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Achilles tendon lengthening- open

    Overview

    Learn the Achilles tendon lengthening: open surgical technique with step by step instructions on OrthOracle. Our e-learning platform contains high resolution images and a certified CME of the Achilles tendon lengthening: open surgical procedure.

    An acquired equinus contracture of the ankle has a number of more common causes. Despite early bracing and functional rehabilitation it can occur after traumatic or ischemic brain injury, spinal cord injury, ischaemic muscle contracture or as part of a more generalised neurological condition.
    Recovery specifically following traumatic or ischaemic brain and spinal cord injury is variable. In those whose function is sufficient enough to allow standing or walking, the equinus contracture can become a limiting factor in their rehabilitation. Whilst equinus deformities can be caused by a variety of muscle contractures and joint contractures, normally the achilles-gastrocnemius-soleus complex is the first to develop the fixed deformity. Thus in those cases that present within 2-3 years of a contracture developing an isolated achilles release is usually sufficient to correct the deformity.
    The restriction caused by a contracted Achilles tendon will usually become apparent within 2 years of the neurological insult, and as such, this patient population more often have not yet developed significant contracture of their long flexors and joint capsules, when compared to the more chronic neurological or pediatric equinus contractures, or the ischemic muscle contracture group.
    Patients with ischemic or traumatic brain injury should be managed in a multi-disciplinary environment, and will require input from Neurologists and Neuro-rehabilitation therapists, Occupational therapists and of course the most important part of any team, the Orthopaedic surgeons.



