DEFINITION

Deltoid ligament deficiency is present when both the deep and superficial components of the medial collateral ligament complex of the ankle are ruptured or are insufficient.

Deltoid ligament deficiency may result from degenerative (eg, late-stage adult acquired flatfoot deformity [AAFD]), postoperative,6,7,8 or traumatic or athletic4 causes.

 

 

ANATOMY

 

The deltoid ligament complex is a multiunit structure that provides support and restraint for the tibiotalar joint, subtalar joint, spring ligament, and talonavicular joint.

 

There is wide agreement that the deltoid ligament complex is made up of both deep and superficial components.

 

The deep portion of the complex originates from the intercollicular groove and posterior colliculus of the medial malleolus and inserts on the medial face of the talar body near the center of rotation of the tibiotalar joint.

These short and stout fibers are intra-articular but extrasynovial. It is made up of anterior and posterior fascicles.

 

There has not been agreement over the superficial components of the complex. In one of the more detailed

anatomic studies, Pankovich and Shivaram5 described the superficial layer as being made up of the tibionavicular, tibiocalcaneal, and tibiotalar ligaments. These fibers represent a triangular array originating on the distal medial malleolus and extending in a fan shape to their respective insertions. The relative contribution of these components to both ankle and foot biomechanics is still a topic of investigation.

 

PATHOGENESIS

 

The most common cause of deltoid ligament disruption is supination-external rotation (SER) ankle fractures. The most severe form of these fractures has either a medial malleolus fracture or a deltoid ligament rupture, in conjunction with a lateral malleolus fracture. The variant with an intact medial malleolus and disrupted medial collateral ligaments is termed SER IV-deltoid. This latter form is the most common form of deltoid ligament disruption.

 

It has been very well established that deltoid reconstruction is not indicated for disruptions that occur in conjunction with ankle fractures. Reduction and fixation of the fracture component with reestablishment of the mortise morphology leads to healing of the deltoid ligament in the vast majority of those with these combined

injuries.9

 

A smaller proportion of patients with deltoid ligament insufficiency will have developed this as a component of stage IV AAFD.2

 

Deltoid ligament insufficiency without concomitant ankle fractures resulting from the acute injury has been described but will not be discussed here. This chapter concentrates on deltoid ligament insufficiency arising from degenerative causes.

 

NATURAL HISTORY

 

As the posterior tibial tendon becomes deficient, the ability to bring the hindfoot into varus actively is lost.

 

As the mechanical axis of the leg is shifted medially (relative to the foot) and the hindfoot deformity becomes more severe and eventually stiff, tension is progressively increased on the soft tissues of the medial ankle. The medial collateral ligament complex becomes unable to resist the loads placed on it, with eventual

insufficiency and lengthening.7,8

 

Progression to stage IV AAFD occurs when the deltoid ligament becomes incompetent and the valgus force from the preexisting hindfoot deformity causes the talus to tilt within the mortise.

 

PATIENT HISTORY AND PHYSICAL FINDINGS

 

Aspects of the history and physical examination of stage IV AAFD will be similar to those found in the earlier stages of this AAFD.

 

There will be hindfoot valgus.

 

Because of the chronic nature of posterior tibial tendon involvement, strength will be greatly diminished and likely absent because of rupture. The patient will neither be able to resist hindfoot eversion nor actively bring the forefoot across midline.

 

Because of the decreased working length of the triceps surae resulting from chronic hindfoot valgus, there will be contracture of these muscles. A fixed hindfoot deformity may give a falsely optimistic impression of tibiotalar dorsiflexion. Reestablishment of ankle and hindfoot alignment without an appropriate lengthening of the heel cord will create or exacerbate an equinus deformity.

 

There may be significant forefoot supination.

 

Lateral pain may represent sinus tarsi or subfibular impingement, lateral ankle joint arthritis, or, in severe cases, distal fibular stress fracture.

 

Pain in the sinus tarsi is frequently unrecognized or underappreciated before palpation by the clinician.

 

Callosity and pain below the talar head may be present if substantial dorsolateral peritalar subluxation has caused a prominence in the medial plantar midfoot.

 

It is essential to determine whether the tibiotalar valgus deformity that is a hallmark of stage IV AAFD is rigid or reducible. This is further explained under Surgical Management.

 

 

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Clinical determination of the presence of valgus tibiotalar deformity is greatly enhanced with radiologic examination.

 

The integrity of the lateral collateral ligament complex needs to be determined. A severe valgus deformity may lead to erosion and incompetence of these structures.

