Porter & Schon: Baxter's The Foot and Ankle in Sport, 2nd ed.

Section 3 - Anatomic Disorders in Sports

Chapter 16 - Diagnostic and operative ankle and subtalar joint arthroscopy

  1. Niek van Dijk,P.A.J. deLeeuw,,
    Rover Krips


CHAPTER CONTENTS

  

 

History of the technique

  

 

Indications and contraindications

  

 

Surgical technique

  

 

Specific indications

  

 

References

  

 

Further reading

History of the technique

Arthroscopy has revolutionized the practice of orthopaedic surgery since the mid-1970s. After a long history of sporadic attempts at arthroscopy, technologic breakthroughs in Japan and several surgical pioneers in North America launched widespread interest in percutaneous joint surgery. Tagaki in 1939 described systematic arthroscopic assessment of the ankle joint.[1] Watanabe published a series of 28 ankle arthroscopies in 1972, followed by Chen in 1976.[2] In the 1980s, several publications followed. [0030] [0040] Over the last 15 years, arthroscopy of the ankle joint has become the most important diagnostic and therapeutic procedure for chronic and posttraumatic complaints of the ankle joint. Interest in ankle arthroscopy has increased steadily following successful clinical experience with arthroscopy of the knee and shoulder.[5] This rapid rise in the popularity of foot and ankle arthroscopy is partly because other noninvasive techniques cannot adequately diagnose disorders in these joints. To operate in the central and posterior ankle, some type of distraction device is needed. Invasive external distraction was tried in the early 1980s. A noninvasive technique was first described by Yates and Grana in 1988.[6] With the advent of better small-joint arthroscopes and instrumentation, and the production of more efficient noninvasive distraction devices, the development of tendoscopic surgery, and the introduction of a two portal technique for posterior ankle problems, ankle arthroscopy further developed to the current state. However, the dynamic nature of arthroscopy necessitates constant improvements that will continue to allow this field to grow. Ankle arthroscopy has become an integral part of modern orthopaedic surgery. Arthroscopic procedures can be used most successfully when practiced with a firm understanding of their subtle refinements, limitations, and risks.

 

Indications and contraindications

The key point in the assessment of ankle joint pathology is the clinical diagnosis. By means of a clinical diagnosis, an indication is set for an arthroscopic intervention. Furthermore, the clinical diagnosis is essential for preoperative planning.[7] The clinical diagnosis is based on history, symptoms and signs, and radiographic examination. Anterior problems include soft-tissue or bony impingement, synovitis, loose bodies, or ossicles. More centrally located complaints can originate from an osteochondral defect or arthrosis, whereas posterior problems can be caused by intra-articular pathology, such as posterior impingement syndrome (os trigonum); posttraumatic calcifications; loose bodies or synovitis; or by periarticular posterior ankle pathology, such as peroneal tendon, posterior tibial tendon, or flexor hallucis longus (FHL) pathology. In posterior ankle disorders, especially, differentiation from subtalar pathology is sometimes difficult.

The relative contraindications for ankle arthroscopy include moderate degenerative joint disease with restricted range of motion, a significantly reduced joint space, severe edema, and tenuous vascular status.[8] The absolute contraindications for ankle arthroscopy include absence of a clinical diagnosis, severe degenerative joint disease, and localized soft-tissue infection. However, if septic arthritis already is present, ankle arthroscopy is indicated, because it is a useful tool for drainage, debridement, and lavage of the joint.[9]

 

Surgical technique

Operative Setup

The procedure generally is carried out as outpatient surgery under general anesthesia or epidural anesthesia. Patients can be placed in various positions. Most surgeons prefer the supine position with slight elevation of the ipsilateral buttock. A tourniquet is placed around the upper thigh. The heel of the affected foot rests on the very end of the operating table, thus making it possible for the surgeon to fully dorsiflex the ankle by leaning against the sole of the patient's foot. For the treatment of posterior ankle problems, the patient is placed in prone position ( Fig. 16-1 ). A tourniquet is applied and a small support is placed under the lower leg, making it possible to move the ankle freely.

 
 

Figure 16-1  For posterior ankle arthroscopy, the patient is placed in prone position. A tourniquet is applied and a small support is placed under the lower leg, making it possible to move the ankle freely.