    Indications

    INDICATIONS
    The indications for an open achilles tendon lengthening include:
    -Severe, fixed and isolated equinus that has not responded to appropriate non-operative management.
    -Achilles tendon contracture in association with contracture of other long flexors of the foot and ankle.
    -Ischaemic forefoot plantar pressure ulceration: the procedure can be helpful in offloading the forefoot and aiding in ulcer healing. In diabetic patients the ankle equinus maybe subtle, in which case a less invasive Hoke lengthening may be more appropriate in the presence of plantar forefoot ulceration.
    In milder or relatively recent contractures a less invasive Hoke triple-cut of the tendon may be more appropriate, and if the contracture is isolated to the Gastrocnemius, a gastrocnemius release should be considered.
    HISTORY
    Many patients will have undergone treatment with neurologists, physiotherapy and occupational therapists, in a neuro-rehabilitation unit. In order to benefit from a release of an equinus ankle contracture, patients will have made functional gains following their initial insult, and have reached a stage where the equinus contracture has begun to restrict further progression. This restriction maybe in the use of a standing frame or of balance during the stance phase of gait. It is often helpful to gain information from one of the patients’ neuro-rehabilitation team, in order to gain a more complete picture of where the patient is in their cycle of recovery, what their specific restrictions are, how it is perceived their equinus contracture limits their ability to stand and walk, and what further recovery is expected. A history of previous treatments should be taken, including serial casting and Botulinum toxin injections. It is helpful to know the location and extent of the cerebral injury and the level and extent of spinal cord injury, which limbs have been effected and if the patient has any co-morbidities
    EXAMINATION
    Examination should be performed ideally, with the patient lying, standing and walking. Any fixed deformity in pelvis, hips, knees should be documented, as should flexibility of these joints. Muscle power in hips, knees ankle and core should be assessed. Equinus contracture in the ankle is examined, both with the knee flexed and extended (Silverskiold test, see below) in order to determine whether the equinus is related to an achilles or is an isolated gastrocnemius contracture. The degree of equinus deformity should be documented carefully for both.
    Hindfoot mobility and correctability should be assessed. An uncorrected hindfoot varus may be related to a tibialis posterior contracture and fixed flexion deformities of the toes may indicate contracture of the long flexors. The midfoot should be assessed in relation to the ankle and hindfoot, to gain an impression as to whether there is an associated midfoot deformity (plantaris). Muscle power in each muscle group, should be tested and documented, which can help with surgical planning especially when tendon transfers may be considered. Finally the tibial and dorsalis pedis pulses should be palpated to ensure that there is adequate vascularity.
    IMAGING
    Radiographs of the foot and ankle should be routinely performed, these can help define if the location of the deformity is in the ankle, midfoot or both, and may identify any associated degenerative change within the foot or ankle that may compromise any soft tissue correction of the equinus deformity.
    ALTERNATIVE OPERATIVE TREATMENT
    In patients with a mild fixed equinus(<15 degrees) who fail non-operative management a “Hoke” triple cut lengthening will usually suffice. Here using posteriorly based stab incisions, whereby the distal and proximal cuts are through the medial 50% of the tendon and the middle cut through the lateral 50% of the tendon, firm controlled dorsiflexion of the Achilles produces a palpable and instantaneous “giving” of the tight tendon, which stretches sufficiently to allow correction.
    In larger deformities, or where there is contracture of the posterior capsule and long flexors, this will not allow adequate correction, and the triple cut will have compromised a formal open lengthening.
    In patients who have a positive Silverskiold test, where ankle equinus is corrected with the knee flexed but fixed with the knee extended, one should consider an isolated release of the gastrocnemius complex either with a Strayer type release or a medial head of gastrocnemius release.
    NON-OPERATIVE MANAGEMENT
    Surgery should not be considered until non-operative measures are attempted. The adage “prevention is better than cure” holds true with acquired equinus deformities of the ankle, and in patients with intra-cerebral bleeds, cerebral contusion or spinal injuries, passive exercises to stretch the achilles and treatment with an Ankle-Foot-Orthosis(AFO) should be instigated early.
    In patients with established equinus contracture, again passive physiotherapy stretches and splinting can be helpful. Serial casting after stretching and manipulation can be helpful, this can be performed in association with botox injections into the gastrocnemius or soleus and gastrocnemius, depending on whether the silverskiold test indicates an isolated gastrocnemius contracture.
    CONTRAINDICATIONS:
    Whilst achilles release can be very effective in correcting ankle equinus, a full assessment of joint flexibility and proximal muscle power, control and spasticity should undertaken before deciding to proceed. Patients who have significant proximal weakness, spasticity or restricted knee and hip movement can be at risk of decompensating following isolated achilles release. An example of this is a patient suffering from cerebral palsy, with a crouch gait, weak and poorly controlled gluteals and quadriceps, fixed flexion deformities of hips or knees. These patients rely on their relatively powerful achilles(gastroc-soleus) to stand and initiate gait. In these patients isolated release of the Achilles can have a dramatically detrimental effect on their ability to stand and walk.
    Other contraindications to isolated achilles tendon lengthening include active infection, cellulitis, peripheral vascular disease, and severe ankle arthritis (patients with ankle arthritis may be better served with an ankle arthrodesis in association with achilles release).
    COMPLICATIONS
    Complications of open achilles lengthening include triceps-surae weakness, rupture, recurrent equinus contracture, residual deformity, anterior ankle impingement, infection, wound breakdown, thrombo-embolic disease and sural nerve injury.

    Setup

    Achilles tendon lengthening is performed under general or regional anaesthesia.
    My preference is to position the patient prone, using a Montreal type mattress, which allows us access to the posterior ankle and allows access to both ankles in the case of bilateral equinus contracture.
    A thigh tourniquet is applied, skin is prepared with an alcoholic preparation to above the knee, prior to surgery a Silverskiold test is performed to confirm the equinus contracture is of the gastrocnemius-soleus and not an isolated gastrocnemius contracture, demonstrated by the observation that the contracture persists when the knee is bent, (whilst the contracture is overcome by flexion of the knee, in an isolated gastrocnemius contracture).

    Operation – 1

    A moderate and isolated equinus deformity shown during weight-bearing.
    Its extent is beyond what a triple cut to the tendon will correct.

    Clinical examination of equinus is made with the knee both extended and flexed.
    This photograph demonstrates an equinus contracture of the ankle, notice the knee is held straight.
    This examination finding would be compatible with both an isolated gastrocnemius contracture or a gastrocnemius-soleus contracture.


