Reconstructing The Deltoid Ligament In A Case Involving Total Ankle Replacement

In the setting of a total ankle replacement, these authors present a novel technique of ligament repair in a patient with a significant medial deltoid insufficiency associated with stage IV posterior tibial tendon dysfunction.

Ankle osteoarthritis (OA) is often associated with deformities. Valgus OA is less frequent than varus OA and causes of valgus OA include medial ligament instability, flatfoot and posttraumatic situations (e.g. fractures of the fibula or lateral tibial plafond). The importance of the mechanical axis is mandatory in order for a total ankle replacement to maintain alignment and success. In cases involving total ankle replacements, one must restore the normal biomechanics in order to have a correct and pain-free functioning total ankle replacement both in the short and long-term. An anterior tibiotalar angle of about 90° in the sagittal plane and a neutral hindfoot and ankle position in the frontal plane are necessary to maintain alignment and success.

One of the biggest challenges for surgeons performing total ankle replacement surgery is the medial deltoid insufficiency associated with stage IV posterior tibial dysfunction.  

Myerson described the fourth stage of posterior tibial tendon dysfunction when the talus tilts into valgus within the ankle mortise secondary to deltoid insufficiency. Stage IV is further broken down into IV-A flexible ankle valgus without substantial tibiotalar arthritis and stage IV-B rigid or flexible valgus with significant tibiotalar arthritis.^1,2 It is paramount to determine which of these two subclassifications a patient falls into because one would generally perform an ankle joint-sparing procedure for stage IV-A posterior tibial tendon dysfunction whereas the surgeon would use a joint-sacrificing procedure for stage IV-B.

Valgus deformity occurs in approximately 8 percent of arthritic ankles.³ In cases of advanced adult-acquired flatfoot (AAF) deformity, the spring ligament complex often attenuates or ruptures. Failure of this ligament complex allows the talar head to shift medial and plantar relative to the navicular. As the deltoid ligament complex fails, the talus may assume a valgus position within the ankle mortise. The deltoid ligament complex consists of superficial and deep components. It has significant contribution to the spring ligament, tibiotalar joint, subtalar joint and talonavicular joint.^4-7 Sectioning of the deltoid ligament complex has demonstrated that both the superficial and deep components prevent tibiotalar tilt.

When taking radiographs, contralateral views are helpful in evaluating ligamentous laxity versus true deltoid disruption. Concomitant varus deformity may also be present with lateral ligament insufficiency and one should evaluate this dynamically with fluoroscopy. Cadaveric studies reveal that when a surgeon releases the deep and superficial components of the deltoid ligament complex is a significant amount of valgus talar tilt may occur.^8-10 This can also decrease the ankle joint contact area by up to 43 percent.⁹

This valgus angulation creates uneven pressure distribution causing increase in lateral loading of the tibiotalar joint that eventually leads to an arthritic ankle.¹⁸ If one must also perform flatfoot realignment procedures, the surgeon typically does this prior to medial ligamentous reconstruction in order to facilitate proper tensioning and fixation.^4,12-13 It is imperative to have proper osseous alignment and soft tissue balancing for valgus ankle deformity in a patient with a total ankle replacement. We offer this novel technique of repairing the medial deltoid complex with an extensor digitorum longus autograft for patients with a total ankle replacement as a viable alternative to previously described techniques.

Case Study: Step-By-Step Insights Into The Surgical Treatment Of An Active Elderly Man With Painful Bilateral Feet And Ankles

An elderly active gentleman presented with a chief complaint of painful bilateral feet and ankles (see photos A and B). Over the course of the past 10 years-plus, the patient related that his ankles and feet had slowly “rolled inward,” and become increasingly more painful. The patient was active, wanted to maintain a physical lifestyle and did not want an ankle fusion. In particular, the patient wanted to have range of motion of his ankles for ambulation. The deformity in his left lower extremity was limited to being below the ankle joint.

For the left foot, we performed a gastrocnemius recession, a medial double arthrodesis and a tarsometarsal arthrodesis (see C photos). After successful fusion and realignment of the left lower extremity, the patient underwent a gastrocnemius recession, a realignment triple arthrodesis and repair of the deltoid ligament of the right lower extremity. Photo D demonstrates pre-op radiographs of the right foot and ankle. Intra-operative stress views (see photo E1) demonstrate the incompetent medial deltoid ligament intra-operatively under a stress examination. Surgically, there was no evidence of any remaining deltoid ligament (see photo E2). The goal of the surgery was to realign the right lower extremity (keep the foot under the leg).

