Arthroscopy of the Foot and Ankle

Arthroscopy was first performed in 1918 by Takagi in Tokyo when he inspected a cadaver knee with a cystoscope.³²⁶ This eventually led to the development of a 7.3-mm arthroscope in 1920 and a 3.5-mm arthroscope in 1931. Kreuscher became the first American to report the use of an arthroscope in the knee joint in 1925.²³² In 1931, Burman⁶⁶ reported his experience of arthroscopic examination of multiple joints in a cadaver. At that time, the ankle was not believed suitable for arthroscopic examination because the joint space was too narrow.

In 1939, Takagi ⁴²² developed a standard method of arthroscopic examination of the ankle that was published in the Journal of the Japanese Orthopedic Association. In 1972, Watanabe⁴⁷¹ reported on 28 ankle arthroscopies performed with the newly developed fiberoptic arthroscope. In this report, the anteromedial, anterolateral, and posterior approaches to the ankle during arthroscopic examination were described in detail. In 1976, Chen⁸² reported his experience with ankle arthroscopy in 67 clinical and 17 cadaver cases. In this report, Chen offered an extensive description and discussion of the compartments within the ankle and their surgical anatomy. More recently, Andrews, Boynton, Drez, Guhl, Ferkel, Jerosch, Ogilvie-Harris, van Dijk, and Parisien have described their techniques and approaches for arthroscopy of the ankle joint.*

Since 1980, clinical experience with ankle and foot arthroscopy has significantly increased. Arthroscopy will continue to be an important diagnostic and therapeutic technique for documenting and treating disorders of the ankle and foot. Arthroscopic techniques have continued to advance with the development of small-joint arthroscopes and instrumentation that have allowed improved visualization and surgical access to the foot and ankle.

Advantages and Disadvantages

Arthroscopy of the ankle and foot allows direct visualization of all intraarticular structures without an extensive surgical approach, arthrotomy, or malleolar osteotomy. Direct inspection of the ankle provides the best assessment of articular surface changes and damage. Ligamentous structures may be observed directly by using the arthroscopic approach. Intraoperative stress-testing maneuvers can be performed to determine the specific sites of laxity or incompetence of the ligamentous structures.

A plethora of surgical procedures can be performed by using arthroscopic techniques, including biopsy, debridement, synovectomy, loose body removal, and cartilage procedures. The potential postoperative advantages of arthroscopy include decreased patient discomfort and morbidity as well as faster rehabilitation, leading to an earlier return to daily and athletic activities.

Cartilage and soft tissue injuries of the ankle may be associated with recurrent effusion, nonspecific tenderness, restricted range of motion, popping, or a feeling of instability. These findings can pose a diagnostic challenge for the orthopaedic surgeon. Arthroscopic examination of the ankle and foot provides the opportunity to directly visualize and evaluate articular cartilage and soft tissue pathology.

Disadvantages of ankle and foot arthroscopy are similar to those for arthroscopy of other joints. These include the steep learning curve, the potential for numerous complications, the need for special equipment and operating team, a propensity for equipment failure, and expense.

Indications and Contraindications

Ankle arthroscopy has numerous indications (Table 32-1). The relative contraindications for ankle and foot arthroscopy include moderate degenerative joint disease with restricted range of motion, a significantly reduced joint space, severe edema, tenuous vascular status, and complex regional pain syndrome.

