DEFINITION

Spring ligament failure consists of lengthening or disruption of the spring ligament complex resulting in subluxation at the talonavicular joint.

Spring ligament failure is commonly associated with considerable degeneration of the ligament. The ligament complex may have tears or large defects, or it may just be attenuated.

Tears most commonly occur in the superomedial portion of the spring ligament complex, adjacent to the posterior tibial tendon, but can occur in the inferior portion as well.

It is necessary to look at the alignment of the foot to determine how to treat failure in the spring ligament. If a flatfoot is present with increased heel valgus or abduction (or both) through the midfoot and there is a full tear of more than 30% of the ligament or severe attenuation, the risk of progression of deformity is high.

 

 

ANATOMY

 

The spring ligament is actually a complex of ligaments composed primarily of a superomedial portion and an inferior portion. The deltoid ligament blends in with the superomedial portion.1

 

 

 

FIG 1 • A. Anatomy of the spring ligament complex (dorsal view with talar head removed). Note the location of the superomedial and inferomedial positions. The superomedial portion is medial to the posterior tibial tendon. It originates from the superomedial aspect of the sustentaculum tali and anterior facet of the calcaneus to insert on the medial navicular adjacent to its articular surface. B. Anatomy of the spring ligament complex seen from the plantar view. The inferior portion originates from the notch between the anterior and medial calcaneal facets. It inserts on the inferior surface of the midnavicular, just lateral to the insertion of the superomedial portion of the spring ligament.

 

 

The superomedial portion is medial to the posterior tibial tendon. It originates from the superomedial aspect of

the sustentaculum tali and the anterior facet of the calcaneus to insert on the medial navicular adjacent to its articular surface (FIG 1A).

 

The inferior portion originates from the notch between the anterior and medial calcaneal facets. It inserts on the inferior surface of the midnavicular, just lateral to the insertion of the superomedial portion of the spring ligament (FIG 1B).

 

Because of location, failure of the superomedial portion results in primarily medial migration of the talar head, whereas that of the inferior portion results in primarily plantar migration. Most commonly, the migration is both medial and plantar (FIG 2).

 

PATHOGENESIS

 

Spring ligament failure is usually due to the repetitive stresses of a flatfoot causing increased strain on the medial ligaments of the foot.

 

Failure most often occurs in the setting of a degenerated ligament, but it can be associated with an acute episode.

 

Although spring ligament failure is associated with a preexisting flatfoot, once spring ligament failure occurs, it frequently

 

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results in progressive deformity of the foot at the talonavicular joint and hindfoot. Because the foot progresses out from under the talar head dorsally and laterally, the talar head migrates medially and plantarly in relation to the rest of the foot.

 

 

 

FIG 2 • Because of its location, failure of the superomedial portion should result in primarily medial migration of the talar head, whereas failure of the inferior portion results in primarily plantar migration. Most commonly, the migration is both medial and plantar. A. MRI scan with severe degeneration and attenuation (grade III/IV) of the superomedial portion of the spring ligament complex. B. MRI with a severely frayed and degenerated (grade IV/IV) plantar portion of the spring ligament complex.

 

NATURAL HISTORY

 

 

Failure of the spring ligament complex most commonly occurs along with posterior tibial tendon insufficiency.3 With or without tendon insufficiency, spring ligament failure places the patient at risk for progressive subluxation at the talonavicular joint. If subluxation is already present, progression of the subluxation is highly likely.4

 

Progressive subluxation at the talonavicular joint eventually can cause enough deformity in the triple joint complex (ie, the talonavicular, calcaneocuboid, and subtalar joints) to result in lateral impingement and pain in the hindfoot, a collapsed foot.

PATIENT HISTORY AND PHYSICAL EXAMINATION

 

Patients present with medial pain, which usually is associated with the failure of the posterior tibial tendon rather than the spring ligament. Isolated traumatic injuries to the spring ligament do occur but are uncommon. Later in the course of the condition, if enough deformity has occurred, pain occurs in the lateral hindfoot from impingement secondary to subluxation in the triple joint complex.

 

Depending on the presence and amount of deformity, the patient may or may not notice the weakness or collapse in the arch. Most patients notice some weakness.

 

Physical examination should evaluate the posterior tibial tendon and alignment of the foot with the patient letting the arch sag fully when standing.

 

The posterior tibial tendon should be palpated for tenderness. Inversion strength should be tested from an everted position to a plantarflexed and inverted position.