 

 

There are some important considerations in deciding whether to use dorsiflexion or traction for routine anterior ankle arthroscopy. When saline is introduced in the dorsiflexion position, the anterior working area “opens up” and any bony or soft-tissue impediment in front of the medial malleolus, in front of the lateral malleolus, at the talar neck, or at the distal tibia can be visualized and treated. For the treatment of anterior impingement lesions, synovitis, ossicles, and loose bodies, it therefore is beneficial to perform the procedure without distraction. In this dorsiflexed position, the talus is concealed in the joint, thereby protecting the cartilage from potential iatrogenic damage. Loose bodies usually are located in the anterior compartment of the ankle joint. Dorsiflexion creates an anterior working area and makes removal easy.[10] Distracting the joint makes it possible for the loose body to “fall” into the posterior aspect of the joint, thus making removal more difficult or impossible by an anterior approach. The same is true for the removal of ossicles and bony spurs by chisel or burr. Distraction of the joint results in tightening of the anterior capsule, thus making it more difficult to identify anterior osteophytes, ossicles, loose bodies, and soft-tissue impediments. Furthermore, when portals are created and instruments are introduced in the distracted position, this may result in iatrogenic cartilage damage at the talar dome.[7]

The main reason for inspection of the talar dome and tibial plafond is for treatment of an osteochondral defect. A clinical diagnosis must be established preoperatively using history, physical examination, and standard x-rays. In case of doubt about the existence or the exact location and size of a defect, a preoperative spiral computed tomography (CT) scan or magnetic resonance imaging (MRI) can be performed. Knowing the exact location of a defect makes it possible to decide preoperatively whether distraction will be necessary or whether the osteochondral defect can be approached in a forced plantarflexed position of the foot. In our experience, more than 90% of medial and lateral talar dome lesions can be treated in a hyperplantarflexed position.[7] Distraction may be beneficial when an osteochondral defect is located in the posterior part of the medial or lateral talar dome or tibial plafond or when a soft-tissue impediment, ossicles, or an impregnated loose body is located in the joint space between fibula and tibia (intrinsic syndesmotic area). [0110] [0120] For posterior ankle problems, for example an osteochondral defect in the posterior quarter of the talar dome or in the posterior part of the tibial plafond, two-portal posterior ankle arthroscopy is an important alternative ( Fig. 16-2 ).[13]

 
 

Figure 16-2  Two-portal posterior ankle arthroscopy is an important alternative for the treatment of posterior ankle problems.

 

 

Arthroscopic Equipment

A 4.0-mm and 2.7-mm arthroscope with 30-degrees obliquity can be used for ankle arthroscopy. The new small-diameter, short arthroscopes yield an excellent picture that is difficult to distinguish from a standard 4.0-mm scope. The small-diameter arthroscope sheet, however, cannot deliver the same amount of irrigation fluid per time as the standard sheet. This is an important drawback when motorized instruments are used because these cases must benefit from an adequate amount of irrigation fluid. For routine arthroscopic procedures such as anterior impingement syndrome, loose body removal, treatment of synovitis, and the vast majority of osteochondral defects, it is beneficial to use the 4.0-mm arthroscope. A 2.7-mm arthroscope should be reserved for the treatment of osteochondral defects of the posterior third of the talar dome (when not approached by a posterior ankle arthroscopy), pathology of the articular part of the tibiofibular joint, such as a soft-tissue impediment or impregnated ossicles or loose bodies, or other posterior ankle problems that are treated by an anterior approach. Use of a 2.7-mm scope usually necessitates the creation of a third posterolateral portal to maintain adequate flow in the joint.

Irrigation

Different fluids can be used for arthroscopic irrigation during ankle and foot arthroscopy. Lactated Ringer's is the most commonly used fluid because it is physiologically compatible with articular cartilage and is rapidly reabsorbed if extravasated from the joint. Glycine and normal saline also can be used. When a 4-mm arthroscope is used, gravity inflow usually is adequate if the fluid is introduced through the arthroscope sheet. When a 2.7-mm arthroscope is used, the gravity inflow should be introduced through a separate (posterolateral) cannula. An alternative is to use an arthroscopic pumping device.

