The Lateral Incision

The incision is made from the tip of the fibula extending distally down over the sinus tarsi toward the CC joint ( Fig. 30.4 andVideo 30.1 ). On the inferior surface of the incision, the peroneal tendon sheath is identified, and the terminal branch of the sural nerve must be looked for more distally in the incision. Both the peroneal tendons and the sural nerve are retracted inferiorly, and the incision can be deepened down on the periosteum directly over the calcaneus. The incision is extended distally toward the CC joint and then further toward the base of the fourth metatarsal. In the terminal aspect of the incision, care must be taken to ensure that no branches of either the sural or lateral cutaneous branch of the superficial peroneal nerve are present. The retinaculum of the undersurface of the peroneal tendon sheath is stripped and elevated off the lateral wall of the calcaneus. We prefer to save the contents of the sinus tarsi, because in the event of a wound dehiscence, sufficient tissue may be present for covering the peroneal tendons. The soft tissues are elevated sharply off the floor of the sinus tarsi until the anterior aspect of the posterior facet of the subtalar joint is visualized.

Lateral incision for hindfoot arthrodesis. The incision is marked out from the tip of the fibula across the sinus tarsi.

The incision is deepened directly onto the periosteum along the CC joint, and a large periosteal elevator is used to strip the lateral aspect of the calcaneus and then the cuboid. The peroneal retinaculum is retracted inferiorly, and a knife blade is inserted directly into the CC joint and then manipulated dorsally to cut the cervical ligament. The knife blade is swept vertically through the CC joint and then rotated dorsally across the bifurcate ligament and directly into the posterior facet with one maneuver. The cuboid bone should now be freely mobile, and the articular surface of the entire joint is denuded with a 2-cm flexible chisel, as well as with a rongeur and curette. Removal of more than 2 mm of bone and cartilage on either side of the joint is unnecessary. An important point here is that regardless of the type of deformity, a lateral bone wedge is not removed, and the position of the hindfoot is corrected with translation and rotation, not with resection of bone wedges. A laminar spreader is inserted into the CC articulation to check that all of the cartilage has been removed. Care must be taken to ensure that a minimal amount of bone is resected, to minimize any shortening of the lateral column. A saw may be used to remove the subchondral bone and the remaining cartilage simultaneously. Although this technique is highly efficient, the risk of heat necrosis and excessive shortening must be considered. We prefer not to use a tourniquet when using this technique to minimize heat necrosis and risk of nonunion and do not advocate this maneuver in the setting of a flatfoot given the shortening that will occur.

A laminar spreader is inserted into the sinus tarsi, and when it is placed on stretch, the interosseous ligament is easily visualized and cut to gain access to the posterior aspect of the subtalar joint and the middle facet. A 1-cm flexible chisel or osteotome is used to denude the articular surface of the posterior facet. As with the CC joint, minimal bone is removed. The use of curette directed from posterior to anterior is effective at removing any loose or remaining cartilage. Irrigation is used to clear out debris to accurately visualize any remaining articular cartilage to ensure a thorough joint preparation is performed. The posterior facet must be debrided down to bleeding healthy subchondral bone ( Fig. 30.5 ). Care is taken with the debridement of the posteromedial corner of the joint, where the flexor hallucis longus tendon is at risk for injury from the chisel. Finally, the more medial aspect of the subtalar joint and the middle facet must be completely denuded, including the undersurface of the talus and the dorsal surface of the middle facet. Before the medial incision is made, the space between the navicular and the cuboid is debrided with a rongeur. This debridement adds another segment and bone surface to the fusion mass and converts the triple arthrodesis to a “quadruple arthrodesis” ( Fig. 30.6 ). The TN joint is clearly the most difficult of the three joints to visualize and to debride adequately. With either a varus or valgus deformity, the TN joint is only partly visible, but it must be distracted to permit visualization in its entirety. It may be tempting to approach the TN joint from the lateral incision, but only one-third of the joint is visible from this incision, perhaps more if the hindfoot is fixed in varus. Of note, however, the TN joint is the one joint that will end up in nonunion if the joint debridement is not performed carefully. The medial incision is made medial to the anterior tibial tendon, extending from the ankle toward the medial cuneiform bone ( Fig. 30.7 ). The extensor retinaculum is incised, and the anterior tibial tendon is retracted laterally, exposing the deep subcutaneous tissue. Partially cutting into the extensor retinaculum and the medial edge of the anterior tibial tendon more distally may be necessary at times, because the tendon blends into the fibers of the retinaculum.

