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First MTP Fusion- Revision of failed Kellers using DocPrice plate and vascularised allograft

    Overview

    Learn the First MTP Fusion: Revision of failed Kellers using DocPrice plate and vascularised allograft surgical technique with step by step instructions on OrthOracle. Our e-learning platform contains high resolution images and a certified CME of the First MTP Fusion: Revision of failed Kellers using DocPrice plate and vascularised allograft surgical procedure.
    The technique described is a lengthening osteotomy of the first metatarsal combined with an intercurrent metatarsophalangeal joint fusion. It is indicated for cases in which the 1st metatarsophalangeal joint (MTPJ) has been excised. This is most commonly carried out with a Kellers resection arthroplasty but may also result from a failed 1st MTP joint replacement in which there is resulting bone loss.
    Keller was an American surgeon who popularised an excision arthroplasty of the 1st Metatarsophalangeal joint (MTPJ) for hallux valgus in his report 1904. The operation was originally described by Davis-Colley in 1887. The operation was widely carried out in the first half of the 20th century and further modifications which involved a greater resection of the proximal phalanx (Bonney and Macnab 1952) and stabilisation of the pseudojoint with a K-wire (Fitzgerald 1950) further promoted its use.
    However over the later part of the last century more modern techniques surpassed the Keller excision arthroplasty with more predictable results and avoidance of the complications of a short great toe, the dorsiflexion deformity which was common (cock up deformity) and transfer metatarsalgia some years after the procedure; all of which became widely reported.
    Kellers procedure became historic and was reserved mostly for use in the elderly and low demand individual. The author infact has never carried out a Kellers procedure for hallux valgus because of the unacceptable longer term results.
    This case is a 70 year woman presenting with a long history of recurrent deformity, painful pseudoarthrosis and most recently transfer metatarsalgia. She had had little respite with the use of orthotics or shoe modifications
    The options open to her operatively were discussed but we decided to try to preserve the length of the great toe and provide a stable arthrodesis without the additional need for bone graft or bone substitute.
    Dr Marcus Preis from Wiesbaden in Germany has popularised the DocPrice technique to restore length to a first ray at the time of fusion after Kellers resection arthroplasty. He has personal experience of more than 100 cases (author’s personal correspondence). The dorsal half of the metatarsal is transported distally on the lateral soft tissue mass in which the blood supply is held. This creates a stable bridge and obviates the need for autograft. The gaps which remain on the proximal dorsal metatarsal and the joint fusion site on the plantar side do not require grafting but fill in over time.
    The DocPrice plate has specific features to allow for a stable fusion in that it has strong 3.5mm locking screws proximally and 2.7mm locking screws distally. Because the shaft of the 1st Metatarsal remains intact on the plantar side there does not need to be extensive fixation proximally, though the gap which results dorsally from the graft translation does need to be bridged. There are no other devices available which are specific to this operation and though other rigid locking plates could be used my concern would be residual hardware prominence distally.
    The technique is described in the German textbook Vorfusschirurgie, Springer Verlag 2012, edited by Sabo and Diserderius.
    Readers may also find the following OrthOracle techniques of interest:
    https://www.orthoracle.com/library/bone-block-first-mtp-fusion-using-the-wright-ortholoc-plate/
    https://www.orthoracle.com/library/hallux-varus-correction-stryker-anchorage-mtp-arthrodesis-plate/
    https://www.orthoracle.com/library/first-mtp-big-toe-fusion/ and
    https://www.orthoracle.com/library/first-mtp-fusion-coughlin-reamer-preparation-and-orthosolutions-cannulated-4mm-screws/

