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Lapidus procedure- (fixation using crossed screw technique)

    Overview

    Learn the Lapidus procedure: (fixation using crossed screw technique) surgical technique with step by step instructions on OrthOracle. Our e-learning platform contains high resolution images and a certified CME of the Lapidus procedure: (fixation using crossed screw technique) surgical procedure.
    An operation for correction of hallux valgus deformity with a hypermobile MTC joint or in the patient with recurrence after previous hallux valgus surgery.
    This is a midfoot operation and as such post-operative mobility is severely limited for the initial 6 weeks ,usually in a cast and non-weight-bearing. Overall return to normal function is more protracted than for a standard osteotomy and soft tissue correction.
    It is unforgiving if not positioned correctly and Hallux Valgus recurrence is still described after the operation.

    Indications

    INDICATIONS.
    -Hallux Valgus deformity with a hypermobile first MTC joint (or associated first MTC arthritis).
    -Hallux Valgus deformity with generalised ligamentous laxity
    -Salvage for recurrent Hallux Valgus
    SYMPTOMS & EXAMINATION.
    It is worth being aware of factors that are are recognised as being risk factors for recurrence of a Hallux Valgus deformity and actively looking for these when considering the primary operation to be used in its correction. The particular consideration is whether a standard osteotomy and soft tissue correction is likely to end in recurrence . Soft tissue laxity and overt ligamentous hypermobility are two recognised conditions which would therefore be relative reasons to consider a Lapidus procedure. Neurological compromise , Rheumatoid arthritis and osteoarthritis of the 1st MTP joint are also conditions recognised as being associated with recurrence though would not necessarily be indications for a Lapidus procedure.
    How 1st MTC hypermobility is defined is open to interpretation. 10mm plus of translation in the sagittal plane is one definition (approximately a thumbs breadth). The joint can also be hypermobile in the coronal plane too of course. The reader will not mind being reminded of Mortons theory of the short and hypermobile 1st ray leading to medial column collapse , pronation and Hallux Valgus occurrence.
    A review of the papers in the results section will help put the outcomes and recovery after these midfoot operations in their appropriate context. They are more significant interventions in many than more standard Hallux Valgus osteotomies and soft tissue corrections. Recurrence rates of up to 20% are reported in some series , non-union occurs and a return to full function can be very protracted compared to standard surgeries.
    INVESTIGATIONS.
    X-Ray: Standard AP and Lateral weight-bearing films are generally sufficient .
    There are measuring “rigs” described in the literature to measure MTC hypermobility which in practical terms are of use in the research situation only.
    OPERATIVE ALTERNATIVES.
    In the patient with recurrence after Hallux valgus surgery it should be appreciated that a Lapidus is only one option. If recurrence is due to technical inadequacies with the initial operation then (bone stock permitting) redoing an osteotomy and soft tissue procedure correctly may be all that is required.
    A corrective MTP joint fusion is also an appropriate intervention for recurrent Hallux Valgus (though fewer papers published on its use for this indication than are available for Lapidus).

    Setup

    General or Regional anaesthetic
    Antibiotics & LMW Heparin on induction
    Laminar flow theatre if available
    Thigh tourniquet (ankle tourniquet gets in the way of positioning the wire driver and drill during fixation)
    Patient supine
    Pre/post operative Nerve block (popliteal and / or inter-metatarsal )for analgesia

    Operation

    The main skin incision used is at the base of the first metatarsal. It is dorsally placed and should also allow access to the base of the 2nd metatarsal .
    Incisions will also be required in the 1st web space distally for a modified McBrides procedure and the medial aspect of the 1st MTP joint to excise any residual medial bone and plicate and close the medial capsule under appropriate tension.

    Deep dissection is to the lateral side of the Extensor Hallucis Longus tendon to expose the 1st tarso-metatarsal (TMT) joint.
    Often the neurovascular bundle lies between the Extensor Hallucis Longus (EHL,1) and the Extensor Hallucis Brevis tendon(EHB, 2).
    In this case however it does not and will therefore sit lateral to the EHB tendon.

    The first metatarso-cuneiform joint is exposed sub-periosteally.
    Full thickness skin flaps are raised and care taken to sit self retaining retractors well beneath the skin edges. The EHL tendon (1) and EHB tendon(2) are retracted to give good access to the 1st metatarsal base ( 3 ) and medial cuneiform ( 4 ).

    The hypermobility of the first TMT joint is easily demonstrated on-table, holding the first MTP immobile and loading through the MTC medio-laterally (though sagittal plane instability is the more normal criteria for diagnosis).

    The hypermobility of the first TMT joint is easily demonstrated on-table , keeping the position of the First MTP immobile and loading through the MTC medio-laterally.

    The TMT joint is prepared back to subchondral bone using small Lambotts osteotomes (as here) as well as a 5mm high speed burr if bone is hard. Here you can see the chondral surface of the 1st metatarsal and a small layer of attached subchondral bone being carefully debrided as a single section. A very small laminar spreader is useful for this stage though take acre to avoid crushing the bone ends as there is not much length relatively to play with. This is true with respect to all bone preparation at the 1st MTC. The joint is deep and its full extent must be visualised and prepared. If the joint is not taken back equally on both sides then there will be a tendency to deformation during fixation. If the plantar aspect of the joint is not prepared proportionate with the dorsal aspect then the MTC joint will tend to compress into dorsi-flexion during fixation .This will defunction the first ray and tend to reduce the medial arch profile. To produce appropriate correction of a deformity the two articulating surfaces may need to be differentially prepared.

