Betadine solution. The wound is then carefully closed in 2 layers with interrupted sutures. I use 2-0 Vicryl for the subcutaneous/fascial suture.

    Operation – 3

    Completion of subcutaneous/fascial layer suture

    I use interrupted 3-0 absorbable undyed vicryl in interrupted mattress sutures for skin.I use interrupted 3-0 absorbable undyed vicryl in interrupted mattress sutures for skin.
    The stab incisions for the Tendoachilles lengthening are closed with Steristrips.

    A below knee Plaster of Paris back/U slab is applied after an ankle local anaesthetic block with 30 ml of 0.5 % Chirocaine has been given.

    Postoperative radiograph AP of the operated foot at 6 weeks. Note good coverage of the talar head with the navicular in the fusion construct and correction of the talo-first metatarsal angle. The abduction deformity has been fully corrected.

    Oblique radiograph of foot at 6 weeks. Note good progression of fusion at 6 weeks

    Lateral radiograph at 6 weeks.
    The calcaneal pitch has been restored by elevating the anterior process of the calcaneus along with dorsiflexion of the axis of the talus and the Meary angle Talo-first metatarsal angle corrected to neutral.

    Post Operative

    The postoperative protocol for fusion of the Charcot midfoot remains a challenging aspect of the treatment. It is my practice that the patient is kept non weight bearing for at least 10 weeks and sometimes longer. This can be very difficult for a patient for very practical reasons but its importance has to be emphasised.Other issues also arise as a consequence of non-weight bearing, in particular a lack of mobility makes glycemic control very difficult.
    I review the patient at 1 week to assess the wound and then every week thereafter to change the plaster as there is a significant risk of plaster induced ulceration due to the peripheral neuropathy.
    Patients are often converted to a Beagle Bohler Walker(Beagle Orthopaedics Ltd) at 6 weeks to help them ambulate which helps with glycemic control. This is a significant advantage in being able to keep the patient’s morale up whilst having its biomechanical advantages as well as the psychological gains for the patient who can gain a degree of independence at least whilst at home.
    A radiograph AP, Lateral and oblique of the foot is procured at 6 weeks, 3 months and eventually if required at 6 months. The patient is also measured for a semi-rigid diabetes friendly orthosis at 6 weeks so that this can be used at 3 months when the patient is finally ready to mobilise weight bearing.

    Recommended Reading

    The results of fusion of the midfoot in Charcot disease is variable with a high risk of complications including metalwork failure, non union, wound breakdown, infection and amputation. Meticulous preparation of the joint, use of osteoinductive adjuncts, full correction of deformity, and the use of robust and Charcot specific implants are the main tenets of such fixation. As mentioned before a multidisciplinary approach is indispensable for the success of such formidable procedures. There are no long term Level 1 studies that can rely on a particular system of fixation to offer predictably good results due to the variety of implants that are required for this challenging condition. Confounding variables make the provision of such results almost impossible. An “A la Carte” approach is often required with a wide variety of operative techniques, implants and strategies being available for use in different clinical settings.
    Some results of fixation bolts and complex fixation with a variety of implants are given below:
    Journal of Foot and Ankle Surgery 2013 Mar-Apr;52(2):235-8. doi: 10.1053/j.jfas.2012.12.003. Epub 2013 Jan 11. Early results with the use of midfoot bolts in Charcot Arthropathy. Cullen BD et al.
    Orthopaedic Proceedings Feb 21st 2018 Online publication: Corrective fusion for Charcot Neuroarthropathy: The Kings Experience
    Foot Ankle Int. 2019 Jan;40(1):18-23. doi: 10.1177/1071100718799966. Epub 2018 Oct 4. Clinical Outcomes and Complications of Midfoot Charcot Reconstruction With Intramedullary Beaming. Ford SE1, Cohen BE2, Davis WH2, Jones CP2.

    Reference

    • orthoracle.com

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