    In this photograph, the knee is seen to be bent, which relaxes the gastrocnemius muscle, as it originates from the femur.
    The persistent equinus deformity indicates that the achilles/soleus are contracted, hence an achilles lengthening is appropriate and not a gastrocnemius lengthening.

    Mark a longitudinal and postero-medial incision midway between the achilles tendon and the posterior border of the tibia.
    The incision allows good access to the achilles tendon, the deep long flexors and the posterior ankle. The wound is not directly or over the relatively avascular achilles tendon and its repair. The incision reduces skin tension along the wound once the ankle is bought to plantigrade when compared to a direct posterior approach. The incision should extend from the musculotendinous border of the Gastrocnemius-soleus complex and the superior border of the calcaneum.

    Using a size 10 scalpel blade, a longitudinal incision is performed through the pre-planned marker, the incision should be full thickness down to the paratenon.
    Excessive undermining of the soft tissue flap should be avoided, in order to prevent devascularization of the skin flap. The incision through the deep fat should be inclined posteriorly, towards the achilles tendon.

    Once the paratenon is identified, the deep fascia should be gently elevated off it.
    Having it clearly visualised assists in the closure of the paratenon layer over the achilles repair.

    A pair of McIndoes scissors is passed deep to the paratenon, in the plane between it and the tendon.The tendon is protected by the McIndoes scissors passed deep to the paratenon which is divided longitudinally onto the scissors using a scalpel.

    If the plantaris is present, it can usually be identified on the medial aspect of the achilles tendon and the plane between it and the achilles tendon is developed. If the plantaris is tight it can be released along with the achilles, but if after achilles tendon lengthening, the ankle comes up to 90⁰ it can used as an augment to the repair.
    The plantaris has been dissected from the medial aspect of the Achilles tendon here and appears comparatively lax.

    The sural nerve should be identified and protected, before the tendon is lengthened. It is intimately related to the achilles tendon, and crosses its lateral border at 8-10 cm above the calcaneal tuberosity.
    This is where it is at most risk of iatrogenic injury.

    Blackmon JA. J Foot Ankle Surg. 2013 Feb;52.
    Locating the sural nerve during Achilles tendon repair: a cadaveric study with clinical applications.

    The Sural nerve lies within the deep fascia, immediately adjacent to the paratenon.
    The sural nerve here can be seen to run lateral to the achilles tendon and is identified with a yellow sloop. It must be handled minimally.

    The initial tendon cut is a longitudinal incision through the achilles tendon.
    It is helpful to hold the ankle in dorsiflexion to ensure that there is maximum tension within the achilles tendon in order to aid the progression of the incision.
    A forceps(as shown) or McDonalds is placed under the deep surface of the tendon and is moved distally in tandem with the scalpel, providing a degree of control and tactile feed-back. Incisions should be performed slowly to avoid skiving medially or laterally thus preventing premature completion of the ‘Z’ cut.

    Once the longitudinal incision is performed the tenotomy is opened using Mcindoe scissors.
    This step ensures that the tendon has been completely divided and any remaining traversing fibres are divided.

    Once the longitudinal incision has been completed its length is checked, the standard being 10cm.The longitudinal incision is performed over a longer length than might be expected, this is necessary to achieve adequate side to side apposition of the tendon once the foot has been bought to plantigrade. if a shorter longitudinal division is made there is a risk that there will be very little apposition of the side to side repair or indeed a gap between the achilles tendon ends.

    The distal limb of the tenotomy is now completed through the lateral half of the tendon, just above the superior border of the calcaneum.
    I elect to perform the distal cut laterally in order to reduce the risk of injury to the sural nerve as the sural nerve crosses 8-10m above this point.
    The medial transverse incision is performed about 10cm proximal to the superior border of the calcaneum, and below the musculotendinous junction.

    The proximal transverse cut(A) to the tendon is made medially and just distal to the the musculo-tendinous junction.
    The plantaris tendon can be seen intact, and can be released if it is preventing correction.

    Maintaining dorsiflexion of the ankle whilst completing the Z-cut.With a small amount of encouragement the proximal end of the Z-lengthening is seen to start distracting (A).

