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Hallux Rigidus- Modified kellers arthroplasty

    Overview

    Learn the Hallux Rigidus: Modified kellers arthroplasty surgical technique with step by step instructions on OrthOracle. Our e-learning platform contains high resolution images and a certified CME of the Hallux Rigidus: Modified kellers arthroplasty surgical procedure.
    Historically an operation which has been used across the age spectrum for Hallux Valgus correction , especially in Europe.
    The published results and its joint sacrificing (and sometimes first ray defunctioning) nature mean its use in all but low demand and elderly patients is usually avoided.
    Modern surgical techniques for Hallux Valgus and Hallux Rigidus have seen it largely superseded apart from use in lower demand patients with poor bone quality likely to give issues with a corrective fusion

    Indications

    An operation very much for the older and less active patient with Hallux valgus or Hallux rigidus
    What has to be weighed up against its advantages (namely that it is undoubtedly effective in both deformity correction and pain relief , easy to perform and requires little active patient participation in the recovery phase ) is the fact that it can be significantly defunctioning in terms of 1st ray function (see results section).
    Historically it has been used for wider indications , notably in younger and more active patients. Though transfer metatarsalgia due to a potentially defunctioned 1st ray is a real risk there are undoubtedly younger patients who have done well in the longer term.
    Though the 1st MTP joint remains mobile following surgery this is not an especially useful in particular in the context of any compromise in 1st ray function.
    If the operation is being used to correct a severe Hallux valgus then consideration should also be given to a “‘binding” type procedure to hold the 1st metatarsal into a reduced position back towards the 2nd metatarsal .This is using an trans-medullary suture such as a small Arthrex tight-rope or similar.


    Setup

    General or Regional anaesthetic
    Antibiotics & LMW Heparin on induction
    Laminar flow theatre if available
    Ankle tourniquet
    Patient supine
    Pre/post operative Nerve block (popliteal and / or inter-metatarsal )for analgesia

    Operation

    A medial midline skin incision is used. Its length and extent is more akin to that used for an MTP fusion rather than a corrective first ray osteotomy. That is to say proximally it extends to the neck of the metatarsal and distally almost the length of the Phalanx.
    Once through the skin a scissors dissection should be used to define the Dorsomedial cutaneous nerve which sits in a fine fascial layer and can be reflected off the underlying capsule.
    In severe deformity a second incision may be required in the first web space for a modified McBrides procedure.

    A horizontal capsulotomy is first performed (not shown) , ensuring good full thickness capsular flaps result which can be used for a robust medial plication at the end of the procedure.
    A good length of proximal phalanx(1) is exposed medially as well as the lateral extent of the base of the bone. This exposure is aided by using either a McDonalds'(2) or small Homans’ retractor.
    The plantar attachment of the capsule and a small length of the short flexor attachment(marked in red) should be freed from the base of the phalanx (3) to aid in its retraction and protection during excision of the base of the phalanx. It is important that only a limited amount of the plantar soft tissue is released as its attachment will be required to aid in the effective reefing of the medial capsule as part of the soft tissue correction. A similar amount of dorsal soft tissue also will be reflected from the base of the phalanx. The long & short flexors and extensors of the hallux are at risk and should be protected.

    The articular surface at the base of the proximal phalanx is removed(1). This is done using an oscillating saw which should have limited medio-lateral travel (otherwise the risk to plantar and dorsal tissues is increased). The plantar(2) and lateral soft tissues are protected using Homans retractors.
    The far lateral cortex is divided with careful probing cuts rather than being plunged through (which risks damaging the lateral plantar neuro-vascular bundle).
    The amount of bone to be removed can be just beyond the most concave point of the articular surface.
    Certain published advice suggests far more of the base of the phalanx should be excised but with little objective evidence that this is required. The cosmetic and functional effects upon the Hallux is predictable if too much bone is removed.
    The objective should be to provide adequate and easy space for the soft tissue interposition whilst preserving some useful soft tissue tension.

    The articular surface being removed.
    How much to remove is open to debate but it should be fairly conservative. The more that is excised the more defunctioned the first ray may become. An often quoted figure is one third of the Phalanx but that is a fair amount.
    Once this step has been performed an assessment can be made of the correctability of any valgus deformity. If there is still a strong tendency to deformation a lateral release can be added (either by a discreet dorsal approach or an intra-articular vertical cut through the lateral capsule which is easiest performed with the MTP joint distracted ).

    If treating a Hallux Valgus the medial eminence (1) of the first metatarsal should also be removed. This cut is made in line with the metatarsal shaft.

    At this stage a stout 1.6 mm K wire is placed along the length of the toe (exiting central/dorso-central through the base of the Phalanx)
    It is not yet driven across the MTP joint.