 

The surgeon must also evaluate for the presence of ipsilateral knee valgus. If this is significant, consideration should be given to correcting the proximal deformity before the foot and ankle surgery. Correction of the leg-ankle-foot axis without attention to knee deformity may not adequately relieve valgus stress through the reconstructed lower limb and result in recurrence of deformity.

 

Methods for examining the deltoid ligament include the following:

 

 

Palpating the area inferior to the medial malleolus. Tenderness may represent incipient or recent deltoid rupture and may only be present early in stage IV disease.

 

Joint line palpation. The presence of valgus tilt indicates insufficiency of the deltoid ligament.

 

Weight-bearing anteroposterior (AP) ankle radiographs. Valgus tilt greater than 4 degrees indicates deltoid ligament insufficiency.

 

IMAGING AND OTHER DIAGNOSTIC STUDIES

 

The preferred radiologic views include the three-view weightbearing series. The AP standing view will provide the most information. Patients with deltoid ligament insufficiency will demonstrate tibiotalar valgus tilting (FIG 1).

 

Cross-sectional imaging is required only when plans are made for performing reconstruction using native peroneus longus tendon (discussed later). In this case, magnetic resonance imaging (MRI) is used to confirm the integrity of the peroneus brevis before the longus is harvested.

 

Selective intra-articular blocks often help the clinician localize the exact source of pain.

 

 

 

FIG 1 • Standing AP weight-bearing radiograph of the ankle demonstrating valgus tibiotalar tilt resulting from insufficiency of the deltoid complex.

 

DIFFERENTIAL DIAGNOSIS

Stage II or III AAFD

Medial malleolus fracture nonunion

Tibiotalar arthritis (with eccentric lateral joint erosion) Osteonecrosis of the talus with lateral collapse

Distal tibial supramalleolar valgus malalignment (resulting from distal tibiofibular fracture or pilon fracture) Valgus malunion of pronation-abduction-type ankle fracture with lateral plafond impaction or comminution

 

 

NONOPERATIVE MANAGEMENT

 

In contrast to acute deltoid deficiency presenting in conjunction with an ankle fracture, we believe that nonoperative care has a very limited place in patients with chronic deltoid ligament insufficiency resulting from degenerative causes (eg, stage IV AAFD). All but patients with medical comorbidities contraindicating surgery should undergo surgical reconstruction.

 

Conservative therapy may also be needed to relieve pain and temporize deformity while related orthopaedic conditions are corrected.

 

Should conservative therapy be chosen, custom-molded rigid orthotics that extend to the calf, such as the Arizona brace, provide the best chances of preventing progression of the disease.

 

Although halting the progression of the disease may be possible with conservative therapy, the deformities of stage IV cannot be corrected with bracing alone.

 

SURGICAL MANAGEMENT

 

Healing of a chronically insufficient deltoid ligament to a functional structure does not occur in AAFD. Reefing and other surgical techniques attempting to incorporate this diseased tissue into the repair do not produce reliable results. Allograft or autograft reconstructions of the deltoid ligament give the best chances for success.

 

Once a diagnosis of stage IV AAFD is made, an operative plan to correct all components of the deformity is needed.

 

Evaluation of the ability to passively correct the tibiotalar deformity is central to whether the deltoid ligament may be reconstructed for salvage of the ankle joint.

 

Tibiotalar valgus deformity that can be corrected passively may benefit from deltoid reconstruction in conjunction with bony and tendon work. Rigid tibiotalar deformity of stage IV AAFD should be reconstructed with tibiotalocalcaneal or pantalar fusion.

 

It is essential to correct all components of the foot deformity along with deltoid reconstruction so that the forces that resulted in the native deltoid ligament insufficiency are neutralized and do not cause failure of the reconstructed ligament.

 

If lateral collateral ligament insufficiency is found on examination, the surgical plan should include reconstruction of these structures.

 

Preoperative Planning

 

Imaging studies are reviewed.

 

Examination under anesthesia (EUA) should be accomplished before positioning the patient. Intraoperative fluoroscopy may be very useful during the EUA.

 

 

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It is also important to reevaluate the lateral collateral ligaments during the EUA.

 

All foot reconstructive procedures needed to restore plantigrade alignment should be done at the same surgical setting if possible. These procedures should be done immediately before deltoid ligament reconstruction.

 

Positioning

 

The patient should be positioned supine on the operating table.

 

Retrograde application of an Esmarch bandage followed by inflation of an upper thigh tourniquet may be used to create a relatively bloodless field.