    The ankle is firmly dorsiflexed to distract the tenotomy, and break down any minor capsular contracture.The correction is then assessed and the ankle should be able to dorsiflex beyond plantigrade. Shown here the ankle is dorsiflexed 10⁰ beyond plantigrade.

    Hindfoot alignment and toe position should be assessed following achilles release as well as the adequacy of the ankle equinus correction, prior to achilles tendon being repaired.
    If inadequate dorsiflexion is achieved, the posterior ankle is approached through the bed of deep investing fascia, located directly beneath the achilles. This is divided exposing the FHL tendon and more medially the posterior tibial nerve and FDL tendon. The FHL is retracted medially to expose the posterior ankle capsular which can then be divided.

    If there is residual fixed flexion of the toes sequential Z lengthening of the FHL and FDL tendons are then performed and it is essential that the tibial nerve is identified and protected before releasing the tendons.
    In the case of residual hindfoot varus a tibialis posterior tendon lengthening is performed.

    Once adequate dorsiflexion is achieved the achilles tendon is repaired using a side to side suture technique using an absorbable 1 Vicryl as an interrupted suture.
    Three to four sutures are passed firstly over the posterior aspect of the tendon and subsequently between the two deep aspects of the tendon, we tend to use six to eight stitches.

    The achilles should be repaired with the foot held in 5-10 degrees of dorsiflexion, the aim is to have a moderate degree of tension within the tendon in this position.
    Once reduced the Achilles tendon is repaired using a side to side technique, it is important to gauge the correct tension in the tendon.

    The robustness of the repair should be tested as well as the tension within the repair.The overlap of the repair can be seen between four and 5 cms here, which allows an adequate side to side repair, the overlap of the tendon ends maybe less than this in more severe equinus deformities.

    The paratenon is then identified and closed with an absorbable 2/0 vicryl suture in an interrupted fashion over the tendon and avoiding the sural nerve.
    The lateral limb of the Paratenon is identify and transfixed with a non absorbable suture.

    The deep fascia is closed over the repaired paratenon, again with interrupted absorbable sutures.the deep fascia is closed over the paratenon.

    A second more superficial fascial suture reduces the incidence of tethering between the skin and tendon.Closure of the superficial fascia with a non-absorbable suture.

    Operation – 2

    Complete closure of the superficial fascia.Following the repair of the paratenon and deep and superficial fascia layers the wound can be seen to be well opposed with minimal tension with the ankle held in plantigrade.

    Skin closure with a non-absorbable, interrupted mattress suture to avoid tension on the wound edges.Non-absorbable Interrupted vertical mattress suture.

    Finally a Silverskiold test is performed on table to ensure that adequate dorsiflexion is achieved.

    Local anaesthetic is infiltrated subcutaneously using a long acting local anaesthetic.

    Dry dressings are applied to the wound, followed by protective layer of wool.the wounds are dressed in dry dressing.

    A backslab is applied with the ankle held in plantigrade.If there is residual flexion in the toes then a shelf should be incorporated into the plaster to hold the toe dorsiflexion.

    The foot is held corrected until the plaster is set prior to transferring the patient.A backslab is then applied below knee with adequate padding underneath ensuring that the foot is held plantigrade until the plaster is fully set

    Post Operative

    4 weeks in below knee cast post-operatively. The plaster should be applied with the ankle in plantigrade whilst in the operating room, the sound side to side repair will tolerate the slight tension that the achilles should be under. The ankle should not be placed in equinus, as this tends to lead to incomplete correction, excessive dorsiflexion will lead to lengthening of the achilles and unnecessary weakness.
    Patients can be allowed to fully weight-bear from 2 weeks.
    Dressing changes at 1 & 2 weeks
    Long pneumatic boot or a custom Ankle-Foot-Orthosis(AFO) to follow after 4 weeks, until 12 weeks. Those with neurological weakness or spasicity, are likely to continue to wear an AFO.
    Of upmost importance through-out the post-operative period is that the wound is looked after. Wound infection and small areas of breakdown occur easily in a freshly healed wound that is allowed to rub on socks/shoe-wear after a patient is out of cast.
    Any exudate from the wound which is allowed prolonged contact with the wound will further exacerbate any skin breakdown . Dressing changes may therefore need to be frequent if such a complication ensues.
    Once out of cast I routinely advise another month of daytime dressings when in shoes and also nocturnal dressings whilst any of the wound remains unhealed
    Showering & bathing is allowed from when out of cast
    Commence range of motion exercises and non-weight bear strengthening regime from when out of cast
    Increase weight bearing as comfortable in boot, likely able to come off crutches by 8 weeks post op