(A) The subtalar joint is visible with insertion of a laminar spreader, which pushes the joint anteriorly. (B) Debridement is performed using a flexible chisel. Note the protection of the peroneal tendons by means of a curved retractor placed behind the subtalar joint.

(A and B) The local anatomy of the junction between the talus, navicular, cuboid, and calcaneus. The junction of these four bones is the fourth joint in a so-called “quadruple arthrodesis.”

Intraoperative photo demonstrating the position of the incision immediately medial to anterior tibial tendon (A). Exposure of the joint is facilitated with the use of a pin distractor, allowing for excellent visualization of talus ( T ) and navicular ( N ) joint (B). Preparation of the joint is performed with an osteotome (C). Final preparation of the joints with a 2.5-mm drill bit is seen, with clear visualization of the talus and navicular (D and E). Preoperative lateral and postoperative lateral and anteroposterior foot radiographs following the arthrodesis (F). This exposure allows placement of two parallel screws from the navicular to the talus allowing for maximal compression with additional placement of a screw from the navicular to calcaneus maximizing torsional rigidity. One-year clinical photographs of the patient demonstrating the healed incision (G).

After the dissection, a retractor is inserted to pull aside the anterior tibial tendon and the medial soft tissues. The periosteum along the navicular bone is stripped, and then the TN joint is fully exposed with a curved periosteal elevator. Inserting an elevator directly into the joint to fully expose the head of the talus, followed by further stripping of the soft tissue dorsally and laterally, is useful. When a severe valgus deformity is corrected, pushing the midfoot into varus and then loosening the tension of the medial TN joint are helpful. We then cut around the medial joint from the outside in, through the remnant of the posterior tibial tendon and spring ligament into the TN joint. This step makes opening and distraction of the joint far easier. A smooth laminar spreader ( Fig. 30.8A ) or rongeur is inserted into the joint and then exchanged for a toothed laminar spreader to facilitate distraction of the joint. This, however, may crush the joint surface and is not our preferred method of joint exposure, which is to use a pin distractor or by using pins inserted through a laminar spreader through which distraction can be applied (see Fig. 30.8B ). The entire joint is denuded of cartilage using a 1-cm flexible chisel. An important consideration with the navicular is that because this bone can be hard, it can fragment if not debrided gently. The same contour must be maintained with debridement of the talar head while a small flexible chisel is used. Presence of osteopenia increases the risk of injury with use of the laminar spreader, which may crush into the talus. At the completion of the joint debridement, surfaces should appose well, with maintenance of the overall joint contour. If bone is resected from either joint surface, the medial column of the foot will be shortened, followed by a varus malunion.

(A) The talonavicular joint can be exposed by inserting a laminar spreader into the joint. (B) Alternatively, pins can be inserted through a laminar spreader to distract the joint.

Once the joints have been adequately visualized and their surfaces debrided, the final preparation is accomplished with a 2.0- or 2.5-mm drill bit to thoroughly perforate each bone surface. This aspect of the procedure is particularly important when the bone is sclerotic, which is often the case with the navicular. A Kirschner wire (K-wire) is associated with increased heat generation relative to a drill and this is not preferred for joint preparation.

Reduction of Deformity and Fixation

The reduction maneuver of the hindfoot relative to the forefoot is critical (Video 30.1 ). For most deformities, the hinge point is the TN joint; therefore this is the joint that we reduce and fix first. The foot is rotated around the axis of the TN joint, and as the forefoot is adducted, the first metatarsal is plantarflexed to correct the forefoot relative to the hindfoot ( Fig. 30.9 ). This maneuver is unsuccessful only when the subtalar joint is rigid and the calcaneus is laterally translated, in which case we fix the subtalar joint first. In the latter instance, then the TN joint may not line up perfectly, although clinically the forefoot alignment may appear to be corrected. For some very severe deformities that feature gross posterior subluxation of the subtalar joint, it is helpful to address this problem first by inserting a laminar spreader between the anterior process of the calcaneus and the lateral process of the talus ( Fig. 30.10 ). This maneuver forces the calcaneus forward, reducing the subtalar subluxation.