 

Access to the medial ankle may be improved by placing a soft support under the contralateral hip.

 

The surgeon should ensure that the lower extremity is prepared and draped to a level above the knee so that limb-foot alignment may be evaluated intraoperatively.

 

Approach

 

The approach for the minimally invasive deltoid ligament reconstruction (MIDLR) requires a longitudinal incision from the tip of the medial malleolus to just inferior to the prominence of the sustentaculum tali. This incision may need to be carried through incompetent fibers of the superficial deltoid ligament (FIG 2).

 

 

 

 

FIG 2 • Approach for the minimally invasive deltoid ligament reconstruction technique marked out on the medial ankle. The locations of the medial malleolus, talus, and sustentaculum tali are indicated.

 

 

The approach for the peroneal grafting method uses a straight longitudinal incision over the peroneal tendons to harvest the peroneus longus tendon and then a medial incision through which the tendon is brought before threading it through and securing it to the tibia. The patient should be initially positioned with a bump under the ipsilateral hip, which may be removed when increased access to the medial ankle is required.

 

TECHNIQUES

• Minimally Invasive Deltoid Ligament Reconstruction

This technique1,2 reconstructs components of both the superficial and deep layers of the deltoid ligament without sacrificing any host tissue for graft.

 

Forked Allograft Preparation

 

Cadaveric allograft from the posterior tibial tendon or the peroneal tendon provides a graft of good size. Larger grafts (eg, Achilles tendon) may be used but should be cut to appropriate thickness. Do not use grafts smaller than the posterior tibial tendon or peroneals.

 

The graft should be about 20 cm in length and 6 to 7 mm in diameter. Split one end longitudinally, leaving about 5 cm of the opposite end unsplit.

 

Place Krackow stitches of no. 0 nonabsorbable woven suture in all three limbs of the tendon (TECH FIG 1).

 

After preparation, wrap the graft in moistened gauze and set it aside.

Tibial Limb Placement

 

Above the medial malleolus, in the midcoronal plane, choose a level about 1 cm above the plafond at which the tibial limb of the graft will be anchored. This is approximated well by the level of the distal tibial physeal scar. Intraoperative fluoroscopy is very helpful in locating a proper site. The saphenous vein and nerve should be anterior to the entry site chosen.

 

At the level of insertion, make a 1-cm longitudinal incision down to medial tibial cortex. Advance a guidewire from medial to lateral parallel to the plafond (TECH FIG 2). Make a 6.0-mm blind tunnel over the guidewire for a distance of 25 mm. Remove the guidewire.

 

 

 

TECH FIG 1 • Preparation of forked graft. An allograft tendon about 20 cm long and 7 mm in diameter is chosen and split longitudinally for about two-thirds of its length. Final appearance of the forked graft, showing Krackow sutures placed in all three ends of its limbs.

 

 

Secure the tibial limb (unsplit end) of the forked graft in the blind tibial tunnel using a 6.25-mm soft tissue interference screw (TECH FIG 3). Use manual testing to ensure that the graft is adequately anchored in the tunnel.

Talar Limb Placement

 

The path of the tunnel through the talus starts at the medial center of tibiotalar rotation. This is most easily approximated by drilling the insertion point for the native deep deltoid ligament. The lateral

 

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exit of the tunnel is located at the lateral junction of the talar dome and neck. This lateral exit point is located by palpation. If this junction cannot be palpated, a small incision may need to be made to locate the lateral neck-body junction. Advance a guidewire for a cannulated 5.0-mm drill along this axis. Confirm the position of the guidewire with AP and lateral fluoroscopic views.

 

 

 

TECH FIG 2 • Insertion of tibial limb. A. Starting point for tibial guidewire placement should be at the level of the distal tibial physeal scar. B. Tibial guidewire placement as shown by AP view with fluoroscopy. C. Securing the tibial limb of the graft with a soft tissue interference screw.

 

 

Drill a 5.0-mm tunnel over the guidewire. Pass one end of the sutured tendon through the tunnel from medial to lateral using a suture passer. Place appropriate tension on the graft and place a 5.0-mm soft tissue interference screw in the medial aspect of the tunnel to secure the graft. Advance the interference screw so that it is countersunk 1 to 2 mm into the tunnel.