We identified the fourth extensor digitorum longus (EDL) and harvested approximately 9 cm of the EDL (see photos F1 and F2). We then identified, isolated and tentomized the fourth extensor digitorum brevis (EDB) at the level of the fourth metatarsophalangeal joint. Then we inserted an 0.62 inch k-wire into the distal aspect of the fourth toe into the middle phalanx, the proximal phalanx and into the base of the fourth metatarsal, holding the fourth toe into a neutral position. We proceeded to insert the proximal stump of the fourth EDB via a weave graft into the distal stump of the cut/tenotomized fourth EDL under physiologic tension. Placing the fourth EDB under physiologic tension allows dorsiflexion of the fourth toe postoperatively. Although it is weaker than the fourth EDL, insertion of the fourth EDB into the distal stump of the fourth EDL allows for continued function and dorsiflexion of the fourth digit.

After completing the triple arthrodesis and checking clinically and via fluoroscopy that the foot was physically under the leg and in a more anatomic alignment, we stabilized the ankle with temporary fixation and used the harvested fourth EDL tendon to recreate the medial deltoid ligament under physiologic tension utilizing multiple knotless anchors (see Photo G).

We divided the harvested fourth EDL tendon up into four different pieces to create and replicate the medial deltoid ligament. After placement of the four different autografts under physiologic tension, we removed the temporary fixation from the ankle and stressed the newly developed medial deltoid ligament under fluoroscopy (see Photo H). The ankle joint and newly created autogenous deltoid ligament were well maintained. We had the patient placed in  a below-knee cast and he was immobilized for approximately  two months. At approximately two months, the patient transitioned into a CAM boot for an additional two months and subsequently utilized an ankle brace.

At six months postoperatively, a CT scan and the stress test of the medial deltoid both came back positive for a solid fusion of the triple arthrodesis and competency of the surgical correction of the medial deltoid ligament. With the following positive results, the osteoarthritic ankle maintained neutral alignment and we prepared the ankle for insertion of a total ankle replacement. At two and a half years postoperatively, the patient maintains a well balanced foot and ankle that remain in good anatomical alignment (see Photo I).

An Overview Of Other Techniques For Deltoid Ligament Reconstruction

There currently is no gold standard for reconstructing the deltoid ligament in a total ankle replacement. Several investigators have proposed autograft or allograft tendon reconstruction procedures, but there is a lack of long-term evidence demonstrating effective host repair.^14-18

Deland and colleagues described a technique of utilizing the peroneus longus, routing it through the talus and anchoring it into the medial malleolus.¹⁶ Ellis and coworkers also reported on using this technique with Achilles tendon allograft but the technique does not recreate the superficial ligament.¹⁹ Roukis and colleagues suggest using a modified reverse peroneus brevis to reconstruct the deltoid ligament in medial ankle instability but long-term studies are needed to determine longevity of the construct.²⁰

Jeng and coworkers discussed the use and anchoring of hamstring graft into the medial malleolus, talus and calcaneus in order to recreate superficial and deep deltoid ligaments.¹⁸ Other researchers have described the use of anterior tibial tendon, plantaris tendon or semitendinosus tendon.^21,22 Schuberth and colleagues described a staged technique performing deltoid repair that incorporated autograft, hindfoot fusion as necessary, bone cement in the ankle and a transarticular screw with the performance of total ankle arthroplasty six to eight weeks later.³

In Conclusion

We offer the aforementioned alternative novel technique to use the fourth branch of the extensor digitorum longus tendon as autograft for ligament repair. The deltoid ligament is important in preventing valgus deformity of the ankle and one should repair this if there is any hope of long-term success of the total ankle implant.

Surgeon experience with total ankle replacement is essential before one attempts to perform the aforementioned technique. The surgeon must also thoroughly understand the center of rotation axis, primary deforming forces and the biomechanical consequences of ligament repair with total ankle replacement as the margin for error is not large. The indications for total ankle arthroplasty will surely broaden as we find a more reliable and reproducible solution for frontal plane ligament reconstruction. In our experience, repair of the insufficient deltoid complex with EDL autograft allows adequate stability in the setting of a total joint replacement.

Dr. DiDomenico is in private practice at Northern Ohio Medcial Specialist in Youngstown, Ohio. He is the Section Chief of the Department of Podiatry at St. Elizabeth Hospital in Youngstown, Ohio. Dr. DiDomenico is also the Director of Fellowship Training of the Reconstructive Rearfoot and Ankle Surgical Fellowship and Residency Training at East Liverpool City Hospital in East Liverpool, Ohio. Dr. DiDomenico is a Fellow of the American College of Foot and Ankle Surgeons.