Manipulation of the hindfoot before fixation of a talar arthrodesis. (A) Valgus of the hindfoot. (B) With manipulation of the hindfoot around the axis of the talonavicular (TN) joint, the heel assumes a neutral position. (C) The forefoot is adducted and pronated around the TN joint while the joint is palpated (using the index finger) for reduction.

Placement of a laminar spreader between the lateral process of the talus and the anterior process of the talus can help with reduction of a posterior subluxated subtalar joint. Excessive distraction can occur with diastasis of the talonavicular (TN) joint and should be avoided, with reduction assessment and TN joint position verified by fluoroscopy before fixation.

In the past, we routinely used cannulated screws for fixation of the arthrodesis of each of the joints, and for the most part we still prefer screws for fixation. We currently use one 6.5- or 7.0-mm cannulated screw for the subtalar joint and one or two 4.5- to 5.5-mm screws for the CC and TN joints. The specific screw diameter is dependent on which implant company is preferred. We have noted, however, that it is difficult to obtain good placement of screws across the TN joint. One screw is easy to insert from the plantar medial aspect of the navicular, but the available space is not always sufficient for a second screw, and even use of two screws inserted from the medial aspect of the joint does not provide adequate fixation of the dorsal joint surface ( Fig. 30.11 ). The fixation of the TN joint may then be quite inadequate, because the joint is compressed predominantly medially, which may be associated with a delayed union or even nonunion of the joint fusion ( Fig. 30.12 ). If we are not satisfied with the fixation in the TN joint after placement of one or more screws, we supplement this with a nitinol compression staple or dorsal two-hole locking compression plate ( Fig. 30.13 ). The use of nitinol compression staples for the Chopart joint can be considered in the setting of a triple arthrodesis as an alternative to screw fixation ( Fig. 30.14 ). If isolated staple fixation is considered, two staples should be placed across each joint to ensure rigid fixation and improve angular stability.

(A and B) Two guide pins for cannulated screws were inserted across the talonavicular (TN) joint, and one was inserted across the subtalar joint. Despite presence of the two pins, a large segment of the TN joint is without any fixation or stabilization.

A nonunion resulted despite what appears to be satisfactory screw fixation of the hindfoot. The talonavicular joint is the one most likely to be involved in nonunion.

(A–C) This rigid flatfoot deformity was treated with a modified triple arthrodesis (double arthrodesis). (D and E) The fixation initially obtained with one screw across the talonavicular joint was not adequate and was therefore supplemented with application of a two-hole locking compression plate dorsally. Note that the declination of the talus is still not ideal, and this could have been improved with a Cotton osteotomy or an arthrodesis of the first tarsometatarsal joint.

This patient underwent a revision of a prior flatfoot correction that resulted in a stiff painful hindfoot. Preoperative and postoperative radiographs (A–C) are presented demonstrating deformity correction with use of large nitinol compression staples (DePuy Synthes, West Chester, United States) for fixation of the Chopart joint.

We generally begin with the TN joint fixation for patients with primarily an abduction deformity. One or two guide pins are inserted into the TN joint, the first from the inferior medial tuberosity and the second from a slightly more dorsal location, immediately adjacent to the anterior tibial tendon. The head of the second, more dorsal screw will be close to the naviculocuneiform joint. The heads of all screws must be well buried flush with the margin of the bone and not protrude into the naviculocuneiform joint. As noted, this configuration of screw fixation will provide fixation and compression of the medial aspect of the TN joint only. To improve the surface area that is compressed, use of a dorsolateral screw in parallel to the medial screw or a dorsolateral staple/plate is advocated. The use of a screw from the navicular to the calcaneus will improve torsional rigidity; however, the clinical superiority of this screw has not been defined. We only use this screw from the navicular into the calcaneus when the anatomy of the joint is difficult for other methods of fixation.