    Indications

    INDICATIONS
    This technique is used as salvage of the short and painful 1st MTPJ after an excision arthroplasty in the manner of a Kellers or after a failed joint replacement where there is bone loss. The options for salvage include a bone block arthrodesis with a synthetic material or a tri-cortical bone graft taken from the iliac crest or fibula. These options risk non union at one or both ends of the graft which commonly occurs and carries risk of complications, particularly pain, at the graft harvest site. This technique avoids graft harvest site problems and because the graft is vascularised it results in a high union rate. The length that can be restored is limited to 15mm because the lateral vascular pedicle cannot be distalised more than this in my experience.
    SYMPTOMS & EXAMINATION
    The symptoms resulting from a short and unstable 1st MTPJ after resection arthroplasty are typical in this case. This 70 year old lady had a Keller’s procedure more than 35 years ago for hallux valgus. She presents with typical features of a cock up toe – in which there is dorsal impingement of the hallux on foot wear. Also resulting from the short and relatively unstable toe (see the pre-operative images) there is transfer of load on weight bearing resulting in transfer metatarsalgia; that is pain and callosity under the lesser metatarsal heads.
    IMAGING
    Pre-operative standing antero-posterior (AP), lateral and a non weight bearing oblique all help to define the deformity as well as the degree of shortening of the first ray. In this case the stump of the proximal phalanx is very short but the inter-phalangeal joint (IPJ) can be seen too. I do not routinely do any other images as I find that plain radiographs are all that are needed. This case represents about the minimum length of residual phalangeal stump that the author would attempt this procedure apon.
    ALTERNATIVE OPERATIVE TREATMENT
    In order to relieve both pain from the pseudo-arthrosis and very importantly to get a stable ray that can off load the lesser metatarsals, where the transfer pain of metatarsalgia arises, operative treatment needs to result in a stable union of the 1st MTPJ.
    Reports of revision Keller’s procedure yielded less good results compared to arthrodesis (Machacek et al).
    There is not enough stump in the P1 to support any form of joint replacement. In order to restore length of the MTPJ, techniques have been described using a tri-cortical bone graft from the iliac crest (Bhosale et al). This technique, however, risks the complications of iliac crest grafting and pain from this area can be persistent and disabling. The use of bone substitutes has also been described. The DocPrice plate technique, however, requires no distant graft but relies on local bone transport with the lateral blood supply to the dorsal shaft being preserved.
    NON-OPERATIVE MANAGEMENT
    Non-operative treatment may be provided with the use of orthotics which aim to stabilise the first ray and at the same time off load the weight from the lateral rays. Bespoke shoes may be required if the toe is very dorsiflexed to accommodate for this.
    CONTRAINDICATIONS
    Predominantly this operation would be contraindicated if all other operative care was also contraindicated, for example if the skin or circulation were inadequate to gain healing. Vascular status of the limb needs to be assessed clinically or with dopplers if there is concern regarding distal limb circulation. Smoking increases the likelihood of non-union and so may be a relative contraindication to surgery. The stump of the proximal phalanx needs to be large enough to take the two most distal screws of the plate so that the IPJ can be preserved. If the stump is too small then any fusion procedure will have to also sacrifice motion of the IPJ.

    Salvage of a failed Keller resection arthroplasty. Machacek F, Easley ME, Gruber F, Ritschl P and Trnka HJ. JBJS(Am) 2004 Jun:86(6):1131-8
    Complex primary arthrodesis of the first metatarsophalangeal joint after bone loss. Bhosale A, Munoruth, Blundell C. Flowers MJ, Jones S and Davies MB FAI 2011 Oct:32 (10):968-72

    Setup

    The patient is positioned supine with the foot at the end of the table. I prefer to use a tourniquet to improve my view of the operative field but if there are concerns regarding circulation then the tourniquet is not essential. Choice of anaesthetic depends on the local preference, but as no bone graft is needed from the iliac crest, a regional technique is our preferred option.
    Image intensifier may be used to ensure position of hardware and screws but I do not routinely use this.

    Operation – 1

    The plain X-ray shows almost complete absence of the proximal phalanx following a severe Kellers excision arthroplasty.

    The old skin incision may to be incorporated into a new longer incision that allows access to the shaft of the 1st metatarsal.The old incision is neither classic medial or dorsal but rather in between. I therefore decided to make the distal limb of this transverse across the toe laterally so that a full thickness flap would preserve the blood supply here.
    The medial cutaneous branch of the superficial peroneal nerve is at risk here especially when there is scarring. I intend to elevate the nerve with this flap but have counselled my patient carefully about the high risk of some distal sensory loss.

    The skin is often delicate in revision situations and I prefer to minimise skin edge handling by using skin hooks when possible rather than forceps.

