Location of Pain

To allow the patient to correctly identify the area of discomfort, both feet and ankles should be exposed during the physical examination. Patients with isolated ankle arthritis present with pain localized anteriorly in the ankle between the malleoli. Swelling may occur in the same area, and the pain is localized above and between the tips of the malleoli.

Talonavicular joint pain is localized anterior to the ankle and malleoli and down toward the tuberosity of the navicular. Swelling occurs anterior to the ankle and onto the dorsum of the foot. Because the superior joint margin of the talonavicular joint is only 1 to 2 cm in front of the anterior margin of the ankle joint, talonavicular arthritis can be confused with ankle arthritis.

Subtalar joint pain is localized in the sinus tarsi inferior to the lateral malleolus. Medially, pain is localized directly inferior to the medial malleolus.

Degree of Disability

Patients should be assessed for their degree of disability. Their walking tolerance and standing tolerance are good indicators of disability. They might have had to stop work because of the hindfoot pain. Sports might have been permanently discontinued or restricted due to pain or instability. Before treatment, the degree of disability should be outlined to determine success of intervention.

Comorbidities

Patients with hemophilia should be followed closely by the hematologist if surgery is contemplated. Their ability to be anticoagulated before and after surgery should be assessed.

Patients with rheumatoid arthritis should be optimized with regard to medical treatment. Other joint involvement should be assessed and the degree of associated disability known. Only in exceptional circumstances should the foot or ankle undergo fusion if another joint is more symptomatic.

Extra-articular manifestations of rheumatoid arthritis include iritis, cardiomyopathy, conduction delays, respiratory disease, and skin breakdown. A systemic evaluation is required.

Bone Deformity

When there is erosion of the medial or lateral side of the joint, a standard arthroscopic fusion can be performed and augmented by correction of the deformity by sculpting of the prominent side of the joint with a burr to allow correction of the varus or valgus plane deformity. Removal of some of the tip of the medial or lateral malleolus may be required to allow joint compression. The edge of the bone deformity often is located within the joint and can indicate where to start applying the burr to reduce the deformity. The degree of bone removal can be estimated using intraoperative fluoroscopy.

After correction is achieved in the varus and valgus plane, the talus can be corrected using a Kirschner wire or drill from the lateral or medial malleolus. Any defect left gapping on one side can be filled with bone graft or bone graft substitute. A screw is first placed through the malleolus to the talus to hold the correction, and the opposite side of the ankle is compressed with two or three compression screws.

Extensive Osteophyte Formation

In cases with extensive osteophyte formation, the joint may be difficult to instrument with an arthroscope. This situation usually requires an open procedure, but in cases in which the soft tissue complications may merit arthroscopic fusion, it can be performed. However access to the joint may take some time and patience.

Osteophytes can be identified for removal by fluoroscopy before arthroscopy (Fig. 19-1). The osteophytes can be removed through the standard anteromedial and anterolateral arthroscopic portals using a small metatarsal osteotome. The bone fragments must be removed with care so as not to damage the deep branch of the peroneal nerve or its superficial branches. Alternatively, a 3.5- to 4.0-mm, round burr may be used from the medial and lateral approaches to remove the bone spurs under direct visualization. It may be useful to decrease the joint distraction and to dorsiflex the ankle, which allows the anterior joint capsule to relax during removal of anterior tibial and talar neck osteophytes.

FIGURE 19-1 C-arm view shows osteophyte removal before arthroscopy in a tight joint.

The Tight Joint

In some cases, the tight ankle cannot be easily accessed for an arthroscopic fusion. After release of the osteophytes as described earlier, the joint may have to be instrumented with the assistance of fluoroscopy. The joint line can be hard to find, and gradual opening of the joint is required until the arthroscope can be inserted (Fig. 19-2).

FIGURE 19-2 The C-arm is used to identify the joint line during arthroscopy in a tight joint (same patient as in Fig. 19-1).

Instrumentation

A 2.7-mm-diameter arthroscope works well for the ankle joint but may be a tight fit for the subtalar fusion, and a 1.9-mm-diameter arthroscope should be available. It is useful to have arthroscopes with 30- and 70-degree viewing angles available for small joint arthroscopy. Otherwise, the surgeon should have a 3.5-mm shaver and a selection of small, straight and angled curettes available. These instruments usually fit the ankle and subtalar joints. Intraoperative fluoroscopy is essential for the procedure.

