PATIENT POSITIONING

The patient is placed supine on the operating table with the hip and knee flexed and supported by a well-padded leg holder (Fig. 4-1). I prefer a leg holder with a long thigh segment and short knee segment to diffuse the distraction force over the wide area of the thigh rather than concentrating the force in the popliteal space and potentially causing obstruction to venous outflow. Sterile drapes are applied after skin preparation.

FIGURE 4-1 Position for ankle arthroscopy. The patient is supine, and the hip and knee are supported by a well-padded leg holder. The leg holder has a broad thigh support so that as distraction force is applied to the ankle, it is dissipated over a wide area of the thigh rather than concentrated in the popliteal fossa.

A sterile clamp is attached to the operating table side rail over the sheets, and a bar is fixed to the clamp. The noninvasive ankle distractor strap is placed around the hindfoot and midfoot and connected to the bar using a segment of sterile two-sided Velcro. This distraction setup allows the ankle and foot to rest in a plantigrade position while retaining the ability to move the ankle in dorsiflexion and plantar flexion intraoperatively (Fig. 4-2).

FIGURE 4-2 The leg is prepared and draped with sterile sheets, and the noninvasive distractor is applied to the ankle. The strap that is placed around the hindfoot and midfoot is attached to the bar using a strip of Velcro, with which the distraction force can be varied.

Invasive distraction is not required for standard ankle arthroscopy. It poses unnecessary risks to neurovascular structures, along with risks of infection and stress fracture.

Anatomic landmarks are then marked with a sterile marking pen. I outline the medial malleolus and the anterior joint line along with the contour of the distal fibula. Also marked are the position of the tibialis anterior tendon medially, the peroneus tertius tendon laterally, and the lateral border of the Achilles tendon posteriorly. The position of the superficial peroneal nerve branch passing over the anterolateral ankle can often be appreciated by plantar flexing and inverting the ankle.

PORTAL CREATION

Careful attention to portal creation technique can minimize the incidence of iatrogenic injury to neurovascular structures. The nick and spread technique is advised. Each portal is created by incising only the skin, avoiding penetration of the subcutaneous tissues with the knife blade. A small hemostat clamp is used to spread the subcutaneous tissues down to the level of the capsule. The capsule is penetrated using a blunt trocar to minimize the risk of iatrogenic articular cartilage injury.

The three standard working portals for ankle arthroscopy are the anteromedial portal, the anterolateral portal, and the posterolateral portal (Fig. 4-3). The anterocentral portal was used in the early days of ankle arthroscopy because of the purported benefit of increased visualization in the central compartment. However, this portal placement poses significant risk of injury to the deep peroneal nerve and the dorsalis pedis artery. The use of small joint arthroscopes and noninvasive joint distraction obviates the use of this portal for ankle arthroscopy.

FIGURE 4-3 Sketch showing the anatomy of the ankle in relation to the standard portals. A, The anteromedial portal is located immediately adjacent to the medial border of the tibialis anterior tendon at the level of the joint line. The anterolateral portal is located lateral to the lateral border or the peroneus tertius tendon. Accessory medial or lateral portals may be placed to approach the particular pathology found at surgery, and the location is guided using an 18-gauge needle intraoperatively. B, Posterolateral and posteromedial portal positions are shown in relation to significant anatomic structures.

The first portal created should be the anteromedial portal. In most patients, there is an indentation in the anteromedial articular surface of the distal tibia, known as the notch of Harty, that facilitates passage of instruments across the ankle joint from medial to lateral aspects. The surgeon palpates the tibialis anterior tendon and inserts an 18-gauge needle into the joint immediately adjacent to the tendon’s medial border (Fig. 4-4). As the needle enters the joint, the surgeon notices the sound of air entering the joint, which also allows the ankle to be distracted more easily. Needle placement is adjusted proximally or distally until the position that allows easiest passage across the joint is identified as the optimal location for the portal. The cannula is introduced through this portal, and the 2.7-mm arthroscope is introduced into the joint.