    Sharp dissection is used to elevate a dorsal flap of skin and fat which will include the medial cutaneous nerve.The nerve is not exposed directly as I am concerned that to do so would risk vascular damage to the nerve. Particular care is taken at the distal end of the wound where the nerve will be most at risk.
    The capsule of the pseudo-joint is thus exposed and will subsequently be repaired to provide a robust layer over the arthrodesis.

    The capsule is incised again as a layer in-line with the skin incision.The pseudo-joint is made up of a knot of fibrous tissue (F) which is excised to reveal the metatarsal head (M1) and the stump of the proximal phalanx (P1)

    All of the interposed soft tissue is excised so that the M1 can be docked onto the P1 once both surfaces have been prepared and without soft tissue being in the way of a successful union

    Once cleared of fibrous tissue, both bony parts of the articulation can be fully exposed by plantar flexing the joint.The phalangeal remnant (A) is outlined here with skin marker to make it clearer for the purposes of demonstration.

    The proximal phalangeal remnant is then prepared for fusion with rongeurs and a drill or a K-wire.I would not recommend small joint reamers due to the short nature of the stump and the risk of excessive reaming.
    I prefer to use a low speed 2mm wire to create multiple fenestrations in order to minimise the loss of bone. The wire is drilled in 5mm deep and irrigated to prevent heat generation.

    The resulting ‘pepperpot’ surface of the phalanx can be seen here. These holes can be easily joined up with a small sharp rongeur if the surface is not cancellous enough. I was satisfied here that enough was prepared. The curved surface fits well with that of the metatarsal head in its unprepared state.

    The metatarsal head needs to be taken back to healthy subchondral bone with bone nibblers.Attention is then turned to the metatarsal head, Again length preservation is key. Once again small joint reamers are not used. Instead I use sharp rongeurs and carefully remove the sclerotic bone surface to expose cancellous bone, especially on the dorsal half of the head as this is the area that will be moved distally to dock with the phlangeal remnant and provide a union surface.

    Before the metatarsal osteotomy is made an appropriate size plate is selected.Zimmer Biomet now provide the DocPrice Plates for this operation, formerly they were manufactured and provided by Normed. The plate has 3.5mm locking screw fixation to the shaft of the metatarsal and 2.7 locking screw fixation points for the phalanx. This provides a robust plate but the plate needs careful selection so that the screw holes are appropriately placed and the plate is the correct length.
    Plates are sided so that optimal screw orientation is provided proximally and distally. In this case a Large right plate is selected (L refers to Large not Left – the side is written in words; in this case “RIGHT”)
    Note the plate is a composite plate with the gold part accepting gold coloured 3.5mm locking screws and being thicker than the distal blue end which takes blue 2.7mm locking screws.


    There are 3 sized implants for each side (6 in total) that come on one set with the screws – though some countries now require sterile separately packed items.
    The plate has 3.5mm locking screw fixation to the shaft of the metatarsal and 2.7 locking screw fixation points for the phalanx. Plates are sided so that optimal screw orientation is provided proximally and distally.
    Note that L refers to Large not Left – the side (Left or Right) is written in words. There is no such confusion for Medium (M) and Small (S) plates.

    The osteotomy limbs are marked out on the metatarsal taking account of where the plate will be situated.The longitudinal osteotomy limb(1) is along the midaxis of the metatarsal, parallel to the plantar surface of the foot, and exists distally through the metatarsal head.
    The proximal osteotomy limb(2) is made 90 degrees to this axis.
    Care must be taken not to disrupt the soft tissues attached on the lateral part of the metatarsal (L) as this is the area where the blood supply to the bone is situated.

    The horizontal osteotomy is made first with a small saw blade.Dyonics and DeSouter make good electric saws for this. The whole width of the metatarsal is cut and the osteotomy exits through the midaxis of the metatarsal head. Do not lever the osteotomy or a fracture may be propagated into the 1st tarsometatarsal joint.

    The 90 degree proximal osteotomy is carried out making sure that only the dorsal half of the metatarsal is cut.The dorsal fragment is now free to move. Occasionally a mini-lambotte osteotome is used to assist in mobilising the dorsal fragment.