    Recommended Reading

    1. JBJS Br. 1988 May;70(3):472-5.
    Graham HK, Fixsen JA.
    Lengthening of the calcaneal tendo Achilles in spastic diplegia by the White slide technique. A long term review.
    This study followed 35 patients with spastic hemiplegia for 14-20 years and concluded that it was a simple technique with low complications, recurrence rates and satisfactory outcomes over the long term.

    2. FAI 2005 Dec;26(12):1017-20
    Lee WC1, Ko HS.
    Achilles tendon lengthening by triple resection in adult.
    25 ankles with spastic paralysis, percutaneous triple cut achilles tenotomy(hoke) followed up for 1 year. They concluded that there was a risk of achilles rupture in more severely equinus corrections (>30deg), there was an 8% incidence of residual deformity The study suggests that the Hoke tenotomy may have limitations when used for more severe equinus deformities.
    3. FAI 2008 Mar:29(3):325-8.
    Redfern JC1, Thordarson DB.
    Achilles tendon lengthening/posterior tibial tenotomy with immediate weightbearing for patients with significant comorbidities.
    This study followed 13 ankles in 10 patients who underwent achilles lengthening, with tibialis posterior tenotomy, all of the patients had significant comorbidities, the equinus was corrected from a mean of 26 degrees to 1 degree and an improvement in ambulatory status. The study shows that achilles release is effective in correcting ankle equinus, early weight bearing is well tolerated, and was effective in improving ambulatory status.
    4. FAI 2013 Sep:34(9):1233-7
    Sung KH1, Chung CY, Lee KM, Lee SY, Park MS.
    Anterior ankle impingement after tendo achilles lengthening for long standing equinus deformity in residual poliomyelitis
    27 patients with longstanding equinus deformity of the ankle underwent achilles tendon lengthening, there was a 88% incidence of radiographic anterior ankle impingement, most of which were symptomatic, the impingement was significantly worse in those with more severe equinus deformities. The study suggests that further surgery may be required to address ankle impingement following achilles release for long standing equinus, certain in the poliomyelitis group.
    5. JBJS 2013 Aug21;95(16): 1489-56 95
    Firth GB1, McMullan M, Chin T, Ma F, Selber P, Eizenberg N, Wolfe R, Graham HK.
    Lengthening of the gastrocnemius-soleus complex: an anatomical and biomechanical study in human cadavers.
    A cadaveric study comparing 6 different triceps-surae and achilles lengthening procedures, they found that releasing the Triceps surae at deifferent levels bestowed different mechanical and anatomical characteristics whilst a number of the more proximal procedures such as the Baker, Strayer and Vulpius were more stable releases, the z lengthening of the achilles provided a more powerful correction of equinus.
    6. . J Foot Ankle Surg. 2013 Feb;52(1):42-4
    Blackmon JA, Atsas S Clarkson MJ, Fox JN, Daney BT,Dodson SC, Lambert HW
    Locating the sural nerve during Achilles tendon repair: a cadaveric study with clinical applications.
    This was an anatomical study of 107 cadaveric leg dissections, aiming to estimate the intersection point where the sural nerve crosses the lateral border of the Achilles tendon, and is at high risk from iatrogenic injury. In most cases, the sural nerve crossed the lateral border of the Achilles tendon 8 to 10 cm proximal to the superior border of the calcaneal tuberosity. The relevance of this study is that the location of the sural nerve can, in most cases be reliably predicted, and in open achilles lengthening is directly within the surgical field and therefore can be identified and protected.

    Reference

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