Dr. Shumway is a second year resident at East Liverpool City Hospital in East Liverpool, Ohio.

Dr. Harris is a first year resident at East Liverpool City Hospital in East Liverpool, Ohio.

References
1.    Myerson MS. Adult acquired flatfoot deformity; treatment of dysfunction of the posterior tibial tendon. Instr Course Lect. 1997;46:393-405.
2.    Myerson MS. Adult acquired flatfoot deformity: Treatment of dysfunction of the posterior tibial tendon. Instr Course Lect. 1997;46:393-405.
3.    Schuberth JM, Christensen JC, Seidenstricker CL. Total ankle replacement with severe valgus deformity: technique and surgical strategy. J Foot Ankle Surg. 2017;56(3):618–627.
4.    Smith JT, Bluman EM. Update on stage IV acquired adult flatfoot disorder: when the deltoid ligament becomes dysfunctional. Foot Ankle Clin. 2012;17(2):351–360.
5.    Rasmussen O. Stability of the ankle joint: analysis of the function and traumatology of the ankle ligaments. Acta Orthop Scand. Suppl. 1985;211:1-75
6.    Rasmussen O, Kromann-Andersen C. Experimental ankle injuries: Analysis of the traumatology of the ankle ligaments. Acta Orthop Scand. 1983;54(3):356-362.
7.    Rasmussen O, Kromann-Andersen C, Boe S. Deltoid ligament:functional analysis of the medial collateral ligamentous apparatus of the ankle joint. Acta Orthop Scand. 1983;54(1):36-44.
8.    Harper MC. Deltoid ligament: an anatomical evaluation of function. Foot Ankle. 1987;8(1):19-22
9.    Earll M, Wayne J, Brodrick C, et al. Contribution of the deltoid ligament to ankle joint contact characteristics: a cadaver study. Foot Ankle Int. 1996;17(6):317-324.
10.    Close JR. Some applications of the functional anatomy of the ankle joint. J Bone Joint Surg Am. 1956;38-A(4):761-781.
11.    Miniaci-Coxhead Sl, Weisenthal B, Ketz JP, Flemister AS. Incidence and radiographic predictors of valgus tibiotalar tilt after hindfoot fusion. Foot Ankle Int. 2017:38(5): 519–525.
12.    Haddad SL, Myerson MS, Younger A, et al. Adult acquired flatfoot deformity. Foot Ankle Int. 2011;32(1):95-111.
13.    Anderson R, Davis W. Management of the adult flatfoot deformity. In: Myerson MS (ed): Foot and Ankle Disorders (1st edition), WB Saunders and Co, Philadelphia, 2000, pp. 1017-1039.
14.    Bluman EM, Myerson M. Stage IV posterior tibial tendon rupture. Foot Ankle Clin. 2007;12(2):341-362.
15.    Kitoaka HB, Luo ZP, An KN. Reconstruction operations for acquired flatfoot: biomechanical evaluation. Foot Ankle Int. 1998;19(4):203-207.
16.    Deland JT, de Asla RJ, Segal A. Reconstruction of the chronically failed deltoid ligament: a new technique. Foot Ankle Int. 2004;25(11):795-799.
17.    Haddad SL, Dedhia S, Ren Y, Rotstein J, Zhang LQ. Deltoid ligament reconstruction: a novel technique with biomechanical analysis. Foot Ankle Int. 2010;31(7):639-651.
18.    Jeng CL, Bluman EM, Myerson MS. Minimally invasive deltoid ligament reconstruction for stage IV flatfoot deformity. Foot Ankle Int. 2011;32(1):21-30.
19.    Ellis SJ, Williams BR, Wagshul AD, et al. Deltoid ligament reconstruction with peroneus longus autograft in flatfoot deformity. Foot Ankle Int. 2010;31(9):781-789.
20.    Roukis TS, Prissel MA. Reverse Evans peroneus brevis medial ankle stabilization for balancing valgus ankle contracture during total ankle replacement. J Foot Ankle Surg. 2014;53(4):497–502.
21.    Williams BR, Ellis SJ, Yu JC, Deland JT. Stage IV adult-acquired flatfoot deformity deltoid ligament reconstruction. Oper Tech Orthop. 2010;20:183-189.
22.    Brunner S, Knupp M, Hintermann B. Total ankle replacement for the valgus unstable osteoarthritic ankle. Tech Foot Ankle Surg. 2010;9:165-174.