    The osteotomy is mobilised with a laminar spreader inserted proximally.Maximal transport of the dorsal fragment is limited by the tension at the fusion site
    In other words there is a limit to how far the toe can be moved distally due to soft tissue tension in the flexor and extensor tendons and the skin. Also the mobility of the dorsal segment is bound by the freedom of soft tissue attachments laterally. I have found that 1cm is easy to achieve usually but more than 1.5cm is not possible. In this case around 10mm felt right for soft tissue tension and restored the toe length appropriately. This is judged clinically though an image intensifier could also be utilised.
    Care needs to be taken not to damage the dorsal proximal part of the metatarsal with over distraction.
    If concerns have been raised pre-operatively about circulation then at this stage the tourniquet (if one has been used) can be released and the prepared end of the graft inspected for bleeding. This is not my usual practice as I have not witnessed any difficulty with vascularity of the graft post-operatively and avoid cases where the circulation is suspect pre-operatively.

    Note the compression achieved at point A once the graft has been docked distally. The mobilised segment is temporarily held with single ended 1.4mm k wires as shown. These are usually introduced whilst the laminar spreader holds the distraction. It can be tricky to make sure these wires are not in the way of subsequent plate application. Often they need to be moved or added to.

    The toe is temporarily held with one or two k-wiresOnce the plate is applied and close apposition to the bones checked, it is vital to make sure that the fusion is correctly orientated. I use a simulated weight bearing surface (the lid of the DocPrice plate set works well) to ensure the toe has contact in neutral ankle position – in other words is the cock up deformity is corrected?

    I also ensure that the valgus deformity is corrected as shown. The toe may look somewhat varus due to the windswept nature of the lesser toes. Position is up to the surgeon and it of course helps to see what position the patient wishes before surgery.

    One of the k-wires is adjusted to go through the plate and to make sure the plate orientation is perfect. This is the last chance to check this before fixation with screws starts. There is not much latitude in screw position so it is vital to get this all correct before stabilisation.

    The most proximal screw is selected to start with – this will be a 3.5mm screw and the drill is 2.7mm in diameter.Threaded drill towers ensure the direction of the drill allows good locking screw orientation. Note the drill tower has a gold stripe (G) to ensure the correct tower for the gold coloured 3.5mm screws is selected. These are fixed angle devices with no poly-axial element to the screws. Bicortical drilling is required for maximal hold.

    Screw depth is measured with a traditional type depth gauge, and the initial screw inserted.Bicortical length is selected.

    The screw is tightened fully and locks very flush into the plate. No prominence is acceptable and prominence will be poorly tolerated.

    Distal fixation follows with 2.7mm diameter locking screws.The screws are blue in colour to distinguish them from the gold coloured 3.5mm screws. Again with orientation being determined by threaded drill towers (with a blue stripe – B) and drilling this time with a 2mm drill.

    Fixation continues across both the mobilised graft as well as distally and proximally. I use every screw hole that will add security to the construct. The graft does not need compression in the dorso-plantar plane, but just stable fixation to unite – rather like for a scarf osteotomy.
    However the long slot in the plate can be used for oblique screws to facilitate compression at the arthrodesis if the stump of the phalanx is long enough to allow this. In this case there was not sufficient bone. The lengthening of the graft segment though in effect compresses against the short phalangeal remnant sufficiently here.

    Operation – 2

    The position is checked with a simulated weight bearing flat surface to ensure toe contact is made with the foot and ankle neutrally aligned.If the position of the toe is not correct in the sagittal plane then the plate can be contoured carefully at the level of the arthrodesis prior to definitive fixation. Plate bending forceps are included in the set to allow for this. Repetitive bending and unbending is to be discouraged though as this will fatigue the plate.

    I have elevated the toe here using forceps on the nail to show that there is clearance in dorsiflexion too at the IPJ and to make sure there is no IPJ plate impingement dorsally. This range of motion is important for good gait as well as allowing a shoe with a standard heel to be worn.