Technique

The patient is positioned on the operating table with the hip on the surgical side elevated to allow access to the lateral ankle and subtalar joint (Fig. 19-3).³ Distraction can be performed using an external distraction device to improve access to the joint. Alternatively, distraction can be performed for the ankle fusion using an Ace Wrap around the surgeon’s waist.

FIGURE 19-3 Positioning is shown for arthroscopic ankle and subtalar fusion. Notice the position of the foot, with the toes pointing toward the ceiling.

The ankle joint is approached first. The anteromedial and anterolateral portals are used to débride the anterior ankle joint. Posterior débridement requires a posterior portal. I use a portal just behind the medial malleolus. Anatomic dissections have documented that this portal passes posterior to the tibialis posterior tendon and usually passes anterior to the flexor digitorum longus. Alternatively, a standard posterior lateral portal can be used. This approach requires working around the fibula. However, care should be taken not to damage the tibial nerve during the use of both posterior portals. The posterior joint is difficult to débride without using a posterior portal in all but the most lax ankle joints.

After the ankle joint has been completely débrided, the subtalar joint is approached from the lateral portals. Anterolateral, direct lateral, and posterolateral portals are used. The foot is inverted to allow access while the surgeon sits on the lateral side of the table while working the portals of the subtalar joint. Sequential débridement is performed of the posterior facet of the subtalar joint using standard techniques.

After both joints have been débrided, the instruments are withdrawn, and the joints are held in a neutral position. A retrograde rod is the preferred method of fixation in these cases, because its insertion requires minimal exposure while providing a strong mechanical construct.

Retrograde Rod Technique

An incision is made on the plantar aspect of the foot directly in line with the long axis of the tibia with the foot in the corrected position. The starting point can be confirmed on anteroposterior and lateral image views before the incision is made. The starting point usually is 1 to 2 cm behind the calcaneocuboid joint and on the medial slope of the calcaneus (Fig. 19-4). Care should be taken when exposing this part of the calcaneus from the plantar side to ensure that the tibial nerve is not damaged. The nerve lies on the medial side of the approach. Deep dissection should be performed bluntly and the medial soft tissues retracted.

FIGURE 19-4 A and B, A hemophiliac patient has end-stage arthritic changes of the ankle and subtalar joints. C and D, Postoperative views.

A Kirschner wire is inserted through the calcaneus and into the central aspect of the tibia. A wire inserted off center will result in malreduction of the joint during insertion of the nail. For example, if the wire hits the anterior cortex and bends, reaming the calcaneus and talus in this position will result in a greater degree of flexion than was anticipated. Similarly, extension will occur if the wire hits the posterior cortex.

Some nails have a bend on the distal end that allows more lateral placement of the starting point in the calcaneus, potentially improving calcaneal fixation. Nail designs vary by the fixation achieved (i.e., lateral versus lateral and posterior screw fixation on the distal end), length (i.e., 150 to 300 mm), and compression techniques.

The tibia should be sequentially reamed until appropriate cortical chatter is obtained. The nail is sized for 1 mm less than the last reamer diameter. The reamer should be passed beyond the planned length of the nail to ensure that the nail does not bind in the tibia before being fully seated.

The surgeon should ensure that there is no stress riser at the tip of the nail. Occasionally, the drill for the proximal locking screw passes posterior to the nail and creates a stress riser. In this case, a longer nail should be used to bypass the stress riser.

The retrograde nail should be correctly seated to ensure that the distal locking screws are correctly located within the talus and calcaneus. Compression may be achieved through the fusion site by dynamic proximal fixation. Distal fixation can be performed first, the nail impacted, and then proximal fixation performed. Alternatively, proximal fixation can be achieved first and then distal compression performed on the nail or using an external compression device. Regardless of the sequence, the surgeon should perform some form of compression and should understand the nail system being used. Compression should be performed across the ankle first, followed by the subtalar joint. Failure to compress the joint may result in nonunion. Additional fixation using compression screws around the nail can be performed if the surgeon thinks that additional fixation is required.

Fluoroscopic views are obtained at the end of the procedure. The wounds are closed, and the patient is immobilized during the postoperative period.

Instrumentation

The 1.9-mm-diameter arthroscope is best for the triple fusion because the joint capsules are tight. However, the fluid flow is inadequate for using the smaller arthroscope and canula for the débridement for this type of fusion, and a separate portal for inflow may be required.