Accessory Instruments

An 18-gauge spinal needle is used to distend the joint and to locate the anterolateral portal. The spinal needle allows precise positioning under direct vision of the portals. The probes used in ankle arthroscopy should be about 1.5mm in diameter to reach the small recesses of the gutters and to lift up under loose articular cartilage. An angled tip is desirable to touch over the dome-shaped talus and flat tibia. Another important instrument is the grasper. For the removal of small, loose bodies in soft tissue, a flat-tipped grasping forceps with fine teeth can be used. For larger loose bodies and soft-tissue fragments, a cup-shaped, jaw-grasping forceps with serrated edges can be used. Small-joint basket forceps with different tip designs help to remove soft-tissue and chondral fragments. Various small-joint curettes, either straight or curved, are available. These instruments are particularly valuable for removing osteochondral lesions and trimming of articular cartilage edges. Small-joint osteotomes and chisels are available to remove osteophytes and ossicles and can facilitate tissue elevation. Sometimes a small periosteal elevator can be useful. Motorized instruments can excise larger volumes of tissue than conventional hand instruments and suction it quickly out of the joint. They also can be used for debridement of large osteochondral defects. A power burr is useful for abrading or excising hard bone fragments. Holes can be drilled in the subchondral bone to enhance vascularization and to stimulate the repair process.

Portals for Anterior Ankle Arthroscopy

Portals provide an entry to visualize the structures of the ankle and foot. Proper portal placement is critical to performing good diagnostic and therapeutic arthroscopy.[14] If the portals are positioned improperly, visualization can be impaired, making diagnosis and treatment more difficult. Two primary portals are used in routine ankle arthroscopy: the anteromedial and anterolateral portals. The anteromedial portal always is made first because it is easy to access. This is especially true with the ankle in hyperdorsiflexion. The exact point of entry in this position is easily reproducible, and the risk of neurovascular damage is minimal. Accessory anterior portals are located just in front of the tip of the medial or lateral malleolus. Some authors recommend routine placement of posterior portals in ankle arthroscopy. In these cases, a posterolateral portal is recommended. Because of the potential for serious complications, most authors feel that the posteromedial portal is contraindicated when performing anterior ankle arthroscopy.[15]

Anteromedial Portal

The anteromedial portal is placed just medial to the anterior tibial tendon at the joint line ( Fig. 16-3 ). Care must be taken not to injure the saphenous vein and nerve transversing the ankle joint along the anterior edge of the medial malleolus. In the hyperdorsiflexed position, a local depression can be palpated. In the horizontal plane, this depression is located between the anterior tibial rim and the talus. The surgeon's palpating thumb first detects the interval in the horizontal plane and subsequently locates the vertical position. In the vertical position, the anterior tibial tendon is the landmark. One should palpate the anterior tibial in the dorsiflexed position. In this dorsiflexed position the anterior tibial tendon moves ±1cm lateral. The location of the anteromedial portal now can be marked onto the skin just medial from the anterior tibial tendon. By moving the ankle joint from the plantarflexed position to the dorsiflexed position, the talus can be felt to move in relation to the distal tibia. The surgeon's thumb gets locked into this “soft spot” in the hyperdorsiflexed position. A small longitudinal incision is made through the skin only just medial from the anterior tibial tendon. Blunt dissection is performed with a mosquito clamp through the subcutaneous layer and through the capsule into the ankle joint. With the ankle in the forced dorsiflexed position, cartilage damage is avoided. In this forced dorsiflexed position, the arthroscope shaft with the blunt trocar is introduced. When the trocar is felt to contact the underlying bony “joint line,” the shaft with the blunt trocar is gently pushed further into the anterior working area in front of the ankle joint toward the lateral side. The anterior compartment is irrigated and inspected. The next portal to make is the anterolateral portal.

 
 

Figure 16-3  Left ankle. The anteromedial portal is placed just medial to the anterior tibial tendon at the joint line. Care must be taken not to injure the saphenous vein and nerve transversing the ankle joint along the anterior edge of the medial malleolus.

 

 

Anterolateral Portal

The anterolateral portal is the second standard anterior portal. It is placed just lateral to the tendon of the peroneus tertius at or slightly proximal to the joint line ( Fig. 16-4 ). It is made under direct vision by introducing a spinal needle. In the horizontal plane, it is situated at the level of the joint line. In the vertical plane, the anterolateral portal is located lateral to the common extensor tendons and the peroneus tertius tendon. Care must be taken to avoid the superficial peroneal nerve because it runs subcutaneously. This subcutaneous nerve often can be palpated or visualized by placing the foot in forced hyperplantarflexion and supination. The lateral dorsocutaneous branch of the superficial peroneal nerve thus can be visualized. The intermediate dorsal cutaneous branch of the superficial peroneal nerve crosses the anterior aspect of the ankle joint superficial to the common extensor tendons. Damage to this branch can be avoided by staying lateral to the extensor tendons. Once the lateral branch is identified, its position can be marked with a marking pen on the skin.