Table 32-1

Indications for Ankle Arthroscopy

Soft tissue injury and impingement

Biopsy of intraarticular soft tissues

Loose Bodies

Osteophytes

Tendinitis

End-stage arthritis requiring fusion

Unexplained pain/swelling

Mechanical symptoms (locking, catching, painful popping)

Osteochondral Injuries

The absolute contraindications include localized soft tissue infection, severe degenerative joint disease not amenable to arthroscopic arthrodesis, and other generalized medical conditions precluding surgical intervention. In degenerative joint disease, it is often difficult to achieve successful joint distraction and adequate range of motion for arthroscopic visualization of the joint. In the case of localized soft tissue infection, there is a potential for intraarticular dissemination and thus septic arthritis. Arthroscopy may be an excellent diagnostic and treatment option in the setting of septic arthritis without extension into the soft tissue envelope.418,467

Equipment

Arthroscope

The 1.9- and 2.7-mm video arthroscopes are used for ankle arthroscopy (Fig. 32-1). Rarely, the 4.0-mm arthroscope is used; however, the authors do not routinely recommend its use because its larger size prevents safe maneuverability within the joint. In general, the 4.0-mm arthroscope provides a large, clear picture and is more resistant to bending or breakage. Although the 2.7- and 1.9-mm short video arthroscopes are more delicate, they provide an excellent picture and a wide-angle field of vision. They are also preferred because the shorter lever arm reduces iatrogenic cartilage injury or instrument breakage.

Figure 32-1 Small-joint video arthroscopes. Top, 1.9-mm arthroscope and cannulas with and without side portals. Middle, 30-degree 2.7-mm arthroscope with cannulas. Bottom, 70-degree 2.7-mm arthroscope. Each arthroscope screws directly into the camera.

A videoscope has a telescopic extension that is directly connected to a camera without an intermediary eyepiece. This accommodates a camera that is lightweight, is easy to maneuver, and generates less torque because of its short lever-arm.

Arthroscopes provide excellent visualization throughout the ankle, particularly in the tighter spots, such as the medial and lateral gutters and posterior aspect of the ankle. The 1.9- and 2.7-mm arthroscopes have a 30-degree obliquity for improved field of vision. The 2.7- and 4.0-mm 70-degree arthroscopes are particularly helpful in seeing over the medial or lateral domes of the talus and looking into the gutters as well as evaluating certain osteochondral lesions of the talus. Surgeons must be cautious with use of 70-degree arthroscopes because they are not commonly used. The 70-degree arthroscopes have a central blind spot, making it more challenging to safely navigate the joint without causing iatrogenic cartilage injury.¹²³

For the extremely tight ankle, a 1.9-mm 30-degree arthroscope allows increased maneuverability. The small size of the 1.9-mm arthroscope decreases the amount of instrument crowding and inadvertent chondral damage. However, the 1.9- and 2.7-mm arthroscopes carry a higher risk of equipment failure because of their propensity to bend and break.

Regardless of the arthroscope used, it is important to have an interchangeable cannula system that allows the arthroscope and equipment to be switched from portal to portal without constant reinstrumentation of the portals (see Fig. 32-1). This minimizes the potential for nerve and wound damage. The cannula size for the 2.7-mm arthroscope is 2.9 mm, and for the 1.9-mm arthroscope, it is 2.1 mm.

Instruments

Although standard-size instruments can be used for ankle arthroscopy, small-joint instruments are preferred. These instruments are easier to maneuver within the tight joint spaces and are much more efficient to use than larger ones. Instruments typically used include the 2.0-, 2.9-, and 3.5-mm shavers and burrs; 3.5- and 4.5-mm ring and cup curettes; 1.5-mm probes; 2.9- and 3.5-mm graspers and baskets; 2.9-mm osteotomes; and pituitary rongeurs, microfracture picks, and banana blades (Fig. 32-2 and Table 32-2).