 

 

 

TECH FIG 3 • Talar limb placement. A. Starting point for the talar tunnel is approximated by the footprint of the deep deltoid ligament insertion on the medial face of the talus. Shown is the medial talar surface of a cadaveric dissection specimen. A soft tissue interference screw has been placed in the medial portion of the talar tunnel. The talar head is oriented to the right in this image. B. Path of the talar tunnel as seen from a dorsoplantar view of a cadaveric talus. The talar head is toward the bottom and the medial talus is at the left side of the image. The lines represent the path of the tunnel through the talus. C. Medial aspect of ankle after talar limb has been inserted, tensioned, and secured.

Calcaneal Limb Placement

 

Using palpation, locate the medial border of the sustentaculum tali. Once it is found, carefully dissect the posterior tibial tendon sheath away from the bone and retract it inferiorly. Insert the guidewire to the cannulated drill along an axis from the midportion of the sustentaculum tali to a point about 1 cm superior to the peroneal tubercle on the lateral side of the calcaneus (TECH FIG 4A). Placing the guidewire in this location allows for centralization in the sustentaculum and minimizes the chances of breaching the subtalar joint. Check the position of the guidewire using fluoroscopy.

 

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Create a 5.0-mm tunnel over this guidewire.

 

Pass the free end of the remaining limb of the tendon graft through the sustentacular tunnel and out the skin overlying the lateral calcaneus. A small slit may need to be made to allow the graft to be pulled fully through. Perform tensioning and tibiotalar joint position manually and check it under fluoroscopy.

 

 

 

TECH FIG 4 • Calcaneal limb placement. A. Starting point for the calcaneal limb with guidewire advanced so as to avoid the subtalar joint and exit out the lateral calcaneal cortex. B. Completed minimally invasive deltoid ligament reconstruction in situ from the medial aspect. C. Completed minimally invasive deltoid ligament reconstruction from the medial aspect and from a posteroanterior view.

 

 

When appropriate tension is achieved, insert a 5.0-mm interference screw from medial to lateral into the sustentacular tunnel.

 

The appearance of the final construct in situ is illustrated in TECH FIG 4B. An illustration of the position of the graft after insertion and fixation is shown in TECH FIG 4C.

 

Close the wounds in a layered fashion.

• Peroneus Longus Graft Tendon Harvesting

 

Harvest the peroneus longus tendon through a lateral incision that extends from the fourth metatarsal base to about midway up the calf.3

 

Tenodese the proximal stump of the transected peroneus longus tendon to the peroneus brevis.

 

After securing a Krackow locking suture to the free end of the peroneus longus tendon, wrap it in a piece of moist gauze.

Talar Tunnel Construction

 

Make a medial incision centered over the medial malleolus, extending distally over the fibers of the superficial deltoid.

 

Divide the fibers of the attenuated deltoid ligament, exposing the medial aspect of the talus.

 

Pass an intraosseous guidewire from the lateral talar neck-body junction to the estimated center of rotation on the medial aspect of the talus inferior to the tip of the medial malleolus.

 

Verify guidewire position fluoroscopically and clinically by dorsiflexing and plantarflexing the ankle to determine if the center of rotation has been localized.

 

Create a tunnel using a cannulated reamer about 4 to 5 mm in diameter.

Tibial Tunnel Construction

 

Create a second bony tunnel from the tip of the medial malleolus to a point in the lateral distal tibia. The exit point is about 5 to

 

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6 cm proximal to the tibial plafond and anterior to the fibula. We recommend saving the shavings from the reamer to be used later as bone graft.

Graft Passage and Fixation

 

Pass the tendon through the tibial tunnel from distal medial to proximal lateral.

 

 

 

TECH FIG 5 • Peroneus longus autograft construct. Completed peroneus longus autograft has been passed through the talar tunnel, into the medial malleolus, and out the lateral tibia, where it is fixed to the lateral cortex.

 

 

Tension the tendon first at the medial talar tunnel and then at the lateral tibial exit site, with correction of valgus talar tilt.

 

Secure the tendon to the lateral tibia under maximal tension with a soft tissue washer or staple. Pack bone graft obtained from reaming in the bony tunnels. A schematic of the final construct is depicted in TECH FIG 5.

 

Close the wounds.

 

PEARLS AND PITFALLS

 

Need for concomitant procedures

• Deltoid reconstruction as described here is intended to reconstitute a functional restraint to valgus tibiotalar tilting.

• Be sure to correct any malalignment or deformity that will tend to produce valgus angulation at the tibiotalar joint at the same time that the deltoid reconstruction is done.

• Failure to do this may result in the correction being inadequate or may even lead to outright failure of the graft.

