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Tibialis Anterior Reconstruction (Extensor Hallucis Longus transfer)

    Overview

    Learn the Tibialis Anterior Reconstruction (Extensor Hallucis Longus transfer) surgical technique with step by step instructions on OrthOracle. Our e-learning platform contains high resolution images and a certified CME of the Tibialis Anterior Reconstruction (Extensor Hallucis Longus transfer) surgical procedure.
    The Tibialis Anterior is not commonly effected by tendon pathology.
    Degenerative change is treated like any other tendon with a non-operative program including physiotherapy and activity modifications initially.
    The tendon transfer detailed here is of use after a radical debridement of a degenerate tendon or in reconstructing a chronic rupture .

    Indications


    The Tibialis Anterior is not a tendon which is commonly effected either by tendinosis or rupture. The first line management of the tendinotic tendon is of course with activity modification and direct and indirect physiotherapy interventions to the tendon. A period of cast or post-operative boot immobilisation is also of use conservatively.
    Investigation is in my practice primarily using MRI imaging as a “route map” to define the areas that require surgical intervention though if degenerate change may be very limited or the pathology just involving the paratenon I opt for ultrasound. This leaves open the option of
    In those cases of tendinosis which fail to respond to conservative measures a debridement and repair of the tendon is the normal first stage of operative management. This is managed very like any other hindfoot tendon with most cases being suitable to light partial weight-bear in a post-op boot after 2 weeks of non-weight bearing in a cast.
    The technique detailed, transferring Extensor Hallucis Longus across a defect in Tibialis anterio, can either be used after radical debridement of the tendon (as in the case shown after failed primary tendon procedure) or to salvage a rupture where the tendon ends are un-opposable.
    Alternatives are to transfer Extensor Digitorum Longus or use free autograft from Hamstrings, Achilles, Plantaris or Allograft.
    In the Elderly or low demand management with an AFO or foot drop splint may be appropriate.

    Setup

    Operation carried out with the patient supine
    The incision used most sensibly is directly onto the tendon or just lateral to it.
    The addition of rolled up sterile towels behind the calf helps with positioning.
    Thigh tourniquet to be used and flowtron dynamic calf compression on the non-operated limb
    Prophylactic antibiotics and LMWHeparin peri-operatively & post-operatively
    Bipolar diathermy
    Laminar flow theatre if available.

    Operation

    The skin incision is directly over the Tibialis anterior , or just lateral to it.
    The skin is thin and should not be undermined.
    The length of incision required for a transfer runs from proximal to the ankle to the insertion of the Tibialis anterior distally.

    The skin is mobilised carefully with fine dissection keeping its fat layer attached and avoiding undermining. The extensor retinaculum is a fine layer to be divided before opening the Tibialis Anterior sheath (seen here completed).
    The sheath should be carefully sharp dissected off the tendon and left as a separate layer for reconstruction at the end of the operation.
    Proximal to the ankle the neuro-vascular bundle sits between the Tibialis anterior and the Extensor Halucis longus(EHL). At the Ankle joint and distal the bundle moves laterally to sit between the EHL and Extensor Digitorum Longus (EDL).

    The Tibialis Anterior can now be inspected for degenerative change and tears . Here there is a very clear intra-tendinous split in the area of degenerative change. The tendon itself is intact.

    The Deep Peroneal nerve sits lateral to the tendon in the fat layer and should be looked for and avoided. If injured it produces a patch of variable numbness.
    It sits superficial to the Extensor retinaculum which needs to be divided to access the tendon.

    Just lateral to the Tibialis anterior is the Extensor Hallucis Longus tendon (identified here with the scissor tips). Beneath and coursing laterally lies the anterior Tibial neuro-vascular bundle.
    The Tibialis anterior is traced down to its insertion in the Navicular and inspected.

    The EHL tendon is now exposed distally at the level of the MTP joint through a dorsal incision.

    A good length of tendon is required for the transfer and EHL is sectioned at the level of the joint.

