Triple Arthrodesis Technique

Updated: Oct 26, 2015
  • Author: Stephen M Schroeder, DPM, FACFAS; Chief Editor: Jason H Calhoun, MD, FACS  more...
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Technique

Approach Considerations

As with most cases, nonsurgical measures should be exhausted before considering surgical intervention. This is especially true when planning a salvage procedure like a triple arthrodesis. Conservative treatment consists of physical therapy, strapping and tapping, nonsteroidal anti-inflammatory drugs (NSAIDs), steroid injections, and bracing.

Most triple arthrodesis procedures are performed by removing all of the cartilage from the three joints involved—that is, the talocalcaneal (TC) joint (also referred to as the subtalar joint [STJ]), the talonavicular (TN) joint, and the calcaneocuboid (CC) joint—and fusing them with bone-to-bone contact. Positional corrections can usually be achieved by rotating the foot along the natural contours of the joint surfaces prior to fusion. In cases of severe deformity, however, wedges of bone may need to be removed from or added to the joints to achieve the desired correction. [2, 3, 5, 6, 7, 8, 9, 10, 11]

One area of controversy regarding this procedure has to do with using external fixation devices. Proponents would argue that this is a stable fixation method that allows patients to ambulate with partial to full weightbearing on the operative side. Others would argue that the risk of pin-tract infections is high and could be disastrous to the procedure's outcome. A study that assessed 87 patients using a ring-style external fixation device reported a 97% fusion rate at 6-8 weeks, with a 36% rate of superficial pin-site infections. [11]

Orthobiologics are playing a growing role in augmenting these procedures. Autologous bone grafting is still the product of choice for filling voids; however, it is associated with a certain degree of morbidity. Allograft bone and other orthobiologic materials are safe and effective alternatives that reduce risks to the patient.

The double arthrodesis has gained popularity over the last few years and involves fusion of the TN and TC joints only. [12] It can be done through a single medial incision, preserves a nonarthritic CC joint, maintains the length of the lateral column, and has been shown to be a reliable method for correcting planovalgus deformity. [13] It is especially beneficial in cases where concern exists for lateral incision wound breakdown, as with compromised skin from previous trauma or a severe valgus deformity. [4, 14, 15, 13]

Arthroscopic triple arthrodesis may be more commonly performed in the future.

Arthroscopic arthrodesis is an accepted technique for the ankle but less commonly reported for multiple hindfoot joints. A case series review by Jagodzinski et al found that arthroscopic double and triple arthrodeses appear to be feasible salvage options for pain and deformity, though late adjacent joint pain and arthrosis may develop. [16]

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Fusion of Talocalcaneal, Talonavicular, and Calcaneocuboid Joints

With the patient properly positioned (see Periprocedural Care, Patient Preparation), a lateral incision is made from just inferior to the distal tip of the lateral malleolus to the base of the fourth metatarsal (see the images below). The TC joint, the CC joint, and the lateral portion of the TN joint are thereby exposed. Care is taken to avoid branches of the sural and superficial peroneal nerves running just inferior and superior to the incision. This approach follows a plane between the two nerves, but small branches may enter the area and should be avoided if possible.

Lateral incision is made from just inferior to dis Lateral incision is made from just inferior to distal tip of lateral malleolus to base of fourth metatarsal. This allows exposure to talocalcaneal (subtalar) joint, calcaneocuboid joint, and lateral portion of talonavicular joint. Care is taken to avoid branches of sural and superficial peroneal nerves running just inferior and superior to incision. This approach follows plane between nerves, but small branches may enter area and should be avoided if possible.
Anatomy of lateral incision: (A) lateral incision, Anatomy of lateral incision: (A) lateral incision, (B) lateral malleolus, (C) base of fourth metatarsal, (D) base of fifth metatarsal, (E) peroneal tendons, (F) sural nerve, (G) intermediate dorsal cutaneous nerve.

The deep fascia is visualized through the entire course of the incision, and the extensor digitorum brevis (EDB) muscle belly is identified. An L-shaped incision is made through the deep fascia traveling along the course of the EDB insertion and then distally across the CC joint (see the image below). This releases the insertion of the EDB, allows access to the CC joint, and gives exposure to the sinus tarsi and the Hoke tonsil. The EDB muscle belly is flapped distally, starting at its proximal lateral margin, giving excellent exposure to the CC joint and allowing eventual exposure to the lateral TN joint.

Deep structures encountered through lateral incisi Deep structures encountered through lateral incision: (A) Hoke tonsil before removal, (B) L-incision along insertion of extensor digitorum brevis (EDB) and across calcaneocuboid joint, (C) deep fascia over EDB.

The Hoke tonsil is next evacuated by carefully following the contours of the calcaneus with a No. 15 blade, beginning at the anterior process (see the image below).

(A) Extensor digitorum brevis elevated to expose ( (A) Extensor digitorum brevis elevated to expose (B) calcaneocuboid joint. (C) Hoke tonsil.

Care should be taken to identify and protect the peroneal tendons. All of the contents of the sinus tarsi should be removed, including the interosseous ligament, to gain exposure to the anterior portion of the TC joint.