   

  Fixation problems: graft pullout

• Ensure that the tendon ends are reinforced with Krackow sutures to allow for secure passage of the tendons and to prevent interference screw laceration of the graft.

   

  Tunnel placement

  • Make sure the talar tunnel starts medially at the insertion of the deep deltoid ligament. Substantial deviation of the starting point of the talar tunnel from this location will result in increased shearing forces across the tendon.

  • The superficial (calcaneal) limb of the graft must be centered within the sustentaculum. Eccentric placement may result in the medial facet of the subtalar joint or the inferior cortex of the sustentaculum being breached. Breaching the medial facet could lead to subtalar arthritis. Breaching the inferior sustentacular cortex could result in flexor hallucis longus paratenonitis or abrasion.

 

Nerve injury ▪ Make small incisions over the exit of the talar and calcaneal limbs to prevent damage to branches of the superficial peroneal and sural nerves.

 

Indications ▪ These techniques are designed to aid in the surgical correction of stage IV AAFD. Other treatment methods may need to be used for either acute deltoid injuries or deltoid insufficiency associated with disease processes other than AAFD.

 

POSTOPERATIVE CARE

 

In the immediate period after tibiotalar joint-sparing reconstruction of stage IV posterior tibial tendon rupture, a plaster splint is applied in neutral position. Physiotherapy starts after the incisions have healed, usually about 2 weeks postoperatively. Therapy consists of passive and active mobilization of the ankle joint as well as intrinsic muscle exercises. Weight bearing is started progressively but is not full until 12 weeks postoperatively. Gait training is instituted as needed after weight bearing is commenced.

 

 

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OUTCOMES

There are no long-term results for these methods because both were recently developed. Studies on outcomes are made difficult by the small number of patients who present with stage IV AAFD. Ongoing studies are evaluating the ability to maintain the correction and stability obtained with these methods.

Two-year clinical results for the forked graft method are just becoming available at the time of the writing of this chapter. Initial short-term results are promising, with maintenance of tibiotalar joint motion and stability in those who have undergone the procedure.

Short-term follow-up data are available for the peroneus longus graft method. In the five patients

 

evaluated after undergoing this procedure, four had tibiotalar valgus correction to 4 degrees or less that was maintained 2 years after the procedure.

 

 

COMPLICATIONS

Breaching tibiotalar joint with misplaced tibial or talar tunnel

Breaching subtalar joint with misplaced calcaneal tunnel (forked graft method) Damage to superficial peroneal nerve

Damage to deep peroneal nerve (peroneal graft method)

Damage to the sural nerve on calcaneal limb pull-through (forked graft method) Infection

Graft failure or rupture

 

 

REFERENCES

1. Bluman EM, Khazen G, Haraguchi N, et al. Minimally invasive deltoid ligament reconstruction: a biomechanical and anatomic analysis. Presented at American Orthopaedic Foot and Ankle Society 21st Annual Summer Meeting, Boston, MA, 2005.

    

    

2. Bluman E, Myerson M. Stage IV posterior tibial tendon rupture. Foot Ankle Clin 2007;12:341-362.

    

    

3. Deland JT, de Asla RJ, Segal A. Reconstruction of the chronically failed deltoid ligament: a new technique. Foot Ankle Int 2004;25: 795-799.

    

    

4. Hintermann B, Valderrabano V, Boss A, et al. Medial ankle instability: an exploratory, prospective study of fifty-two cases. Am J Sports Med 2004;32:183-190.

    

    

5. Pankovich AM, Shivaram MS. Anatomical basis of variability in injuries of the medial malleolus and the deltoid ligament. I. Anatomical studies. Acta Orthop Scand 1979;50:217-223.

    

    

6. Pell RF IV, Myerson MS, Schon LC. Clinical outcome after primary triple arthrodesis. J Bone Joint Surg Am 2000;82(1):47-57.

    

    

7. Resnick RB, Jahss MH, Choueka J, et al. Deltoid ligament forces after tibialis posterior tendon rupture: effects of triple arthrodesis and calcaneal displacement osteotomies. Foot Ankle Int 1995; 16:14-20.

    

    

8. Song SJ, Lee S, O'Malley MJ, et al. Deltoid ligament strain after correction of acquired flatfoot deformity by triple arthrodesis. Foot Ankle Int 2000;21:573-577.

    

    

9. Zeegers AV, van der Werken C. Rupture of the deltoid ligament in ankle fractures: should it be repaired? Injury 1989;20:39-41.