    A 1 Vicryl suture is sewn initially into the midpoint of the plantar capsule (2). This is then sewn into the dorsal and distal capsule overlying the metatarsal head which is consequently pulled partially into the joint space as the interposition material .
    If space permits it is useful to have a second separate suture also locked into position for ensuring good fixation of the capsule in the next stage of the operation.
    It is necessary to first release the capsule from its lateral attachments to both the metatarsal head and the proximal phalanx with longitudinal dissection.
    Subsequently a transverse cut is made through this dorsal capsular flap fairly distal on the dorsal aspect of the Phalanx. This results in a large enough proximally based flap of capsule with enough mobility to transfer into the joint space. The capsule after such preparation is seen dorsally and to the right of the Homans’ retractor in this image.

    With the 1 Vicryl suture already anchored into the plantar capsule an appropriate bite of the dorsal capsule(1) is taken .The objectives is good coverage of the metatarsal head with the transfer under appropriate tension .

    A v shaped wedge of capsule(1) is removed from the lower flap(2).This is in preparation for a corrective capsular closure.
    Note also how the dorsal capsular interposition(3) has been sewn into the MTP joint.

    The corrective capsular closure tightens the medial capsule and corrects any valgus deformity of the Hallux .
    The first stitch is placed plantar and proximal(1), the second dorsal and distal(2) and the final one plantar and distal(3) before tying off under appropriate tension.

    The main corrective capsular suture has been tied(1). A second simple suture has also been required for capsular tightening here(2).
    The K wire(3) has finally been driven across the MTP to hold the correction whilst soft tissue healing occurs.
    There will be excess medial skin and some capsule which can be excised at this stage to improve the immediate cosmetic appearance of the foot .

    Pre (left) and post(right) operative clinical pictures of a Kellers operation and associated second toe correction.

    Post Operative

    Day-case or overnight stay
    LMW Heparin 2 weeks
    Weight bear using post operative shoe for 5 weeks
    Crutches likely required 1-2 weeks
    Patient taught self-mobilisation of MTP from when K wire removed , at 5 weeks. Both active and passive mobilisations. A thera-band is useful for this . Comfort is more important than total range of movement. More emphasis should be placed on active plantar flexion given the not uncommon outcome of lack of Hallux ground contact post-operatively.
    Kellers bandage/post operative splint for 5 weeks
    Dressings to continue 24/7 until all wounds dry
    From 5 weeks the patients should cleanse the foot twice a day, once in a salt water bath and once by bathing/showering
    Dressings ,especially to medial wounds , to continue for the first month in shoe-wear.
    Appropriate shoe-wear fit is vital in the first month or so after post-op shoe
    I advise fit-flops , Uggs , wider fits or open sandals. Stiffer Heels ( platform or wedge ) are encouraged in women , from when comfortable , to promote MTP dorsi-flexion.

    Recommended Reading

    Outcomes following cheilectomy and interpositional arthroplasty in hallux rigidus.
    Foot & Ankle International.2001.22(6):462-470.
    J.T.C.Lau , T.R.Daniels.
    Mixed group but within it were 11 patients with severe arthritis treated with interpositional arthroplasty.
    Over 70% of patients were satisfied with the outcome. All however had pedobarograph demonstrated transfer issues.
    Only one failure to the extent fusion of the MTP was required during a 2 year follow up.
    Correction of Hallux Valgus: Metatarsal osteotomy versus excision arthroplasty.
    Clin Orthop Rel Res. 2000 Jul;(376):183-94.
    Zembsch A, Trnka HJ, Ritschi P.
    The 10-22 year results were compared in a group of 50 feet clinically following basal osteotomy against 37 feet following a Kellers operation for Hallux Valgus correction.
    Significantly better results were seen in the basal group though an almost 40% reported incidence of first metatarsal elevation post basal osteotomy seems very high and would account for the almost identical incidence of transfer metatarsalgia (just below 30%) seen in both groups.
    Interposition arthroplasty in the treatment of Hallux Rigidus.
    Acta Orthop Traumatol Turc. 2010; 44(2):143-51
    Ozan F, Bora OA, Filiz MA, Kemet Z.
    19 feet in a cohort of male and female patients aged from mid 50s to early 70s were operated on for severe Hallux Rigidus using a standard technique.
    Post-op patients rated their outcome excellent or good in 85% of cases . Post-operative movement through the first MTP had doubled from a pre-op value in the mid 2o degree range.
    Ground contact of the Hallux however was lost in 4/5ths of patients and 2/3rds had transfer metatarsalgia .

    Reference

    • orthoracle.com

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