 
 

Figure 16-4  Left ankle. The anterolateral portal is placed just lateral to the tendon of the peroneus tertius at or slightly above the joint line.

 

 

The location of the anterolateral portal may vary depending on the location of the lesion in the ankle joint. For the treatment of anteromedial ankle pathology, the anterolateral portal can be placed slightly above the level of the ankle joint and as close to the peroneal tertius tendon as possible. For the treatment of lateral pathology, the anterolateral portal is placed at the level of the joint line and more laterally. After a small skin incision has been made, the subcutaneous layer and capsule are divided bluntly with a mosquito clamp.

Accessory Inferior Anteromedial and Anterolateral Portals

The lateral accessory portal is placed just below the anterior talofibular ligament. After introduction of a spinal needle, a skin incision is made in line with the anterior talofibular ligament. The bladeknife can be introduced into the joint under direct vision. On the medial side (after locating the portal with the spinal needle), the incision is made in line with the fibers of the deltoid ligament. The knife can be introduced directly into the joint under direct vision.

Transtibial and Transmalleolar Portals

A transmalleolar portal may be used for debridement and drilling of lesions of the talar dome. It is used most often in combination with ankle distraction. A special guide facilitates the placement of the portal and of the Kirschner wires that are used to drill the defect. Transtibial or transmalleolar drilling with a guiding system is especially useful for tibial plafond lesions. For the treatment of talar dome lesions, the transmalleolar portal has the disadvantage of causing damage to the cartilage of the medial malleolus opposite the osteochondral talar defect and therefore is not recommended to perform on a routine basis.

Portals for Posterior and Subtalar Ankle Arthroscopy

The anatomic structures in the posterior ankle compartment are in close relation to each other. Operative treatment can use either a posterolateral or a posteromedial approach.[13] Both imply the risk of damaging neurovascular structures. Posterolaterally, branches of the sural nerve and the lesser saphenous vein are at risk; posteromedially, the neurovascular bundle and its branches are at risk. [0140] [0150]

Posterolateral Portal

The posterolateral portal is made at the level or slightly above the tip of the lateral malleolus, just lateral to the Achilles tendon ( Fig. 16-5, A ). After making a vertical stab incision, the subcutaneous layer is split by a mosquito clamp. The mosquito clamp is directed anteriorly, pointing in the direction of the interdigital webspace between the first and second toe ( Fig. 16-5, B ). When the tip of the clamp touches the bone, it is exchanged for a 4.5-mm arthroscope shaft with a blunt trocar pointing in the same direction. By palpating the bone in the sagittal plane, the level of the ankle joint and subtalar joint most often can be distinguished because the prominent posterior talar process can be felt as a posterior prominence between both joints. It is not necessary to enter either joint capsule. The blunt trocar is situated extra-articularly at the level of the ankle joint. The blunt trocar is exchanged for a 30-degree, 4.0-mm arthroscope. The direction of view is lateral to prevent damage to the lens system.

 

 

Figure 16-5  (A) Right ankle. The posterolateral portal is made level to or slightly above the tip of the lateral malleolus just anteriorly to the Achilles tendon. (B) Left ankle. The mosquito clamp is directed toward the first interdigital webspace.

 

 

Posteromedial Portal

This portal is made just medial to the Achilles tendon. In the horizontal plane, it is located at the same level as the posterolateral portal ( Fig. 16-6 ). After the skin incision has been made, a mosquito clamp is introduced and directed toward the toward the arthroscope shaft, which already was introduced through the posterolateral portal. When the mosquito clamp touches the shaft of the arthroscope, the shaft is used as a guide to travel anterior in the direction of the ankle joint. All the way, the mosquito clamp must touch the arthroscope shaft until the mosquito clamp touches the bone. The arthroscope is pulled slightly backward and slides over the tip of the mosquito clamp until the tip of the mosquito clamp comes to view. The clamp is used to spread the extra-articular soft tissue in front of the tip of the camera. In situations in which scar tissue or adhesions are present, the mosquito clamp is exchanged for a 5-mm, full-radius shaver.