 

Clinical alignment should be checked for midfoot abduction and height of the arch as noted on the frontal standing view. The degree of heel valgus is assessed from the posterior standing view.

 

Physical examination should also include the following steps:

 

 

Palpate the medial talonavicular joint and posterior tibial tendon to check any tenderness.

 

Tenderness on the tendon indicates tendon involvement and often masks tenderness from a ligament tear.

 

Evaluate range of motion. Compare the arc of motion (maximum eversion to maximum inversion) to the other foot. The arc of motion may be categorized as follows: full, some inversion present, motion only to neutral, or joint contracted in eversion. The joint must be mobile into inversion for tendon repair or reconstruction.

 

Evaluate inversion strength. Start with the foot in eversion and have the patient push against the examiner's hand to inversion and plantarflexion. Do not be misled by combined dorsiflexion and inversion strength, which is from the anterior tibial tendon and muscle.

 

IMAGING

 

The anteroposterior (AP) and lateral foot radiographs should be obtained standing with the patient told to let the arch sag. An AP standing radiograph of the ankle also should be performed to rule out valgus deformity at the ankle joint.

 

 

On the AP view of the foot, abduction at the talonavicular joint can be measured with the talonavicular uncoverage angle (ie, the amount of talar head not covered by the navicular; FIG 3A).

 

On the lateral view, plantar migration of the talar head in relation to the navicular can be checked (FIG 3B). The lateral talometatarsal angle, although a useful measurement, includes deformity at the naviculocuneiform and metatarsal-tarsal joints.

 

Radiographs are not diagnostic tools but are helpful in assessing deformity—as long as the patient is standing, letting the arch sag with weight bearing.

 

A magnetic resonance imaging (MRI) scan visualizing the spring ligament complex of the ligament tear and amount of degeneration can indicate the amount of degeneration or tear in the complex and is useful for diagnosis if it is of good quality and if it is read by an experienced examiner (see FIG 2).

 

DIFFERENTIAL DIAGNOSIS

Degeneration or tear of the posterior tibial tendon without spring ligament failure

 

Congenital flatfoot

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FIG 3 • The lateral and AP radiographic views of the foot should be obtained with the patient standing and told to let the arch sag. A. Standing lateral view of the foot showing a flat medial longitudinal arch with an increased talometatarsal angle on the lateral view. B. The AP view shows increased uncoverage of the medial talar head. These findings are characteristic—but not diagnostic—of a flatfoot associated with spring ligament pathology. Standing AP radiograph of the ankle also should be performed to rule out valgus deformity at the ankle joint.

 

 

 

 

NONOPERATIVE MANAGEMENT

 

Nonoperative management is particularly appropriate for those patients for whom the tear and alignment are thought to have a low probability of progression. These are patients with no or minimal flatfoot deformity and not a large tear. Conservative treatment may also be used for those patients who wish to delay surgery, but they must be informed of the risk of progression of deformity.

 

Nonoperative management consists of support for the medial longitudinal arch with one of the following devices. (They do not at all guarantee stopping the progression of deformity.)

 

 

A removable boot is helpful for initial management. A medial longitudinal arch support inside the boot is advised.

 

A short, articulated ankle-foot orthosis is less cumbersome and allows ankle motion with a customized arch support.

 

A custom orthotic with a medial longitudinal arch support and medial heel wedge is the least cumbersome but also provides the least support.

 

A solid leather gauntlet or Arizona brace allows minimal motion. It is best for those patients with considerable deformity and limited function.

 

Patients receiving conservative care should be monitored for progression of flatfoot deformity.

 

SURGICAL MANAGEMENT

 

Surgery is the best choice for patients with progression of flatfoot deformity associated with failure of the spring ligament complex or patients whose alignment places them at high risk for progressive deformity.4

 

Relative contraindications include medical conditions that adversely affect healing such as diabetes, corticosteroid use, and neuropathy.

 

Reconstruction of the spring ligament is not useful in those patients with rigid hindfoot deformity and is not necessary in those patients with small tears or good correction of alignment with bony procedures.

 

Preoperative Planning

 

Standing clinical alignment and standing AP and lateral radiographs of the foot and ankle should be carefully reviewed to plan for correction of alignment as well as repair or reconstruction of the spring ligament. A heel alignment (Saltzman view) is also helpful to assess amount of calcaneal valgus.