FIGURE 4-4 Each portal is located using an 18-gauge needle to determine the optimal position that allows easy passage of the instruments across the joint.

With the arthroscope in the anteromedial portal, the posterolateral portal is created under direct visualization. The portal is located adjacent to the lateral border of the Achilles tendon and approximately 1 to 2 cm distal to the anterior portal so that an upwardly angled 18-gauge needle passes into the joint beneath the posterior syndesmotic ligament complex and accommodates the posterior curvature of the talar dome (Fig. 4-5). Another 2.7-mm cannula is placed and functions as a dedicated inflow cannula attached to an arthroscopic fluid pump.

FIGURE 4-5 A, Intraoperative photograph shows the relative position of the posterolateral portal to the anterior portal. The posterolateral portal is approximately 1 to 2 cm distal to the level of the anterior portals and angled upward to accommodate the curvature of the talar dome. B, Cross-sectional sketch shows the anatomy of the ankle joint, which dictates the angle at which the posterior portal must be placed to accommodate the curvature of the talar dome.

Although inflow can be performed by gravity, the arthroscopic pump allows control over the inflow pressure and the maximum flow rate allowed by the pump. The surgeon must monitor the condition of the soft tissue of the calf frequently during the case to ensure that fluid extravasation does not result in excessive swelling.

The anterolateral portal is placed in a manner similar to placement of the anteromedial portal adjacent to the lateral border of the peroneus tertius. Careful attention to portal creation technique minimizes the risk of injury to branches of the superficial peroneal nerve, the most commonly injured nerve in ankle arthroscopy, which is always located close to the anterolateral portal. The arthroscopic view is directed laterally to visualize entry of the 18-gauge needle, ensuring optimal position as the needle is passed across the joint.

Accessory portals medially or laterally may be required in some circumstances, particularly if surgery is being performed deep in the medial or lateral gutters. Optimal location for these portals is identified using a needle, and as long as there is approximately 1 cm between the standard portal and the accessory portal, wound-healing problems should be minimal. The trans-Achilles tendon portal described in the early days of ankle arthroscopy is not necessary and poses unnecessary risks of injury to the tendon.

DIAGNOSTIC ARTHROSCOPY

Diagnostic ankle arthroscopy is initiated from the medial portal using a 2.7-mm, 30-degree arthroscope. A 70-degree arthroscope should be available to enhance visualization in the medial and lateral gutters or in the posterior joint when viewing from the anterior aspect. Almost all ankles can be instrumented using the 2.7-mm arthroscope, but a 1.9-mm backup arthroscope may be useful in a particularly tight joint.

Ferkel has emphasized the importance of an organized approach to diagnostic ankle arthroscopy with a 21-point examination that starts with the anteromedial approach, then uses the anterolateral approach, and concludes with direct posterior viewing from the posterolateral portal.⁷ Depending on the pathology, initial visualization of the joint may be impaired by hypertrophic synovium or bony exostoses, and limited débridement may be required at the start of the case. It is important to débride any hypertrophic synovium with a mechanical shaver, keeping the blade directed away from the relatively thin capsule of the anterior joint to avoid inadvertent injury to the anterior neurovascular structures while also avoiding injury to the joint surfaces. Bipolar intra-articular cautery facilitates hemostasis when performing the procedure without tourniquet inflation.

The tip of the medial malleolus is visualized from the anteromedial portal along with the deep deltoid ligament spanning the space between the malleolus and the talus (Fig. 4-6). A probe is introduced from the anterolateral portal to palpate structures with the arthroscope in the anteromedial portal. The surgeon then directs the arthroscope up the medial gutter (Fig. 4-7) and into the tibiotalar joint through the notch of Harty (Fig. 4-8). At this point, the arthroscope usually can be maneuvered in a posterolateral direction across the dome of the talus, affording visualization of the entire dome of the talus and the posterior joint structures (Fig. 4-9).