 
 

Figure 16-6  Right ankle. The posteromedial portal is made just medial to the Achilles tendon. In the horizontal plane, it is located at the same level as the posterolateral portal.

 

 

The fatty tissue overlying the joint capsule can be partially removed. At the level of the ankle joint, the posterior tibiofibular ligaments and the posterior talofibular ligament can be recognized. After removal of the very thin joint capsule of the subtalar joint, the posterior compartment of the subtalar joint can be visualized. The posterior talar process can be freed of scar tissue, and the FHL tendon can be identified. The FHL is an important landmark to prevent damage to the more medially located neurovascular bundle ( Fig. 16-7 ).

 
 

Figure 16-7  Left ankle. After removal of the thin joint capsule, the posterior ankle and subtalar joint can be visualized. The posterior talar process can be freed of scar tissue and the flexor hallucis longus tendon can be identified. This is an important landmark to prevent damage to the more medially located neurovascular bundle.

 

 

On the medial side, the tip of the medial malleolus and the deep portion of the deltoid ligament can be visualized. By opening the joint capsule from inside out at the level of the medial malleolus, the tendon sheath of the posterior tibial tendon can be opened and the arthroscope can be introduced into the tendon sheath. The posterior tibial (PT) tendon can be inspected. The same procedure can be followed for the flexor digitorum longus (FDL) ( Fig. 16-8 ).

 
 

Figure 16-8  Right ankle. By opening the joint capsule from inside out at the level of the medial malleolus, the tendon sheath of the posterior tibial tendon can be opened and the scope can be introduced into the tendon sheath of the posterior tibial tendon. This patient has a tendinitis of the posterior tibial tendon, recognized by the increased vascularity on and around the tendon. Higher up, a vincula is identified. The direction of the view is from distal to proximal.

 

 

With application of manual distraction to the os calcis, the posterior compartment of the ankle opens up and the arthroscope and shaver can be introduced into the posterior ankle compartment. A total synovectomy and/or capsulectomy can be performed. The talar dome can be inspected over almost its entire surface, as can the complete tibial plafond. An osteochondral defect or subchondral cystic lesion can be identified, debrided, and drilled. The posterior syndesmotic ligaments are inspected and, if hypertrophic, partially resected.

Removal of a symptomatic os trigonum, a nonunion of a fracture of the posterior talar process, or a symptomatic large posterior talar prominence involves partial detachment of the posterior talofibular ligament and release of the flexor retinaculum, both of which attach to the posterior talar prominence, and removal of the scar tissue on the posterior talar process. Removal of the pathologic bony fragment can be done by reduction from medial to lateral with a burr or by use of a 4-mm osteotome or a small rasp. When using the osteotome it is important not to start too far anterior to prevent damage to the subtalar joint.

Release of the FHL involves detachment of the flexor retinaculum from the posterior talar process. Adhesions surrounding the flexor tendon can be removed. On the lateral side, the peroneal tendons can be inspected ( Fig. 16-9 ).

 
 

Figure 16-9  Left ankle. During posterior ankle arthroscopy, the peroneal tendons can be inspected on the lateral side.

 

 

When a tight and thickened crural fascia is present, this can hinder the free movement of instruments. It can be helpful to enlarge the hole in the fascia by means of a punch or shaver. Bleeding is controlled by electrocautery at the end of the procedure.

Arthroscopic Anatomy

The ankle joint can be divided into anterior and posterior cavities, each of which can then be subdivided further into three compartments for methodologic inspection of the ankle joint. Ferkel[15] developed a 21-point systematic examination ( Table 16-1 ) of the anterior, central, and posterior ankle joint to increase the accuracy and reproducibility of the arthroscopic examination. For posterior ankle problems, Van Dijk et al.[13] reported on a two-portal approach with the patient in the prone position, specifically for close visualization of the posterior compartment of the ankle and subtalar joint. He developed a 14-point systematic examination for the hindfoot and posterior ankle joint ( Table 16-2 ).


