///

Crossover second toe deformity- Extensor Digitorum Brevis transfer

    Overview

    Learn the Crossover second toe deformity: Extensor Digitorum Brevis transfer surgical technique with step by step instructions on OrthOracle. Our e-learning platform contains high resolution images and a certified CME of the Crossover second toe deformity: Extensor Digitorum Brevis transfer surgical procedure.
    A crossover deformity usually effects the second metatarso-phalangeal(MTP) joint though the third or fourth joints can be far more rarely effected.
    It is most often a multi-planar deformity and can encompass both varus and hyperextension at the MTP joint as well varying degrees of flexion of the PIP toe joint.
    Pain will occur due to dorsal and medial second toe impingement as well as from the web space and plantar aspect of the second metatarsal head and the effected MTP joint. The webspace is commonly afflicted by a neuroma/bursa complex, the metatarsal head by plantar plate tear and mechanical overload and the joint by florid synovitis.
    If caught early some attempt at corrective taping after steroid infiltration may be useful but most symptomatic cases require operative correction.

    Indications

    INDICATIONS
    A Cross-over toe deformity (most usually effecting 2nd toe but 3rd or 4th can be effected)
    SYMPTOMS & EXAMINATION.
    A crossover deformity usually effects the second metatarso-phalangeal(MTP) joint though the third or fourth joints can be far more rarely effected.
    It is most often a multi-planar deformity and can encompass both varus and hyperextension at the MTP joint (progressing as far as joint dislocation) as well varying degrees of flexion at the PIP toe joint. Any valgus deformity of the Hallux may accentuate the second toes position once it deviates into varus and should be looked for in every case. A not uncommon association is with a hallux interphalangeus (such as in the case illustrated) though if the hallux position does not compromise the 2nd toe correction it can be left untreated.
    Pain will occur due to dorsal and medial second toe impingement as well as from the web space and plantar aspect of the second metatarsal head and also the joint. The webspace may be afflicted by a neuroma/bursa complex , the Metatarsal head by plantar plate tear and mechanical overload and the joint by florid synovitis. All areas should be appropriately examined.
    In terms of its aetiology the deformity arises progressively and is due to imbalance of tendon function arising usually from 2nd MTP joint capsular compromise. Capsular laxity or tears can be secondary to synovitis of the joint , plantar plate insufficiency or the chronic inflammatory change associated with a Mortons’ neuroma. Once it presents the deformity tends to progress. A neuroma will be identified pre-operatively by ultrasound and if present needs surgical removal. The greatest of care must be excercised if surgical approaches are required in the adjacent web spaces of a toe due to the risk of acute vascular compromise. Consideration can be given to staging surgery.
    A grading system has been published by Haddad & Myerson et al (see results) which classifies the deformity into 4 progressive stages with starting with synovitis and mild MTP varus and ending with frank MTP dislocation. This does reflect the way the deformity tends to progress but does not take account of the deformity that can also occur at the PIP joint. In an early case a simple capsular repair and extensor lengthening may suffice but as the severity and multi-planar nature progresses so does the complexity of surgery required.
    INVESTIGATION.
    Plain X-Ray: Is indicated if their is any indication of degenerative change at the MTP joint and to document the degree of second toe and associated hallux deformity.
    Ultrasound : This is the one investigation that identifies most of the pathologies that require treating.
    NON-OPERATIVE ALTERNATIVES.
    In reality this is one forefoot deformity that due to its progressive, multi-planar nature and the inflammation associated is rarely well managed with accommodative shoe-wear .
    Steroid and local anaesthetic infiltration under ultrasound guidance followed by corrective taping of the toe may help temporise symptoms in early presenting cases but usually little more than this.
    OPERATIVE ALTERNATIVES.
    –Capsular repair and extensor tendon lengthening : This is the initial stage in most operative treatment but may be performed in isolation.
    -Flexor to extensor transfer: Debate exists about its role ( whether to use in milder or conversely more severe cases).
    –Weils osteotomy & Arthrex scorpion capsular repair : This is the subject of a forthcoming technique
    CONTRAINDICATIONS.
    Factors that compromise would healing such as poor vascularity , immunosuppressive medications and conditions and smoking need to be optimised pre-operatively.