Table 32-2

Instrumentation Used in Ankle and Foot Arthroscopy

30- and 70-degree 2.7-mm arthroscopes and a 30-degree 1.9-mm arthroscope

3 three-chip cameras with cords

Compatible light source

High-definition monitor with digital image-capture system

Thigh holder

Noninvasive ankle distractor

Disposable soft tissue distractor strap

Adjustable intravenous (IV) poles for gravity fluid management

Small-joint shaver system

2.9-mm full-radius disposable blade, 2.9-mm barrel abrader, 3.5-mm incisor blade, and 3.5-mm abrader

Skin marking pen and ruler

No. 11 scalpel and mosquito clamp

22-gauge 1.5-inch needle

18-gauge spinal needle

Two 19-gauge 1.5-inch needles

10-mL syringe with IV extension tubing

Two 50-mL syringes

Small-joint instrumentation set with tray

Power reamer with Jacobs chuck and key

Wire driver (power)

0.045- and 0.062-inch Kirschner wires (smooth with trochar tips)

2.7- and 1.9-mm cannulas and trochars

Small-joint banana blade

Micro Vector drill guide system

Mallet

IV extension tubing

Figure 32-2 Essential arthroscopy equipment. A, Suction punch, rongeurs, and graspers. B, Freer, microfracture picks, curettes, ringed curettes, and probe. C, Micro Vector drill guide. D, A special small-joint tray has been developed, and all instruments are color coded according to type. (Courtesy Smith & Nephew Endoscopy.)

Ankle Distractors

An ankle distractor can significantly improve ankle visualization by increasing the space between the tibia and the talus. Without the distractor, certain areas of the ankle, such as the central tibial plafond and talar dome, the posterior inferior tibiofibular ligament, transverse ligament, and flexor hallucis longus (FHL), are poorly seen.

Distraction methods applied to the ankle may be either noninvasive or invasive (Fig. 32-3).* Noninvasive techniques include manual distraction and gravity distraction, which are uncontrolled methods. Other types of noninvasive methods, such as the modified clove-hitch knot around the ankle, are semicontrolled. Several controlled devices allow the ankle to be distracted noninvasively while also permitting the amount of pressure and force to be monitored and maintained mechanically (Fig. 32-4A). To minimize the potential for nerve injury, Dowdy et al¹⁰⁴ have recommended limiting the distraction force to less than 30 pounds for less than 1 hour when using noninvasive distraction.Invasive distractors are also available that use pins in the tibia and talus or calcaneus to provide mechanical distraction (Fig. 32-4B). Some of these devices have a strain gauge to measure the amount of force and permit some degree of freedom within the ankle joint. These have fallen out of favor in recent years because of risks of neurovascular injury, infection, fractures, scarring, and wound issues. In addition, the amount of distraction obtained is very similar with the noninvasive and invasive distractors.

Figure 32-3 Lateral views of ankle during arthroscopic examination. A, Without distraction. B, With controlled, noninvasive distraction device. C, With invasive distraction device.

Figure 32-4 Ankle distraction techniques. A, Soft tissue distraction strap attached to table with sterile clamp attached to side rail. B, Invasive distractor in place with pins in tibia and calcaneus.

Contraindications for noninvasive and invasive distraction include complex regional pain syndrome and open tibial epiphysis. Invasive distraction should also be avoided in patients with pyarthrosis or chronic infection and in high-performance athletes who need to return to their sport quickly.¹⁷⁹ Pins should be inserted unicortically to reduce the risk of fracture.

Over the last 15 years, the authors have used noninvasive distraction (see Fig. 32-4A) without significant complications and have not had to use invasive pins for any cases in the supine position.

Positioning and Preparation

Several positions are described in the literature.¹⁸⁷ The three most common include supine, lateral decubitus on a bean bag,³⁴⁷ and prone.^404,458 Some surgeons prefer the supine position, with the thigh secured by a nonsterile thigh holder as is commonly used with knee arthroscopy, to flex the knee 90 degrees over the end of the table.¹⁵ An alternative method is to use a urology leg holder positioned in the popliteal fossa; however, the surgeon must be very careful to keep the pressure in this area to a minimum. The chapter authors prefer the supine position with a special nonsterile thigh support (Fig. 32-5). The supine position is preferred for several reasons, including:

Figure 32-5 Author’s preferred positioning. A, The thigh is supported by a well-padded holder attached via a clamp to the rail of the table. A tourniquet is placed around the proximal thigh. The nonoperative extremity is well padded and kept straight on the table. B, The ankle is oriented in a neutral position by internally rotating the pelvis against a side post at the level of the greater trochanter.