FIGURE 4-6 Arthroscopic view from the anteromedial portal shows the tip of the medial malleolus, the talus, and the fibers of the deltoid ligament.

FIGURE 4-7 Arthroscopic view from the anteromedial portal shows the medial gutter of the right ankle.

FIGURE 4-8 Arthroscopic view from the anteromedial portal shows the anteromedial dome of the talus in the foreground and the articular surface of the medial malleolus in a right ankle (dry joint).

FIGURE 4-9 Arthroscopic view from the anteromedial portal shows the midportion of the talar dome, the distal tibial articular surface above, and in the background, the inflow cannula entering the joint beneath the posterior syndesmotic ligaments.

The interosseous ligament complex is identified posteriorly (Fig. 4-10). These ligaments display a variable anatomy and have been described differently in anatomic dissection studies. Ferkel has described three major ligament components.⁸ Superiorly, the broad posterior-inferior tibiofibular ligament represents the most distal end of the syndesmosis and its most distal fibers can be seen intra-articularly as the most superior component of the complex coursing from superior and medial to inferior and lateral aspects. Beneath this ligament is the less robust transverse tibiofibular ligament, which attaches to the posterior fibular tubercle on the fibula and to the posterior portion of the distal tibial articular surface, spanning to the medial malleolus. The tibial slip is the most inferior of the posterior interosseous structures. Golano and colleagues have described the posterior ligament anatomy to include the posterior-inferior tibiofibular ligament, which is also called the tibial slip.⁹ The transverse ligament was defined as the deep component of the posterior-inferior tibiofibular ligament. The flexor hallucis longus tendon may be seen as a vertically oriented structure in the posterior ankle compartment when the capsule is thin, and this structure is made more prominent by flexing and extending the great toe.

FIGURE 4-10 Posterior syndesmotic ligaments include the posterior-inferior tibiofibular ligament (PITFL) and the transverse tibiofibular ligament (TTFL) of the right ankle.

Depending on the degree of inherent joint laxity, it may not be possible to maneuver the arthroscope directly across to the lateral side of the joint, but the lateral joint structures can be visualized by directing the arthroscope’s viewing angle laterally (Fig. 4-11). The structures to be identified are the lateral dome of the talus, the distal tibiofibular joint, and the soft tissues of the syndesmosis. The arthroscope is then gently withdrawn, revealing the anterior tibia, which should be carefully examined for the presence of bony exostosis (Fig. 4-12). The view of the anterior joint may be facilitated by decreasing the amount of joint distraction while dorsiflexing the ankle to allow the anterior capsule to distend. The arthroscope’s viewing angle is then directed along the neck of the talus to evaluate the capsular insertion on the talar neck (Fig. 4-13). As the arthroscope is directed laterally, the well-defined inferior fascicle of the anterior-inferior tibiofibular ligament is identified as a vertically oriented structure connecting the tibia and fibula (Fig. 4-14).

FIGURE 4-11 Lateral view from the anteromedial portal across the talar dome of the right ankle. The distal fibula is visible in the background, as is soft tissue in the tibiofibular syndesmosis.

FIGURE 4-12 Arthroscopic view from anteromedial portal shows the distal tibial articular surface of the right ankle.

FIGURE 4-13 Arthroscopic view from the anteromedial portal shows the talar neck of the right ankle.

FIGURE 4-14 Arthroscopic view from the anteromedial portal in the right ankle shows the distal tibiofibular articulation and the vertically oriented fibers of the anterior-inferior tibiofibular ligament (AITFL).

The arthroscope is directed into the lateral gutter and then down to the level of the tip of the lateral malleolus (Fig. 4-15). The anterior talofibular ligament can usually be defined starting from its origin on the anterior-inferior fibula and curving to insert on the talus.

FIGURE 4-15 Arthroscopic view from the anteromedial portal in the right ankle. The distal fibula and the adjacent articular surface of the talus are seen, along with the arching fibers of the anterior talofibular ligament (ATFL).