    Setup

    Ga or Regional anaesthesia
    Popliteal nerve block for post-operative pain relief
    Thigh or ankle tourniquet
    Small wire driver
    Small artery clips /tendon passing forceps
    Double-ended 1.6 K wires

    Operation

    The deformity involves varying degrees of MTP joint extension and varus, PIP joint flexion/fixed flexion and 2/3 web-space swelling. Commonly ( but not invariably) there is a neuroma in the 2/3 webspace and tear in the plantar plate / 2nd MTP capsule.
    Consideration should be given to the hallux also & assessment made of any associated Hallux valgus or (as in this case ) Hallux interphalangeus. It is worth considering correcting an intercurrent and impinging Hallux interphalangeus or second toe correction may still result in contact between the two.
    In this case it looks as though a correction of the second toe, so it sits next to the third will not additionally require an Akin osteotomy.

    A long and dorsal incision between the second & third metatarsals is made to gain enough proximal length from the Extensor Digitorum Brevis tendon, a key part of the correction.The effected web space also needs to be accessed.

    Progression of the dissection. Through-out the procedure a Wests’ retractor if used should be frequently repositioned/de-tensioned to reduce the chance of iatrogenic skin damage.

    Once through the skin the fat is dissected to reveal the Extensor Digitorum Brevis(EDB) tendon (2) lateral to the Extensor Digitorum Longus(EDL) tendon (1).

    The incision should be extended proximally enough to encounter the muscle belly of EDB (1).

    The proximal end of the EDB is captured by a running 2.0 Ethibond suture, prior to dividing the tendon distal to the suture for transfer.
    This prevents the proximal end retracting which is key as once transferred the EDBr will be sutured back here.

    Proximal division of the EDB tendon, resulting in a long length of tendon distally to transfer.

    The EDB tendon is freed distally whilst which requires a small amount of careful sharp dissection away from the longus tendon (1) at the level of the MTP joint, whilst protecting its distal insertion.

    The 2nd MTP joint capsule is opened with a longitudinal incision , revealing the metatarsal head (2) and base of proximal phalanx (1) and allowing inspection of the joint and synovectomy as required.
    Given the MTP joint is deformed into varus the medial soft tissues will require releasing. This involves a careful sub-periosteal stripping of the collateral ligaments from distal to proximal, as well as releasing capsular attachments from the base of the proximal phalanx medially.

    If the varus deformity remains persistent a division of the medial MTP capsule transversely should also be performed.
    Care needs to be taken not to wonder plantar-wards with this cut which risks dividing the neuro-vascular bundle.

    A partial correction of the deformity at the level of the MTP joint is already visible and is accentuated by simulated loading of the forefoot with pressure exerted underneath the lesser metatarsal heads .
    The Extensor digitorum brevis tendon (EDB, 1) is yet to be transferred which will further improve the alignment , as will a repair of a plantar plate tear if present.

    Associated MTP joint hyper-extension is corrected by Z-lengthening of the EDL tendonThe first step is a midline division of the tendon into two equal halves.

    The Z lengthening of the Longus tendon continues by exiting the longitudinal cuts on opposite sides of the proximal and distal tendon.

    Attention is turned to the 2/3 web-space where If a neuroma is present this will be removed, care being taken at this stage to preserve some transverse soft tissue (1) that crosses the web space(if possible).Classically the transverse metatarsal ligament is the structure that the EDB is transferred beneath but try to preserve anything fairly robust superficial to this as well(the ligament is quite a way down and the tendon may not be of sufficient length to be transferred beneath it).
    At this stage the lateral capsule & plantar plate should also be inspected for tears and repaired. These will have been identified pre-operatively on ultrasound in most cases.

    The lateral capsule and plantar plate should be inspected for tears.
    A Watson-Cheyne probe (1) passes easily from the joint through the lateral capsular tear and helps identify capsular breaches.

    Some transverse metatarsal ligament remains intact (1) , between the second & third metatarsal necks. The EDB transfer will be routed beneath this.

    The EDB tendon (1)is routed beneath the transverse ligament (2), guided by the Ethibond stay suture previously placed, and run from distal back to proximal.
    A small tendon passing forceps or small mosquito artery clip is passed underneath the transverse ligament at point (2) initially to grasp the suture , then pull it and the tendon back proximally.

    The transferred EDB tendon , not yet re-connected proximally.
    If traction is now placed upon this suture the toe can be noted to correct further out of varus at the MTP joint level.