Almost all procedures can be performed in a supine position

Ease of access to anterior and posterior portals

Adequate posterior access may still be achieved

Difficulty in arthroscoping both the tibiotalar and subtalar joints with patient prone without repositioning

A tourniquet is applied on the proximal thigh, and the thigh holder is placed superior to the popliteal fossa to keep the popliteal fossa free from pressure. It is used at the surgeon’s discretion. The thigh holder must be well padded to prevent injury to the sciatic nerve and is set to flex the hip at approximately 45 to 50 degrees. The operating table foot pad is removed to provide more room for posterior ankle access.

Because the thigh support is nonsterile, it should be applied before preparing the leg. A thigh post is positioned over the greater trochanteric region to help facilitate and maintain proper foot and ankle position and prevent hip external rotation. The patient is rotated internally to position the knee and ankle in a neutral orientation so that they both face straight up. With this setup, the surgeon can sit or stand during surgery, and both the anterior and posterior portions of the ankle are easily accessible without further manipulation of the patient’s extremity. The nonoperative lower extremity is placed on a well-padded, fully extended table and secured. Special care should be taken to pad all areas of bony prominence to prevent potential neurovascular compromise secondary to pressure. The patient is then prepared and draped in the standard fashion.

Table 32-3

Arthroscopic Portal Landmarks and Structures at Risk

Portal Site	Landmarks	Structures at Risk
Anteromedial	Medial to anterior tibialis tendon	Saphenous vein and nerve Anterior tibialis tendon EHL
Anterolateral	Lateral to peroneus tertius tendon	Superficial peroneal nerve EDC Peroneus tertius
Anterocentral	Between tendons of EDC	Dorsalis pedis artery Deep branches of peroneal nerve Medial branches of superficial peroneal nerve EDC
Medial midline	Between EHL and anterior tibialis tendon	Superficial peroneal nerve Deep peroneal nerve Dorsalis pedis artery EHL Anterior tibialis tendon
Posterolateral	Lateral to Achilles tendon	Branches of sural nerve Small saphenous vein
Posterocentral (trans-Achilles)	Through center of Achilles tendon	Achilles tendon
Posteromedial	Medial to Achilles tendon	Posterior tibial artery Tibial nerve Calcaneal branches of tibial nerve FHL tendon FDL tendon
Transmalleolar		Medially: Saphenous vein and nerve Tarsal tunnel contents (if posteromedial, see above) Laterally: Peroneal tendons Peroneus tertius Superficial peroneal nerve Sural nerve
Transtalar		Medially: Saphenous vein and nerve Laterally: Extensor tendons Superficial peroneal nerve Tarsal tunnel contents Saphenous vein

EDC, extensor digitorum communis; EHL, extensor hallucis longus; FDL, flexor digitorum longus; FHL, flexor hallucis longus.

Anterior Portals

The three most commonly used anterior portals are the anteromedial, anterolateral, and anterocentral (Fig. 32-6). The anteromedial portal is placed just medial to the anterior tibial tendon at the joint line. Care must be taken to not injure the saphenous vein and nerve traversing the ankle joint along the anterior edge of the medial malleolus.

Figure 32-6 Three anterior portals used for ankle arthroscopy. The anterocentral portal is rarely used.

The anterolateral portal is placed just lateral to the peroneus tertius tendon. This is at a level at or slightly proximal to the joint line. Care must be taken to avoid injury to the superficial peroneal nerve, which is the most commonly injured nerve during ankle arthroscopy. The superficial peroneal nerve divides approximately 6.5 cm proximal to the tip of the fibula into the intermediate and medial dorsal cutaneous branches.⁵ The intermediate dorsal cutaneous nerve passes over the inferior extensor retinaculum, crosses the common extensor tendons of the fourth and fifth digits, and then runs in the direction of the third metatarsal space before dividing into dorsal digital branches. The medial terminal branch of the superficial peroneal nerve—the medial dorsal cutaneous nerve—passes over the anterior aspect of the ankle overlying the common extensor tendons. It runs parallel to the extensor hallucis longus (EHL) tendon and divides distal to the inferior extensor retinaculum into the three dorsal digital branches.