 

Surgeons should be prepared to deal with large tears or significant tissue loss in the spring ligament complex.

 

 

 

This will often necessitate the use of tendon graft, most commonly allograft tendon. Possible Achilles contracture should be assessed.

 

Correction of the foot alignment should be considered a critical part of the procedure.

 

Remember that repair or reconstruction of the spring ligament on its own has yet to be shown to correct bony malalignment and that a flatfoot deformity places strain on the spring complex.

 

Alignment correction is achieved by spring ligament reconstruction if osteotomies are performed at the same time and the foot is placed near the corrected position (>50% corrected) by the osteotomies. Although spring ligament reconstruction cannot give correction on its own, it can add correction to what is achieved by the bony procedures.

 

Spring ligament reconstruction is the most logical choice for large tears and is performed along with bony realignment of deformity.2,5,6

Positioning

 

The patient is placed in the supine position with a bolster under the greater trochanter so that the lower leg is neither internally or externally rotated. This allows good access to both sides of the foot.

 

In this position, exposure of the spring ligament, posterior tibial tendon, and lateral hindfoot is possible.

 

Approach

 

A medial incision is made from the tip of the medial malleolus to 2 cm distal to the navicular to inspect the posterior tibial tendon and expose the spring ligament complex by retracting the tendon.

 

Lateral hindfoot incisions are used as necessary for calcaneal osteotomies.

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TECHNIQUES

• Primary Superomedial Spring Ligament Repair

Primary repair rather than reconstruction is done when good tissue for repair is present and ends can be

 

well apposed. Foot deformity is corrected at the same time by the bony procedures.

 

Figure-8 or horizontal mattress sutures are placed to appose both ends of the ligament with the foot in neutral position. Knots are placed to avoid impingement against the posterior tibial tendon (TECH FIG 1).

 

If the ligament cannot be apposed with the foot in neutral or the tissue is attenuated, then reconstruction of the ligament is necessary for large tears. The reconstruction is performed together with osteotomies to correct bony alignment.

 

 

 

TECH FIG 1 • Operative photograph of repair of spring ligament. This repair was accompanied by a medial slide calcaneal osteotomy to address the deformity. Figure-8 or horizontal mattress sutures are placed to appose both ends with the foot in neutral position. Knots are placed to avoid impingement against the posterior tibial tendon.

• Superomedial Spring Ligament Reconstruction

   

  Tendon graft is used to replace insufficient ligament tissue and block medial migration of the talar head.

   

  Achilles or peroneus longus allograft is used most commonly, although peroneus longus autograft can be used if both the longus and brevis are in good condition and overcorrection of bony realignment is avoided.

   

  Because the superomedial spring ligament blends in with the anterior deltoid ligament, which also can be attenuated, reconstruction of the anterior deltoid and superomedial spring ligaments is commonly performed together (TECH FIG 2A).

   

  Bone tunnels in the navicular and tibia are used to create a ligament path to support the medial talar head (TECH FIG 2B).

   

  The navicular tunnel is placed from dorsal to plantar/medial over a cannulated drill. The graft is to exit plantar medially and cross the medial talar head.

   

   

   

  TECH FIG 2 • A. Diagram of superomedial spring ligament reconstruction. The repaired ligament crosses the medial aspect of the talar head to block medial migration of the head. B. Exit hole of the graft at the inferior navicular and corresponding entrance hole into the tibia at the midportion of the tip of the medial malleolus. The navicular hole is drilled from dorsal to plantar and the tibial hole from the medial malleolus up through the medial tibial metaphysis above the ankle. Bone tunnels in the navicular and tibia are used to create a ligament path to support the medial talar head. Screw placement is not chosen until the graft is tensioned. An alternative to the tibial drill hole is a drill hole to the medial calcaneus at the sustentaculum to fixate the graft at that location after it has passed through the navicular drill hole and then along both the medial and more plantar aspect of the talar head.

   

   

  A tibial tunnel beginning at the most inferior midportion of the medial malleolus tip is used.

   

  The tibial tunnel exits medially 5 to 9 cm above the ankle joint line.

   

  A medial longitudinal incision over the tibia is used to access the medial tibia for drilling of the tunnel.

   

  Given the size of the foot, the largest drill hole in the navicular is used, so a large tendon graft (6 to 8 mm) is possible.