A laminar spreader is placed into the sinus tarsi and used to open the TC joint, vertically separating the talus from the calcaneus. Transection of the calcaneofibular (CF) ligament may become necessary in cases where the joint remains tight and adequate exposure is not achieved. Articular cartilage is removed from the anterior, middle, and posterior facets by scraping with a curette or stripping with an osteotome.

The remaining subchondral bone is then fenestrated by using a 0.062-in. K-wire, a small drill bit, or a power bur. This allows vascular ingrowth through the subchondral plate and excellent bone preparation for fusion. Another method for penetrating the subchondral bone is to use a small osteotome or gouge to shingle the articular surface.

Attention is next directed to the CC joint, where the cartilage is denuded, leaving only subchondral bone. The surfaces are fenestrated in the fashion described above. Care should be taken to leave as much bone as possible at this joint, especially in valgus deformities, because lateral column length is important for correction. The lateral border of the TN joint can be reached after the CC joint is prepared by dissecting directly medially.

A capsulotomy is performed, and the laminar spreader is once again used to separate the articular surfaces. Any cartilage that can be removed through this incision should be before starting the medial approach.

A medial incision is made beginning just anterior to the distal tip of the medial malleolus extending dorsomedially toward the naviculocuneiform joint (see the images below). It lies between the anterior and posterior tibial tendons. The saphenous vein and nerve are typically located slightly dorsal to the incision and should be carefully retracted away during the dissection.

Medial incision is made beginning just anterior to Medial incision is made beginning just anterior to distal tip of medial malleolus extending dorsomedially to naviculocuneiform joint. It lies between anterior and posterior tibial tendons. Saphenous vein and nerve are typically located slightly dorsal to incision and should be carefully retracted away during dissection.
Anatomy of medial incision: (A) medial incision, ( Anatomy of medial incision: (A) medial incision, (B) medial malleolus, (C) posterior tibial tendon, (D) tibialis anterior tendon, (E) saphenous vein.

A capsulotomy of the TN joint is performed in line with the skin incision, and periosteal flaps are created to expose the articular surface. A laminar spreader is inserted for exposure, and the cartilage is removed. The articular surface of the navicular is usually deeply concave, making cartilage excision difficult. Care must be taken to ensure that the entire surface is properly denuded in order to avoid healing problems. Osteophytes and a large medial tubercle on the navicular can be removed, if present.

Next, the foot is manipulated into the corrected position, and bone-on-bone contact at each joint is confirmed. Larger deformities may require that wedges be removed for optimal correction. Small gaps in joints can be filled with bone graft to help ensure solid union.

Once it has been established that the foot will reduce properly, it is temporarily fixated. The TC joint should be placed in about 4° of valgus relative to the ground. It is extremely important to not leave the hindfoot in varus; doing so will most certainly lead to postoperative complications. A helpful thought to keep in mind during this procedure is "Thou shall not varus!" The forefoot is then aligned plantigrade to the floor.

Fixation techniques vary and often depend on the surgeon's preference.The TC joint should be fixated with a cannulated 6.5 or larger screw, which can be placed from the posterior plantar portion of the calcaneus into the body of the talus or from the neck of the talus into the body of the calcaneus (see the images below). Care should be taken not to disrupt nutrient arteries entering the neck of the talus if the latter approach is used.

Lateral view showing talocalcaneal (subtalar) join Lateral view showing talocalcaneal (subtalar) joint arthrodesis with 7.3 cannulated screw going from talus to calcaneus.
Lateral view showing talocalcaneal (subtalar) join Lateral view showing talocalcaneal (subtalar) joint arthrodesis using a 7.0 cannulated screw from calcaneus into talus.

Newer headless screws are useful with this technique, in that there is less chance of impingement on the tibia during dorsiflexion of the ankle joint. This can also be a timesaver because the area is highly accessible after the TN joint has been exposed. A secondary point of fixation is used if there is concern for rotational instability. The TN and CC joints can be fixed with either staples or screws. If staples are used, at least two are placed in each joint, directed at 90° angles to each other. The use of compression staples and locking compression plates has greatly enhanced this technique and should be considered over the use of antiquated standard staples.

The technique preferred by the authors is to use two or three 4.0-4.5 cannulated screws placed parallel to each other in the TN and CC joints and to use a single 7.0-7.3 cannulated screw in the TC joint (see the image below). This technique works very well and saves time because the guide pins are used as temporary fixation. Once the pins are in place, the corrected position is verified with fluoroscopy, and the screws are easily placed over the guide pins. Headless screws should be considered at the surgeon’s discretion. Two- or four-hole locking compression-style plates have also been used at the CC [17] and TN joints, providing excellent stability, compression, and time savings.

Subchondral bone in joint with degenerative joint Subchondral bone in joint with degenerative joint disease can be very sclerotic and hard. It may be wise to extend guide hole from near cortex in navicular all the way through talonavicular joint and into talus, even when using cannulated screws that are self-drilling and self-tapping. Corkscrew-appearing hardware represents threads from cannulated screw that delaminated off implant during attempt to cut through subchondral bone in talar head.