    There are various ways to prepare the distal EHL for reconstruction with the Extensor Hallucis Brevis.

    The distal end of the Extensor Hallucis Brevis is sectioned at the level of the MTP joint and routed into the EHLs’ end. It is sewn into it with a number of non-absorbable braided sutures.

    The contra-lateral foot has also been draped and prepared to allow accurate re-tensioning of both the distal EHL re-attachment ( as well as subsequently the proximal Tibialis Anterior reconstruction).

    The EHL is delivered proximally into the wound using controlled traction with a McDonalds and tendon hook.

    The EHL delivered proximally.

    The EHL muscle belly may need to be released or slightly de-bulked to allow the tendon adequate mobility for transfer.

    Given the revision nature of this case with a Tibialis anterior tendon that has failed to improve the treatment of the degenerate portion of the tendon is radical. The healthy ends of the Tibialis anterior have been marked both ends with sutures and the problematic area is now being excised.

    The proximal end of Tibialis anterior is controlled with the suture and an incision made of adequate dimensions to allow the EHL to be routed through it , without undue tension.

    The EHL delivered through the Tibialis anterior. It is important that the muscle is not constricted at all .This may require excising some muscle belly.

    Distally the same manouvre is performed , allowing a good anchor point in the distal Tibialis Anterior tendon stump.

    Once the EHL has been routed through the Tibialis anterior distally there is sufficient length to allow it to be reversed and taken proximally again. This provides additional tendon material for the reconstruction.

    In this case there is sufficient length of tendon to allow the EHL to be routed all the way back to the proximal end of the Tibialis anterior , producing a double thickness composite tendon. Attention should be paid at this stage , before definitively anchoring the tendon transfer , to ensure that the composite tendon is under appropriate tension. The opposite ankle should be referred to to get this correct.
    More relevant in cases of longstanding rupture an assessment should be made of the mobility of the Achilles tendon. It may become tight and require formal release if this is the case.

    The composite tendon after suturing. A combination of heavy sutures may be used. Braided absorbable and non-absorbable are both appropriate.

    After repair of the sheath over the tendon. Care should be taken to de-bulk any prominent areas of the transfer. The sheath is closed using an absorbable suture.
    Fat and skin are closed with Vicryl sutures in layers. A Sub-cuticular skin closure is used.

    It is not easy to see on the T1 image but there is discontinuity of the Tibialis anterior tendon at the level of the ankle joint.

    The Tibialis anterior rupture (1) is more easily seen on the T2 imaging , again at the level of the ankle joint.

    Post Operative

    5-6 weeks in below knee cast post-operatively and non-weight-bear
    Dressing changes at 1 & 2 weeks
    Long Air-cast boot to follow after 5-6 weeks
    Of greatest 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 excercises and non-weight bear strengthening regime from when out of cast
    Avoid pushing Ankle range early as this risks over-lengthening/stretching the newly repaired tendon
    Increase weight bearing as comfortable in boot , likely able to come off crutches by 8 weeks post op
    Commence weight-bearing rehab (strength & balance) from when able to full weight bear.
    Take functional rehabilitation with bike , cross-trainer and treadmill very gradually.

    Recommended Reading

    Surgical repair of Acute and Chronic Tibialis anterior Tendon ruptures.
    J Bone Joint Surg.2009. 91-A; 325-332
    V.J.Sammarco , G.J.Sammarco ,C.Henning , S.Chaim.
    19 ruptures reported at various stages post event with a mixture of direct repair and various autogenous grafts.
    Ankle dorsiflexion 5/5 MRC in 15 , 4/5 MRC in 3 & 3/5 in one patient
    Systematic review of Tibialis Anterior tendon rupture treatments and outcomes
    Am J Orthop.2015; 44(4):E94-E99
    Chrisman-Skieller C, Merz M, Tansey JP
    An excellent review article .Available full text on-line at :
    http://www.mdedge.com/amjorthopedics/article/98425/foot-ankle/systematic-review-tibialis-anterior-tendon-rupture

    Reference

    • orthoracle.com

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