Between these portals, an anterocentral portal may be established between the tendons of the extensor digitorum communis (EDC). This portal is placed between tendons of the EDC to avoid possible injury to the nearby neurovascular structures, including the dorsalis pedis artery and the deep branch of the peroneal nerve. The dorsalis pedis artery and the deep branch of the peroneal nerve lie deep in the interval between the EHL and the medial border of the EDC tendons. Medial branches of the superficial peroneal nerve must also be avoided when using this portal. Use of this portal is uncommon and rarely necessary, and the authors strongly discourage its routine use because of the increased potential for complications, including trauma to the dorsalis pedis artery.123,282,328,379

A medial midline portal has been described between the tendons of the EHL and anterior tibialis tendon.⁶² A study found this portal to be farther from the superficial peroneal nerve branches and the dorsalis pedis artery than the anterocentral portal. The chapter authors advocate the use of the anteromedial and anterolateral portals because they afford the most visualization and utility in ankle arthroscopy while minimizing potential complications.

Accessory anteromedial and anterolateral portals can be made over the medial and lateral talar dome to facilitate the treatment of specific lesions. These are most commonly used when working in the tight confines of the medial or lateral gutters. The accessory anteromedial portal is established 0.5 to 1.0 cm inferior and 1 cm anterior to the anterior border of the medial malleolus. It is especially useful in facilitating the evaluation of the deltoid ligament, particularly for removal of ossicles adherent to the deep portion of the ligament. The accessory anterolateral portal is established 1 cm anterior to and at, or just below, the tip of the anterior border of the lateral malleolus, near the anterior talofibular ligament.

Posterior Portals

Posterior portals are also useful during arthroscopy of the ankle (Fig. 32-7). These portals are commonly placed directly medial to, lateral to, or traversing the Achilles tendon, just distal to or at the joint line. The posterolateral portal is established in the soft spot just lateral to the Achilles tendon, 1.2 cm (0.5 inch) above the tip of the fibula.^{135,215,216,293} Branches of the sural nerve and the small saphenous vein must be avoided with the posterolateral approach.^2,119,404 It is the most commonly used and safest of the posterior portals.

Figure 32-7 Three posterior portals used for ankle arthroscopy. The posterolateral portal is the most often used.

The trans-Achilles portal is established at the same level as the posterolateral portal but through the center of the Achilles tendon. In the authors’ experience, this portal does not allow easy mobility of the instruments and may lead to increased iatrogenic damage to the Achilles tendon. For these reasons, the authors recommend against its routine use.

Several authors have discussed the merits of the posteromedial portal, which is made just medial to the Achilles tendon at the joint line.2,252,404 With the posteromedial portal, the tendons of the FHL and flexor digitorum longus (FDL) must also be protected. In addition, the posterior tibial artery and the tibial nerve with its branches must be avoided. The calcaneal nerve branches from the tibial nerve proximal to the ankle joint and traverses the interval between the tibial nerve and the medial border of the Achilles tendon.²⁸⁷ Because of the potential for serious complications and difficulty in maneuvering the arthroscope, the trans-Achilles and posteromedial portals are rarely used during supine arthroscopy but are routinely used during prone arthroscopy, which will be discussed in detail later in this chapter. On occasion, accessory posteromedial or posterolateral portals are used to facilitate treatment, especially for posterior osteochondral lesions of the talus (OLT).