Hardware placement is verified with fluoroscopy, and residual gaps in joints, including the sinus tarsi, are filled with bone graft. The surgical sites are closed in layers, with care taken to repair the CF ligament and the insertion of the EDB. A lateral drain should be used to help prevent hematoma formation, especially when large portions of bone are resected. If a preoperative block was not performed, an ankle block with 0.5% plain bupivacaine is performed to help decrease postoperative pain. Finally, a Jones-style compression dressing is applied with a posterior splint before deflation of the tourniquet.

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Postoperative Care

Patients are usually kept overnight in the hospital for observation, pain control, and intravenous (IV) antibiotics. Anticoagulation therapy is started if deemed necessary.

After discharge, patients are instructed to spend at least the first 5 days with their foot elevated above their heart in order to control edema and pain. The patients are seen within 1 week for a dressing change, and a short leg cast is applied if the edema is controlled. Sutures are removed after 2 weeks, and the patient is placed back into a nonweightbearing (NWB) cast. The authors have also used external electric stimulation from postoperative day 1 on in higher-risk patients with good success, and the benefits of this approach have been confirmed by other authors. [18]

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Complications

Because of the complex nature of the procedure and the various disease states being treated, complications after triple arthrodesis are relatively common. The following are the ones most frequently encountered.

Nonunion

As with any type of arthrodesis procedure, nonunion is a potential complication. In the case of the triple arthrodesis, the TN joint is the most common site of nonunion, with most studies reporting a rate of 5-10%. This is probably related to poor preparation of the joint surfaces, which are difficult to expose, especially if only a single lateral incision is used. Adding a second medial incision provides much better access to the joint and allows a more aggressive capsule release as well as easier distraction and better exposure for complete cartilage removal. A cadaveric study by Bono showed that only 38% of the cartilage from the TN joint was successfully removed via a lateral incision alone. [8]

Degenerative joint disease

A properly functioning foot goes through a multitude of movements with each phase of the gait cycle. A high degree of these movements takes place at the TC, TN, and CC joints. Most foot pronation and supination occurs around these joints. Once the three joints are fused, a large amount of stress is transferred to the joints immediately proximal and distal. Midfoot degenerative joint disease (DJD) can develop with time. An important intraoperative consideration is foot position. Excessive varus or valgus alignment of the rearfoot or forefoot can accelerate the onset of DJD. [14]

Delayed wound healing

Many of these patients are elderly or debilitated from an underlying disease process that requires chronic steroid therapy. These issues can lead to delayed wound healing most commonly seen as a mild dehiscence at the edges of the incision. Excessive postoperative edema can also delay healing. A rare situation that can cause large amounts of skin slough is placing the lateral tissues on stretch after reducing a large valgus deformity. This is a good indication for an isolated TN-TC arthrodesis through a medial approach if there are no arthritic changes seen at the CC joint. [15]

An important point that must also be appreciated is the relatively small amount of subcutaneous and fatty tissue in the foot. Dissection should be meticulous, with delicate handling of tissues, and healthy full-thickness skin flaps need to be maintained..

Nerve injury

Both the lateral incision and the medial incision are placed close to underlying nerves. The lateral incision lies between the sural and the superficial peroneal nerves. Small branches from each may be transected during the procedure. The intermediate dorsal cutaneous nerve, which is an extension of the superficial peroneal nerve, is located very close to the distal portion of this incision. Variations of these nerves do exist and can cross the path of the standard lateral incision; thus, careful dissection is warranted. The medial incision is located in proximity to the saphenous nerve as well as the medial dorsal cutaneous nerve at the distal margin of the wound.

Entrapments within surgical scar tissue can take place in the postoperative period; however, painful neuromas rarely occur. When they do happen, standard conservative measures with appropriate medications, injections, and physical therapy should be employed. If these measures fail, surgical neurolysis or proximal neurectomy with implantation into muscle is performed.

Avascular necrosis

Avascular necrosis is a rare complication but has been reported. [9] The predominant bone affected is the talus. In most instances, it results from disruption of the blood supply in the course of accessing the TC joint, resection of a large portion of the talar head to increase correction of deformity, or excessive dissection of the talar neck during placement of a screw from the talus down into the calcaneus.

Lateral instability

Lateral instability occurs for two main reasons. The first is malposition of the rearfoot in varus leading to excessive lateral stress on the ankle joint postoperatively. The other is inherent to the procedure: For adequate exposure to the TC joint, it is often necessary to transect the CF ligament, and if this ligament does not heal properly, lateral ankle instability can result.

Stiff foot

Stiff foot is not so much a complication of the procedure as it is a result of the procedure. The motions of pronation and supination around the TC joint allow the foot to adapt over uneven terrain. When the TC joint is pronated, the entire foot becomes flexible. Conversely, when the STJ is supinated, the entire foot becomes rigid. These motions are normal and allow for shock absorption and conformation to surface terrain when pronated and propulsion when supinated.

Once the three joints are fused, the foot becomes stiff and loses flexibility. This should be explained to the patient before surgery as something to expect postoperatively. Ankle motion is also affected. One report showed a 13% decrease in dorsiflexion and a 16% decrease in plantarflexion. [10]

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