The arthroscope is then switched to the anterolateral portal, and a diagnostic examination is performed from this approach starting at the tip of the lateral malleolus, which can usually be viewed more completely from this approach. In addition to the anterior talofibular ligament, the entire articular surface of the lateral gutter is evaluated from this viewpoint, and the posterior talofibular ligament often can be seen at the posterior extent of the gutter. The arthroscope is then directed up the lateral gutter and into the anterolateral joint to visualize the syndesmosis, distal fibula, lateral tibia, and lateral dome of the talus. All structures visualized from the anteromedial portal are evaluated from the anterolateral perspective for complete assessment.

The final assessment of the joint is from the posterolateral approach, with the inflow and arthroscopic probe placed in one of the anterior portals. This view optimizes visualization of the posteromedial talar dome and may be especially useful for treatment of osteochondral lesions of the posteromedial talar dome, which may be difficult to appreciate fully from anterior approaches. In this circumstance, the lesion is viewed from the posterior portal, and instruments are introduced from the anterior portal. The posterior portal also affords excellent visualization of the deep deltoid ligament as the arthroscope is advanced from the posterior tip of the medial malleolus, up the medial gutter, and over the talar dome. The arthroscope is then directed horizontally along the posterior talar dome and beneath the posterior tibiofibular ligament complex. The more lateral aspect of the talar dome and the posterior talofibular articulation may be difficult to appreciate from the posterolateral portal, depending on the patient’s anatomy and area of penetration of the posterior cannula beneath the syndesmotic ligaments. A complete inspection of the posterior recess completes the examination.

SUBTALAR JOINT ARTHROSCOPY

Practical applications of arthroscopic techniques to the subtalar joint have been facilitated by the development of small-diameter, high-quality optics. Initial efforts to visualize this small, highly constrained joint with standard 4-mm arthroscopes had little success. However, the joint can be approached reliably using the 2.7- or 1.9-mm arthroscopes for diagnostic arthroscopy, along with an expanding list of indicated procedures that are outlined in later chapters. Refinement of the technique for posterior ankle and subtalar joint arthroscopy has expanded our ability to visualize the subtalar joint.

As in the ankle joint, the subtalar joint presents a complex, curved articular surface that is even more tightly held in position by ligaments, especially the stout talocalcaneal interosseous ligament. Application of mechanical distraction adds little to our ability to separate the articular surfaces because of these ligaments, and the procedure usually is performed without the distractor.

Standard subtalar arthroscopy is performed with the patient positioned supine on the operating table with a bump placed beneath the hip to create a semilateral position. There are three basic lateral portals for subtalar joint instrumentation. Alternatively, a patient undergoing ankle and subtalar joint arthroscopy may remain in the supine position with the hip and knee flexed and supported by the leg holder, as described for standard ankle arthroscopy.

The anterolateral portal is placed approximately in the soft spot of the sinus tarsi, about 2 cm anterior and 1 cm distal to the tip of the fibula (Fig. 4-16). The posterolateral portal is placed approximately 2 cm posterior and 1 cm proximal to the tip of the fibula, which is lateral to the border of the Achilles tendon. If the subtalar arthroscopy is performed after ankle joint arthroscopy, the posterolateral portal used for the ankle can be redirected into the subtalar joint. The central portal is located just distal and inferior to the lateral malleolus tip. This portal is immediately anterior to the peroneal tendon sheath.

FIGURE 4-16 Sketch shows the placement of standard portals for subtalar arthroscopy. The anteromedial portal is approximately 1 cm distal and 2 cm anterior to the tip of the fibula in the palpable sinus tarsi. The posterolateral portal is located approximately 1 cm proximal and 2 cm proximal to the tip of the fibula. The central portal is placed just anterior to the tip of the fibula and just anterior to the peroneal tendon sheath.