A few alternatives are available for insertion of the subtalar joint screw. The traditional method is to introduce a guide pin from the undersurface of the calcaneus, but off the weight-bearing surface of the heel. The problem with this method is that pin placement is not always accurate and the screw is frequently not exactly in the body of the talus. Another method is to insert the guide pin from the top of the talus just anterior to the ankle joint and then direct the guide pin all the way out the back of the heel. This maneuver permits determination of the exact starting position of the guide pin in the center of the talus. The pin is pulled out of the heel until the length in the body of the talus is correct, and then the screw is introduced from the heel up into the talus. The use of a headless screw may be considered to avoid late hardware irritation and the need for removal. Given the low profile (buried under the tuberosity) of a headless screw, the screw may be placed from the weight-bearing aspect of the calcaneus, which allows for the screw trajectory to be angulated more vertical, facilitating placement into the center of the talar body. In general, when a triple arthrodesis is performed, only one screw is placed across the subtalar joint, given the increased rigidity to the subtalar joint imparted by the TN fusion.

The CC joint is fixed last, using a posterior-to-anterior approach. The lateral aspect of the CC joint is flat, and screw insertion will not be easy unless the surface of the calcaneus is prepared by making a notch with a chisel 1 cm proximal to the articular surface ( Fig. 30.15 ). This step is important in obtaining a solid fusion, and the lateral aspect of the foot must be elevated across the CC joint. Although the TN and subtalar joints are already fixed, some lateral mobility will still be present, and if the cuboid bone drops down, weight bearing will be painful as a result of a malunion. It is therefore imperative to elevate the inferior aspect of the cuboid, to create a plantigrade lateral weight-bearing surface. The guide pin for a 5.5-mm screw is inserted across the notched surface into the CC joint, followed by a 35-mm partially threaded screw. If the joint surface is very flat and a screw cannot be easily inserted, then use of a small locking compression plate is ideal (Orthohelix, Akron, United States) ( Fig. 30.16 ). The use of a compression nitinol staple may be considered for the CC joint as well.

(A) To permit insertion of a screw across the calcaneocuboid joint without fracture, a notch was cut in the lateral calcaneus 1 cm proximal to the joint. (B) The screw was then inserted percutaneously into the notch.

(A) A triple arthrodesis was performed for management of posttraumatic arthritis of the hindfoot associated with avascular necrosis of the talus. (B and C) Owing to the anatomy of the foot, it was far easier to use plates supplementing the screw fixation on the talonavicular and calcaneocuboid joints. Note that a structural bone graft has been inserted into the subtalar joint to increase the height of the hindfoot and improve the talar declination angle, which was markedly abnormal preoperatively.

Once fixation has been completed, the stability of the ankle should be checked, particularly with those procedures that are performed for a severe valgus deformity. As a result of the chronic valgus impingement between the calcaneus and the fibula, there is frequently erosion of the calcaneofibular ligament leading to ankle instability. In the case illustrated in Fig. 30.17 , gross instability was noted after screw fixation, and repair was accomplished with a modified Chrisman-Snook procedure.

(A) After screw fixation, gross instability on inversion stress was noted. (B) The incision for the triple arthrodesis was extended proximally, and the peroneus brevis tendon was identified. (C) The tendon was split, and a 4.5-mm drill hole was made in the fibula. (D) The tendon was pulled through posteriorly, and a screw was pulled through the tendon over a spiked ligament washer. (E) The screw was then fixed into the calcaneus with the tendon under appropriate tension.

There are types of deformity that are more amenable to an alternative approach to the standard triple arthrodesis outlined previously. In particular, where there is a cavus or equinus deformity with the apex at the navicular, a modified triple described as a “beak” arthrodesis can be performed where the navicular is slid into a slot cut in the talar head. The dorsal and proximal articular surfaces of the navicular are cut sharply with a small saw, and a reciprocal cut is made in the head of the talus to receive the navicular. This then allows the cavus deformity to be corrected into a more neutral planar position in the sagittal plane ( Fig. 30.18 ).