   

  The graft is fixed at the navicular first and tensioned at the proximal exit of the tibial drill hole. The graft is tightened with the talonavicular joint in neutral to slight adduction.

   

  Fixation of the graft is with whipstitch using no. 2 nonabsorbable suture tied at each end and tied to a dorsal screw in the navicular and a medial screw on the tibial shaft.

   

  With the navicular end tied down first, the foot is placed in neutral to slight adduction and the ligament graft tensioned. The screw's position is then chosen such that the graft can be properly tensioned.

  Tension the graft,

   

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  place the screw, and then tie down the graft and place the bone graft in the tunnels.

   

  Alternative fixation is interference screws at the distal tibia, but the fixation may not be as strong with this technique. Placing an interference screw on the navicular risks fracture.

   

  Spring ligament reconstruction alone cannot be expected to hold correction and should, based on my experience, be used as a supplement to a lateral column lengthening procedure.

   

  Lateral column lengthening is done to place the talonavicular joint in neutral alignment.

   

  The lateral column lengthening procedure should allow a minimum of 5 degrees of passive eversion to avoid excessive lateral tightness and adequate eversion motion remaining should be in the operating room by everting the foot.

• Inferior Spring Ligament Reconstruction

   

  Tendon grafting also is used but for deformity that is primarily plantar migration of the talar head.

   

  Graft is used to replace attenuated or degenerated tissue in combination with bony procedures to correct flatfoot deformity (TECH FIG 3A).

   

  Bone tunnels are used in the navicular and calcaneus (TECH FIG 3B).

   

  The navicular tunnel is made from dorsal to plantar medial.

   

  The calcaneal tunnel is drilled from just underneath the sustentaculum tali and exits out the lateral calcaneus. The lateral exit point is exposed using the standard oblique incision for a posterior calcaneal osteotomy.

   

   

   

  TECH FIG 3 • A. Diagram of plantar spring ligament reconstruction with the graft extending from the drill hole in the navicular to the calcaneus. B. Navicular exit hole and calcaneal entrance for the graft. A drill hole is made dorsal (dorsal portion not shown) to plantar in the navicular and medial to lateral (not shown) in the calcaneus.

   

   

  The graft is fixed first at the navicular, with the foot placed in 5 degrees of inversion with the calcaneus out of valgus (neutral). A medializing calcaneal osteotomy is commonly performed to address valgus deformity and is fixed before the calcaneal drill hole is made.

   

  The graft is pulled through the calcaneal tunnel and tensioned with the talus out its plantarflexed position (“slight dorsiflexion”). Temporary pinning of the talonavicular joint can be done in the position described, and the graft is then tensioned and fixed. Fixation of the graft is with nonabsorbable suture sewn into the ends of the graft and tied down to screws in the dorsal navicular and lateral calcaneus. Alternative or supplemental fixation is done with interference screws.

   

  The calcaneus cannot be left in valgus or excessive strain on the graft will result.

• Combined Superomedial and Plantar Spring Ligament Reconstruction

 

Combined superomedial and plantar spring ligament reconstruction is done for patients with considerable abduction of the talonavicular joint and plantar migration of the head.

 

Two tendon grafts or a large tendon graft that is split at the plantar medial navicular tunnel is used (TECH FIG 4B,C).

 

The navicular tunnel is made as large as possible without fracturing the navicular to enable placement of large grafts. If allograft tendon is used, Achilles allograft with a bone block in the navicular tunnel is suggested (TECH FIG 4D).

 

The talonavicular joint is pinned in the corrected position (ie, 5 degrees of inversion and the calcaneus in neutral) after any bony procedures are fixed.

 

Depending on the technique, the graft is fixed first at the navicular (split technique) or passed from the first metatarsal

 

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to the calcaneus. Once the free ends are passed into the tibia or calcaneus, the final fixation to screw posts is done after tensioning the graft to the screw in the tibia or at the navicular. At the calcaneus, interference screws can be used.

 

 

 

TECH FIG 4 • A. Diagram of combined spring ligament complex reconstruction shows combined superomedial and plantar reconstruction. Two tendon grafts or a single large tendon graft that is split at the plantar medial navicular tunnel are used. B,C. Diagrams of alternative combined spring ligament reconstruction using the peroneus longus left attached to first metatarsal base (shown) or free graft from the navicular plantar hole to the calcaneus and back to the navicular dorsal hole (not shown). Two tendon grafts or a large tendon graft that is split at the plantar medial navicular tunnel are used. D. Drill holes for the combined spring ligament complex reconstruction with the graft exiting the plantar navicular and going into drill holes at the calcaneus. The navicular tunnel is as large as possible without fracturing the navicular to enable placement of large grafts. If allograft tendon is used, Achilles allograft with a bone block in the navicular tunnel is suggested.