I find that arthroscopy of the subtalar joint is more reproducible if the portal locations are first confirmed using 18-gauge needles. A needle is introduced into the presumptive anterolateral portal. When correctly placed, this needle should pass easily in a posteromedial direction and is located just posterior to the talocalcaneal interosseous ligament. Another needle is placed into the posterolateral position, and saline is injected into one of the needles. Outflow of the saline through the other needle confirms appropriate position for the two portals.

The nick and spread technique is used to place 2.7-mm cannulas into the portals, and the arthroscope is introduced into the anterior portal to initiate diagnostic arthroscopy. The talocalcaneal interosseous ligament is identified by turning the viewing angle of the arthroscope to point in an anterior direction. After that ligament is identified, the arthroscope is turned to view posteriorly, and the joint line is followed into the lateral gutter. The central portal is then established under direct visualization by introducing an 18-gauge needle and confirming that the needle location affords optimal access to the joint surfaces.

The joint is examined from the anterior view while placing a probe into the central portal. The arthroscope is introduced posterior to the interosseous ligament and advanced as far medial as possible to visualize the deep portion of the ligament and medial articular surface of the posterior subtalar joint (Fig. 4-17). As the arthroscope is slowly withdrawn, the more superficial portion of the ligament and the anterolateral margin of the posterior subtalar joint are examined (Fig. 4-18). As the arthroscope is manipulated into the lateral gutter, rotating it for viewing and keeping the joint line visible as the corner is rounded, the lateral talocalcaneal ligament is the first ligament capsular condensation observed (Fig. 4-19). Proceeding slightly more posteriorly, the operator can see the location of the calcaneofibular ligament.

FIGURE 4-17 Arthroscopic view of right subtalar joint from anterolateral portal shows the talocalcaneal interosseus ligament (IL) on the right and the anterior portion of the posterior subtalar joint to the left.

FIGURE 4-18 Arthroscopic view of the right subtalar joint from the anterolateral portal.

FIGURE 4-19 Arthroscopic view of the right subtalar joint from the anterolateral portal shows the lateral gutter with the lateral talocalcaneal ligaments on the left.

In some joints, the arthroscope can be advanced from the anterolateral portal further into the lateral gutter to the posterolateral recess (Fig. 4-20). As the viewing angle is turned toward the joint, the articular surface of the posterior process of the talus, or the os trigonum if present, can be seen. Turning the viewing angle toward the capsule laterally reveals the posterior talocalcaneal ligament.

FIGURE 4-20 Arthroscopic view of the posterior extent of the right subtalar joint.

If the arthroscope cannot be advanced into the posterolateral recess from the anterolateral portal, the arthroscope is switched to the posterior portal to achieve visualization of the structures previously described. In a relatively lax ankle, the arthroscope can be advanced across the joint, and the interosseous ligament can be examined from this posterior view. The examination should start in the lateral gutter. The arthroscope then is withdrawn carefully as the posterolateral corner is rounded and the central and the medial aspects of the posterior subtalar joint are examined. If feasible, the arthroscope is advanced into the posteromedial gutter and then anteriorly to visualize as much of the medial articular surface as possible.

POSTERIOR ANKLE AND SUBTALAR ARTHROSCOPY

When the anticipated ankle or subtalar pathology is definitively localized to the posterior compartment, the joints may be assessed using a posterior approach. This approach was pioneered by van Dijk in the Netherlands. The procedure described subsequently is based on his report of posterior ankle arthroscopy.

The patient is placed prone on the operating table with the foot and ankle extended slightly past the end of the table and supported with a small bolster (Fig. 4-21). If distraction is necessary, a soft tissue distractor may be placed as for routine anterior arthroscopy and attached to the surgeon, who can apply traction when necessary by leaning backward. However, much posterior pathology can be approached without distraction, including os trigonum, posterior bony or soft tissue impingement, pathology of the flexor hallucis longus tendon, and posterior articular pathology of the talus or calcaneus.

FIGURE 4-21 Patient placement position for prone posterior ankle and subtalar joint arthroscopy.