    The wound is carefully closed in layersCareful closure of the dorsal capsule is possible with minimal tension due to the low profile nature of the plate.
    The extensor hallucis longus (EHL) tendon is still in this soft tissue and not allowed to bowstring in the wound as this might hamper wound healing.

    I prefer to close the skin with interrupted monocryl sutures to prevent wound tension but to allow haematoma to leak out onto dressings rather than be contained and cause potential inflammation or wound breakdown.
    The repair must be tension free in such vulnerable soft tissues. The sutures take around 6 weeks to fall off the skin.
    Wound is dressed with jelonet, gauze and a bulky bandage of velband and crepe is then used.

    It is worth recalling the pre-operative starting point in terms of the forefoot deformity.

    Images taken at 6 weeks and prior to wire removal from the lesser toes show appropriate alignment of the hallux.
    Union is yet to be established but the patient has a painless, stable toe and a well healed wound. The wires are removed and free mobilisation in now permitted

    A fusion using the DocPrice plate at 3 months post-operatively.
    The oblique holes in the plate have been used here to augment the construct and provide for some compression. This is possible when there is enough phalangeal remnant to allow for this.
    Image Courtesy of Dr Marcus Preis.

    A fusion using the DocPrice plate at 3 months post-operatively.
    The gap in the dorsal cortex where the graft has been advanced can be seen at point A. This will fill in over time and does not separate autograft.
    The oblique screws can be well seen on the lateral image.
    Image Courtesy of Dr Marcus Preis.

    Post Operative

    The surgery is done as a day case and the patient returns home with adequate oral analgesia as required.
    Mobility instructions are to keep the limb elevated most of the time for the next two weeks. They may mobilise fully weight bearing in a rigid soled shoe but I advise that they only hang the limb down for a maximum of 5 minutes in any hour. I call this “tea-toast-toilet” mobility as this is about all they can do! I am not concerned about the strength of the plate and osteotomy construct with this plate system and do not therefore protect the weight bearing status of the patient.
    Dressing are left as from theatre for 2 weeks and are kept dry
    2 weeks: The patient returns for dressing removal at 2 weeks and they are given wound care advice – shower not bath, dry wound with a cold hairdryer and keep it covered with gauze and a sock. Mobility improves but they must keep the rigid soled shoe on for a further 4 weeks. I ask them to walk but to rest up if there is pain and/or swelling.
    6 weeks: Next review is at 6 weeks with AP and lateral radiographs. If wound is doing well and radiographs are satisfactory then I allow free mobilisation into a supportive shoe such as a trainer.
    6 months: I will make a final review at 6 months with radiographs only indicated if there are ongoing symptoms. Patients are discharged at this appointment if all is well.

    Recommended Reading

    There are are no peer reviewed publications on this technique to date.
    Complex primary arthrodesis of the first metatarsophalangeal joint after bone loss. Bhosale A, Munoruth, Blundell C. Flowers MJ, Jones S and Davies MB FAI 2011 Oct:32 (10):968-72
    This series by the author and colleagues in Sheffield was our attempt at quantifying the use of a bone block from the iliac crest. Results were satisfactory and prior to the DocPreis Plate this was all we had. There was one non-union out of 10 cases of failed Kellers or joint replacement.
    Salvage of a failed Keller resection arthroplasty.Machacek F, Easley ME, Gruber F, Ritschl P and Trnka HJ. JBJS(Am) 2004 Jun:86(6):1131-8
    These authors have made a comparison in outcomes between repeat Keller’s resection or arthrodesis in patients with residual problems (cock up toe, transfer metatarsalgia etc) after Keller’s resection. Satisfaction was far better in the arthrodesis group despite the fact that they they had a re-operation rate of 17% for mal or non-union.
    Keller’s arthroplasty in adults with hallux valgus and hallux rigidus. Putti AB, Pande S, Adam RF and Abboud RJ. Foot Ankle Surg 2012 Mar;18(1):34-8
    Professor Abbouds team, from Dundee University, have reviewed outcomes for Keller’s procedures and found acceptable results. They report significant number of complications but do not associate these with poorer outcomes. They suggest that the procedure has a role in patients with degenerative hallux valgus, their patient’s mean age was 62.5 years.

    Reference

    • orthoracle.com

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