The 3.5-mm or smaller shavers can be used. May colleagues and I used a small joint distractor in some of the earlier cases but have preferred no distraction for the more recent cases, because this allows easier motion around the joints, as recommended by Lui.²

Technique

The patient is positioned with the operative hip internally rotated on a beanbag or elevated on a bump. The leg is prepared and draped free.²

Talonavicular Fusion.

The talonavicular joint is best approached from a dorsal medial, plantar medial, and dorsal lateral portal. A trans-calcaneocuboid joint portal can assist in visualization of the plantar lateral aspect of the joint (Figs. 19-5 and 19-6).

FIGURE 19-5 A cadaver view of the calcaneocuboid and talonavicular joints shows the position of the portals (arrows).

FIGURE 19-6 A trans-talonavicular portal can be used for the calcaneocuboid joint. Similarly, the talonavicular joint can be scoped from the calcaneocuboid joint.

Care should be taken not to damage the deep branch of the peroneal nerve that is closely apposed to the dorsal capsule of the joint. Palpation of the dorsalis pedis artery before inflation of the tourniquet should assist the surgeon in its correct localization. Confirmation of the position of the cannula by intraoperative fluoroscopy is required, particularly in patients with softer bone (Fig. 19-7).

FIGURE 19-7 The arthroscopic view shows the talonavicular joint. In this case, a small external fixator was used to assist in distraction.

The arthritic and mobile rheumatoid joint is quite easily instrumented and often requires minimal débridement. When the joint is hard to distract, cautious release of the capsule with a meniscectomy knife may be required. If the joint is stiff, it may be hard to identify. Fluoroscopic confirmation of correct positioning of the cannula is wise, because inadvertent insertion of the cannula into an osteopenic navicular in an arthritic patient can occur. If required, the portal can be expanded to 1 cm, and skin hooks can be used to retract while the joint capsule is released under direct visualization. Alternatively, after the joint is initially visualized, the joint capsule can be released using a meniscectomy blade or small osteotome under direct visualization.

An alternative technique uses a cannulated drill placed across the arthritic joint. The 5-mm drill from the cannulated hip screw set has a diameter to fit the 2.9-mm scope and canula. After the guidewire is placed under fluoroscopic control, the drill is placed across the joint under direct fluoroscopy (Fig. 19-8). Oblique drill placement is used. One drill hole can then be used for the scope and the other for the instruments. However, working outside these drill holes can be problematic for completing cartilage removal. Similarly, tight subtalar and calcaneocuboid joints can be drilled with a cannulated drill to facilitate exposure (Fig. 19-9).

FIGURE 19-8 A cannulated drill is used to expose the talonavicular joint.

FIGURE 19-9 A cannulated drill is used to expose the subtalar joint.

Fixation

Fixation of the arthroscopic triple arthrodesis follows the same screw placement as for the open procedure. Cannulated or solid screws can be used, depending on surgeon’s preference (Fig. 19-10).

FIGURE 19-10 Preoperative (A and B) and postoperative views (C and D) of an arthroscopic triple arthrodesis.

The subtalar fusion can be transfixed using two screws from the calcaneus into the talus. Care should be taken to ensure that the screws are within the body of the talus and not laterally placed. The starting point in the calcaneal tuberosity needs to be at the midpoint of the tuberosity or lateral to it to avoid medial penetration of the calcaneus and potential damage to the tibial nerve. Radiographs should include anteroposterior and lateral views of the foot, an anteroposterior view of the ankle, and an axial view of the calcaneus.

Fixation of the talonavicular joint can be performed percutaneously. Small fragment screws are used in all but the largest patients. A cannulated equivalent can also be used. The screws can be inserted from the tuberosity of the navicular, which is easy to palpate. The screws also can be inserted from the dorsomedial and dorsolateral side. Care should be taken to avoid the direct dorsal approach because the deep branch of the peroneal nerve may be injured. The screws must be placed parallel to the plantar surface of the foot to ensure that they engage the talus. Two or three screws should be used on the talonavicular joint.

Fixation of the calcaneocuboid joint can be obtained by a small incision in the sinus tarsi, just behind the anterior process of the calcaneus. The fixation proceeds from just behind the anterior process into the body of the calcaneus. Care should be taken to ensure that the screws are pointing laterally and dorsally enough to engage the cuboid. Two screws are used, with an additional third screw inserted percutaneously from the cuboid into the calcaneus.