Preferred Portals

During surgery, the anterolateral, anteromedial, and posterolateral portals are routinely used. On occasion, the accessory posteromedial portal is used between the posterior tibial tendon and flexor digitorum longus to treat very posteromedial osteochondral lesions. The transmalleolar portals ¹⁵⁵ are also occasionally used for operative techniques, particularly for drilling of Kirschner wires under fluoroscopic and endoscopic control through either the tibia or fibula into the talar dome, for the purpose of establishing new vascularity into an osteochondral lesion. Transtalar portals can also be used for drilling and possibly bone grafting osteochondral lesions of the talus.¹²³ Prone portals will be discussed later in the Hindfoot Arthroscopy and Endoscopy in the Prone Position section.

Portal Complications

There are several reports of neurovascular injury secondary to portal placement.* Ferkel et al¹²⁸ reported that neurologic injuries made up nearly half (49%) of all ankle arthroscopy complications, with the superficial peroneal most commonly injured, followed by the sural, saphenous, and deep peroneal nerves. All injuries were attributed to portal or distractor pin placement.

The anterocentral and posteromedial portals place the superficial and deep peroneal nerves and dorsalis pedis artery at increased risk.128,282,328,379,424 Because of the challenges in achieving adequate direct visualization of the posterior anatomy in the supine position, the posterior tibial nerve, posterior tibial artery, and calcaneal nerve may be at risk when a posteromedial portal is placed.^119,465 Amendola et al¹¹ proposed placing the patient prone when using posteromedial and posterolateral portals to reduce the risk of neurovascular injury. Acevedo et al² have recommended coaxial posterior portals. The posterolateral portal is placed first, posterior to the peroneal tendons, followed by the posteromedial portal. This latter portal is placed using an inside-out technique behind the medial malleolus and adjacent to the posterior tibial tendon. Injury to the ligaments and tendons can be prevented by using meticulous placement of the portals and avoiding overdistraction. The posterior portals are discussed later in the prone arthroscopy section.

Wound complications can be minimized through careful surgical technique. The use of interchangeable cannulas can minimize the trauma associated with the passage of instruments. Portal closure with a nonabsorbable vertical mattress suture, application of a compressive dressings, and postoperative immobilization in a well-padded splint can further decrease wound complications.

Surgical Technique

Normal Ankle Arthroscopic Anatomy

The intraarticular ankle anatomy during the arthroscopic examination has been described extensively by Chen.⁸² Drez et al¹⁰⁵ have divided the ankle joint into an anterior and a posterior cavity, each of which is subdivided further into three compartments for a methodical inspection of the joint. The chapter authors have devised a 21-point systematic examination (Table 32-4) of the anterior and posterior ankle joint that increases accuracy and reproducibility of the arthroscopic examination.^133,410,411

Table 32-4

Twenty-one–Point Ankle Arthroscopic Examination

FHL, flexor hallucis longus.

Examination of the Ankle (Video Clip 37)

As with other joints, it is imperative to use a methodical, systematic approach during arthroscopic examination of the ankle. This allows the surgeon to document the arthroscopic findings in a reproducible fashion, to accurately diagnose any potential intraarticular pathology, and to improve the quality of future clinical studies of the ankle arthroscopy patient population. The 21-point examination consists of three phases: the eight-point anterior examination, the six-point central examination, and the seven-point posterior examination.

The eight-point anterior examination (Fig. 32-8) includes the deltoid ligament, medial gutter, medial talus, central talus, lateral talus, talofibular articulation (trifurcation of the talus, tibia, and fibula), lateral gutter, and anterior gutter.

Figure 32-8 Eight-point anterior ankle examination through the arthroscope.

The six-point central examination (Fig. 32-9) is performed by maneuvering the arthroscope through the notch of Harty. The notch of Harty is an anatomic elevation of the anteromedial distal tibia. The central examination includes the medial central tibiotalus, middle tibiotalus, lateral tibiotalus, capsular reflection of the FHL tendon, transverse tibiofibular ligament, and posterior inferior tibiofibular ligament.