 

 

Reconstruction with combined techniques is intended not to replace bony procedures but to supplement them when considerable tissue loss in the spring ligament complex is noted and correction of bony alignment has been gained at or near neutral position.

PEARLS AND PITFALLS

Do not expect soft ▪ The foot must be well aligned without excessive calcaneal valgus (≤5

tissue reconstruction to degrees) and without excessive abduction through the talonavicular joint correct bony (<40% uncoverage).

malalignment.

Avoid over- and

undercorrection of deformity.

• Correct bony malalignment first. Then, pin or hold the talonavicular joint

in neutral position before tensioning the reconstruction.

Do not use lateral

column lengthening unless necessary.

• Bony procedures, although necessary to correct malalignment, have

morbidity. For lateral column lengthening, good eversion motion should remain after the bony procedures and fixing the tendon grafts.

Avoid weakening of

tendon grafts.

• Fix bony procedures first to avoid crossing bony tunnels with screws,

and use sizers to avoid multiple passages of the tendon grafts in tunnels.

Avoid unnecessary

spring ligament reconstruction.

• Small tears and mild to moderate deformity do not necessitate spring

ligament reconstruction.

Commonly, a posterior osteotomy and lateral column lengthening are performed.

 

 

 

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POSTOPERATIVE CARE

 

 

Touchdown weight bearing is allowed at 2 weeks and progressive weight bearing from 8 to 10 weeks. In reliable patients, a cast boot can be used instead of a cast beginning at 4 weeks.

 

Full weight bearing without a boot is allowed at 12 to 16 weeks.

 

Active inversion and eversion can be started at 6 weeks.

OUTCOMES

Because spring ligament reconstructions are commonly combined with other procedures, it is difficult to define the contribution of these procedures to patient outcomes, and no reports have done so until recently.

In our experience, spring ligament reconstruction does contribute to correction of deformity but only when most of the correction has been achieved through the bony procedures. I would use the superomedial spring ligament reconstruction for those feet with more of an abduction deformity and the plantar for those with more of a plantar sag deformity at the talonavicular joint. The superomedial may adequately correct combined deformity; if not, use the combined superomedial and spring ligament reconstruction.

 

 

 

 

COMPLICATIONS

Failure of the graft can occur, particularly when a soft tissue procedure is used to try to correct large amounts of deformity without adequate bony correction of deformity.

Failure of fixation of the graft. Interference screws are helpful, but the fit must be tight and tunnels must be made at somewhat of an angle to avoid straight pullout of the graft. Large grafts combined with interference screws are not recommended because of the risk of fracture.

Overcorrection with lateral weight bearing can occur, either with a medial slide osteotomy or, more commonly, if lateral column lengthening is used. Normal eversion motion should be maintained.

The heel should be in alignment with the lower leg ( clinically straight), and passive eversion into at least 5 degrees should be present after all the procedures are fixed.

The lateral column should not feel tight on range-of-motion testing in the operating room after the bony correction; eversion should be present.

 

 

REFERENCES

1. Davis WH, Sobel M, Deland JT, et al. Gross, histological and microvascular anatomy and biomechanical testing of the spring ligament complex. Foot Ankle Int 1996;17:95-102.

    

    

2. Deland JT. The adult acquired flatfoot and spring ligament complex. Pathology and implications for treatment. Foot Ankle Clin 2001;6:129-135.

    

    

3. Deland JT, de Asla RJ, Sung IH, et al. Posterior tibial tendon insufficiency: which ligaments are involved? Foot Ankle Int 2005;26:427-435.

    

    

4. Deland JT, Page A, O'Malley MJ, et al. Posterior tibial tendon insufficiency results at different stages. HSS J 2006;2:157-160.

    

    

5. Hiller L, Pinney S. Surgical treatment of acquired adult flatfoot deformity: what is the state of practice among academic foot and ankle surgeons in 2002? Foot Ankle Int 2003;24:701-705.

    

    

6. Pinney SJ, Lin SS. Current concept review: acquired adult flatfoot deformity. Foot Ankle Int 2006;27:66-75.