Portals are placed immediately adjacent to the medial and lateral borders of the Achilles tendon at approximately the level of the tip of the fibula (Fig. 4-22). The nick and spread technique is used to avoid injury to superficial neurovascular structures. The standard 4-mm arthroscope can be used for posterior ankle arthroscopy.

FIGURE 4-22 Sketch shows the placement of standard posteromedial and posterolateral portals for posterior ankle and subtalar joint arthroscopy. The portals are placed approximately at the level of the tip of the fibula.

To visualize the posterior ankle joint, a space must be created in the area just posterior to the joint. Soft tissue (i.e., fatty tissue) must be débrided to create the space without causing injury to any other structures. The goal is to create a space and to visualize the flexor hallucis longus tendon. After the great toe flexor is visualized, safe dissection can be performed lateral to this tendon, avoiding injury to the posteromedial neurovascular structures that lie medial to the tendon. It is essential to use proper technique in the initial exposure.

The arthroscope cannula with a blunt trocar is introduced into the lateral portal and directed toward the great toe until bone is palpated. The arthroscope is introduced into this cannula. Inflow is placed under low-pressure and low-flow parameters, but there is no actual space in which to see; only the fat is visible immediately posterior to the joint. The 3.5-mm shaver is introduced from the medial portal at a perpendicular angle to the arthroscope, and it is advanced until it makes contact with the arthroscope’s cannula. The shaver is then directed along the cannula until it reaches the level of the arthroscope’s tip (Fig. 4-23). Initial shaving is performed with the open end of the shaver directed laterally and the viewing angle of the arthroscope directed medially. In this fashion, the blade is less likely to be directed toward the flexor hallucis longus tendon and the neurovascular structures medial to it. With minimal shaving, a space is created, and the flexor hallucis longus is identified.

FIGURE 4-23 Sketch shows a cross-sectional view of the ankle, with the arthroscope in the posterolateral portal and the shaver in the posteromedial portal. The arthroscope cannula is placed in the direction of the first web space, and the shaver is directed perpendicular to the arthroscope cannula until it makes contact with it. The shaver is then guided along the shaft of the arthroscope cannula to the tip. A space is created by resecting posterior fat with the shaver blade pointed laterally and the arthroscope angled medially. Dissection proceeds laterally after identifying the flexor hallucis longus tendon medially.

After the tendon is identified, it is protected from the surgical instruments, and all dissection is directed lateral to the tendon (Fig. 4-24). A capsulectomy is performed, revealing the ankle joint above and the subtalar joint below. The posterior process of the talus, or the os trigonum if present, is identified along with the attachment of the posterior talofibular ligament (Fig. 4-25). A bipolar electrocautery device is useful to achieve hemostasis and to perform accurate dissection of soft tissue from bone. Pathology in both joints can be addressed from this approach, and operative arthroscopy is described in Chapter ••.

FIGURE 4-24 Posterior ankle arthroscopy of the right ankle shows the flexor hallucis longus tendon (FHL) on the left and the ankle and subtalar joints on the right.

FIGURE 4-25 Posterior ankle arthroscopy shows the subtalar joint.

CONCLUSIONS

Diagnostic arthroscopy of the ankle joint can be routinely performed using small joint arthroscopes with noninvasive distraction. Standard portals include anteromedial, anterolateral, and posterolateral portals. A systematic process using each of the portals affords complete visualization of the joint and approaches for instrumentation and surgical procedures.

The subtalar joint can be examined from a lateral approach using three standard portals or from the direct posterior approach. Only the posterior subtalar joint is visualized in standard subtalar arthroscopy.

The posterior ankle and subtalar joints can be viewed from the direct posterior approach using the technique of van Dijk. This approach is particularly useful for the treatment of posterior ankle impingement, os trigonum syndrome, posterior osteochondral defects of the ankle and subtalar joint, and pathology involving the flexor hallucis longus tendon.