    The MTC joint is placed in an optimal position (in the medio-lateral and saggital planes) once prepared and held temporarily with K-wires(1) as definitive fixation occurs.
    Metatarsus varus should be completely corrected. If the 1st MTC joint is mobile (as with this case) this is simply a question of positioning the “minimally” prepared joint. On occasion the 1st Metatarsal varus may be fixed in which case a wedge of bone will need to be excised to correct the deformity. Neutral rotation
    and adequate(but not too much) plantar flexion of the metatarsal also need to be ensured .
    As with all fusion work it is important to both achieve good bone to bone contact as well as an appropriate position.
    With a 5mm high speed burr (2) a dorsal trough is made proximally on the first metatarsal cortex. Without this trough the screw head will impinge upon the dorsal cortex before it is fully seated and prevent compression.
    The trough should be a few cm distal to the joint line to avoid fracturing into the joint as the screw is driven home.
    The medial cuneiform is marked 3.

    The first (lagged) full cancellous screw being inserted. The trough has initially been drilled through across to the medial cuneiform ,then over-drilled proximally. This is perhaps better done over a K-wire using a cannulated screw system. Note the plantar angulation of the screw. Orientation of the metatarsal should also be controlled manually during screw insertion (as well as by the K wire).

    A second screw is inserted ,orientated to miss the first. Again a lagged full cancellous screw is used. If the indication for the Lapidus procedure is ,as here, recurrent Hallux valgus with TMT hypermobility then distal soft tissue procedures(a modified McBrides and Medial capsular plication)will also be required.
    There are alternate forms of fixation which may be used , in particular dorsal wedge type plates if a significant degree of planus deformity is being addressed .
    It is not uncommon practice either to add a third screw to hold the relationship between the 1st and 2nd metatarsal bases. The adjacent border of the 2nd metatarsal can be prepared at the time of 1st MTC preparation also.

    Post Operative

    Day-case or overnight stay
    LMW Heparin 2 weeks
    The initial 4-6 weeks are non-weight-bearing and spent in light-weight cast.
    (It is important to regard this as a mid-foot and not a forefoot operation re progression of weight-bearing post-operatively).
    Change dressings at 1 and 2 weeks
    Check X-Ray and clinical review is required at 6 weeks to confirm adequate progression of bony union.
    If this is the case then a long post-operative boot and off the shelf semi-rigid FFO type orhotic is worn for a further 6 weeks. Beyond this a stiff soled form of shoe-wear will be required such as a Fit-flop or substantial walking shoe. The alternative would be a stiff soled hiking type boot.
    Appropriate shoe-wear fit and support is vital in the forth post-operative month
    The use of a semi-rigid FFO orthotic is helpful until 4 months post-op.
    Avoid gym activities for 3 months

    Recommended Reading

    Modified Lapidus procedure for the treatment of hypermobile Hallux Valgus. Foot & Ankle International. 2000.816-821.
    P.A.Bednarz , A.Manoli.
    31 feet followed up over average of 46 months
    Average 10 degrees improvement of inter-metatarsal angle
    Full recovery fairly slow with 8 average months until full sporting activity or equivalent was possible.
    5 recurrent deformities (almost 20%).
    The Lapidus procedure as salvage after failed surgical treatment of Hallux Valgus. J Bone Joint Surg. 85-A. 2003. 60-5.
    Coetzee CC, Kuskowski MK.
    24 persons , 26 Feet. All Hypermobile Hallux Valgus recurrences. Hallux Valgus angle improved from 37 degrees to 17 and Inter-metatarsal angle from 18 to 8.6 degrees. 77% Very Satisfied, 4% Satisfied. No recurrences but 3 non-unions.
    Long term results of the Hohmann and Lapidus procedure for the correction of Hallux Valgus. J Bone Joint Surg 2013; 95-B:1222-6.
    Faber et al
    Prospective randomised controlled trial in which 45 patients underwent a Lapidus (76% of whom were hypermobile) and 46 underwent Homans osteotomy (64% of whom were hypermobile).
    The Lapidus groups Hallux Valgus & Inter-metatarsal angles improved from 33.8 & 13.9 degrees to 13.5 & 5.7 . The Homan groups Hallux Valgus & Inter-metatarsal angles improved from 31 & 11 degrees to 13 & 6.3 .
    Patients reviewed at both 2 & 10 years and no change noted in the outcome over time.
    Recurrence 9% in both groups and unsatisfactory subjective result was 20% also in both groups.
    First metatarsophalangeal joint arthrodesis as a treatment for failed Hallux Valgus surgery.
    Foot & Ankle Int. 2009
    Grimes JS, Coughlin MJ.
    33 Feet, 55% with recurrent deformity as the indication for fusion .
    88% satisfaction with correction after fusion . However overall satisfaction rates were slightly lower.
    39 rated as excellent (85%) ,33 Good(10%) & 24% Poor.

    Reference

    • orthoracle.com

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