    Closure of any capsular or plantar plate tear (1) with one or two tightening 2.0 Vicryl mattress sutures is performed before the EDB transfer is tied back to itself.This allows much easier access to the capsule than trying to do this after the transfer has been tied back into position
    Care must be taken to avoid catching any of the transferred tendon

    With the capsule repaired & rebalanced and tendons transferred & lengthened (but not yet tied back together ) the deformity is looking well corrected. Traction upon the end of the re-routed tendon will give a good indication of the corrective effect of the transfer (seen here).
    This is just an axial view and of course the sagittal plane alignment must be also appropriate. In this case the PIP joint is a fixed and painful deformity that requires correction. This is not always the case.

    A standard PIP fusion is performed and a 1.6mm K wire driven across it (1) and also across the MTP joint(2) which is placed in a corrected position.
    A PIP joint fusion is not necessarily required unless deformity is also present there.
    The position of splintage of the MTP should be slight overcorrection (ie valgus & slight plantar flexion). The MTP joint can alternatively be splinted with the K-wire across the MTP joint after the EDB tendon has been tied off first (as per the next slide).
    In splinting across the MTP joint its surfaces should be distracted slightly.

    The two ends of the EDB (both with 2.0 Ethibond sutures in situ ) are now brought together & tied, which is often fairly tight. It is very important however that the tendons are not tied into extension but are kept neutral in the sagittal plane.I tend to use additional oversew of interrupted 2.0 vicryl sutures, once the 2.0 Ethibond has been tied off, to strengthen the repair. Finally the Z-lengthened longus tendon is repaired under appropriate tension.
    With poor soft tissues the situation may occur where a “piggy-backing” of the brevis transfer onto the longus is something I would consider.

    The on-table images of the “cross-over “second toe deformity , before Extensor Digitorum Brevis transfer.

    The on-table images of the “cross-over “second toe deformity , after Extensor Digitorum Brevis transfer and associated procedures.

    Post Operative

    The patient can weight-bear as soon as nerve blocks worn off
    They need a stiff soled shoe for 5 weeks post surgery
    The initial 2 weeks (at least) should be with a post-operative type Velcro-fastening shoe
    Beyond this a fit-flop or equally stiff soled shoe is acceptable
    An X-ray is required post-operatively if a K-wire has been inserted and also should be repeated prior to K-wire removal in particular if a PIP joint fusion has been required.
    Dressing changes/ wound cleaning at 1 & 2 weeks , during which a wool & crepe bandage is also applied in the outpatients
    After this the patient should change dressings alternate days , keeping wounds covered to avoid them rubbing on shoewear
    The foot may be showered from 3 weeks post operatively
    K wire is removed at 5 weeks post-op .The published papers suggest 3 weeks and thereafter corrective strapping. Certainly a balance needs to be struck between correction ,recurrence and symptomatic joint stiffness.
    The second toe should be strapped in the corrected position using a daily change of Micro-pore tape, for 6 weeks after K-wire removal.
    Physiotherapy is useful from a few weeks after K wire removal to work on MTP mobilisation to help improve control & strength of the toe and reduce stiffness.

    Recommended Reading

    Results of flexor to extensor and Extensor Brevis tendon transfer for correction of the crossover second toe deformity.
    Foot & Ankle Intl. 1999. 20 (12) .781-788
    Haddad S L, Sabbagh R C, Resch S , Myerson B, Myerson M S.
    35 feet were followed up at approximately 4 years after surgery.
    The authors’ grading system classifies the deformity into 4 progressive stages starting with synovitis and mild MTP varus and ending with frank MTP dislocation. 2 separate techniques were used, either a standard FDL flexor to extensor transfer (for grade 3 & 4 deformities) or the EDB transfer. In both cases a K wire was left in situ for 3 weeks after which corrective taping was attached for 6 weeks.
    24 patients were satisfied with respect to the correction. Pain relief was complete in 22 patients and correction of deformity complete and permanent in 30.
    Concurrent interdigital neuroma and MTP joint instability: Long term results of treatment.
    Coughlin M J, Schenck R C, Shurnas P J, Bloome D M.
    Foot & Ankle Intl 2002. 23(11):1018-1025.
    A cohort of 121 patients with a mortons neuroma are reported upon. In 20% of these there was capsular instability to the extent that surgical correction of this was also required. Approximately 90% were available for follow up. 85% of patients felt the results were good or excellent though just less than 30% had some ongoing symptoms.
    The operation used was in 4 a capsular release dorsally and plication with extensor lengthening. In 12 patients a flexor tendon transfer was added to this and in 5 cases the EDB transfer was added to the preceding 2 interventions. K wiring was again for 3 weeks.

    Reference

    • orthoracle.com

    Tags:

    You might be interested in

    Dark mode powered by Night Eye