Table 16-1   -- The 21-Point Arthroscopic Examination of the Ankle

Anterior:

Deltoid ligament

Medial gutter

Medial talus

Central talus and overhang

Lateral talus

Trifurcation of the talus, tibia, and fibula

Lateral gutter

Anterior gutter

Central:

Medial tibia and talus

Central tibia and talus

Lateral tibiofibular or talofibular articulation

Posterior inferior tibiofibular ligament

Transverse ligament

Reflection of the flexor hallucis longus

Posterior:

Posteromedial gutter

Posteromedial talus

Posterocentral talus

Posterolateral talus

Posterior talofibular articulation

Posterolateral gutter

Posterior gutter

From Ferkel, Fischer 1996[15]

 

 

 


Table 16-2   -- The 14-Point Hindfoot Endoscopic Examination

1. Lateral talocalcaneal articulation

2. Flexor hallucis longus retinaculum

3. Flexor hallucis longus tendon

4. Posterior talar process

5. Posterior talofibular ligament

6. Posterior tibiofibular ligament

7. Transverse tibiofibular ligament

8. Tip of the medial malleolus/medial malleolus

9. Posteromedial gutter

10. Posteromedial talus/tibia

11. Posterocentral talus/tibia

12. Posterolateral talus/tibia

13. Posterolateral gutter

14. Tip of lateral malleolus

Additional (when indicated):

Posterior tibial tendon

Flexor digitorum tendon

Peroneal tendons

From Van Dijk CN, Scholten PE, Krips R: Arthroscopy 16:871, 2000.

 

 

 

Anterior Ankle Examination

The anterior arthroscopic examination always is performed initially through the anteromedial portal and then through the anterolateral portal. The structures that can be visualized are the following (from medial to lateral): (1)The deep portion of the deltoid ligament as it arises from the tip of the medial malleolus and its fibers run vertically down to the medial trochlear surface of the talus. This is an area where ossicles may be hidden, and it should be evaluated carefully for pathology. (2) Also noted is the articular surface of the tip of the medial malleolus as it corresponds and articulates with the medial talar dome and the posterior recess and posterior ligaments. The medial gutter includes the area from the deltoid ligament to below the medial dome of the talus. Areas of articular damage here should be carefully noted. The tibia articulates with the medial dome of the talus. This is the medial corner of the ankle. In this region, the anterior articular margin of the tibia deviates from its more horizontal configuration centrally and laterally to a more convex configuration in the coronal plane. At this medial articular notch, the arthroscope may be maneuvered most easily into the central and posterior aspects of the joint without damaging the articular surfaces.

The distal portion of the tibial lip directs slightly anteriorly in the sagittal plane. This portion of the tibia articulates within a depression in the talar surface and is called the sagittal groove. This groove lies between the medial and lateral shoulders of the talus and projects from anterior to posterior. At the area between the anterior tibial lip and the capsule is a periosteum-covered subchondral bone, the synovial recess. This extends from medial all the way to the lateral portion of the ankle. This is where tibial osteophytes develop and synovium and capsule become adherent at the margins of the osteophyte. More laterally, the trifurcation includes the distal lateral tibial plafond, the lateral dome, and the fibula and is bounded by the anterior inferior tibiofibular ligament superiorly. This relation is important in the ankle, because this is often the site of soft-tissue pathology. The syndesmotic or anterior inferior tibiofibular ligament runs at approximately a 45-degree angle from the lateral portion of the distal tibia to the fibula, just below the level of the lateral talus. The anterolateral talar dome also is the site of osteochondral lesions of the talus, and access into ankle joint usually is easy in this region. The lateral gutter is the space between the medial border of the fibular articulation and the lateral border of the talar articulation. It extends from below the anterior inferior tibiofibular ligament to the anterior talofibular ligament. This often is the site of chondromalacia and ossicles at the tip of the fibula within the ligament substance. The anterior talofibular ligament lies intracapsular and runs from the tip of the fibula to the inferior lateral portion of the talus. It can be easily reached for a shrinkage procedure in case of laxity in patients with chronic anterolateral ankle instability. The anterior gutter represents the capsular reflection anteriorly of the ankle as it inserts along the talar neck. There is a normal bare area proximal to the capsular insertion, similar to the area on the central portion of the distal tibia. A synovial recess also can be found at the anterior inferior aspect of the talar dome. In this area, anterior talar osteophytes may articulate or butt against osteophytes of the anterior tibial lip.[10]

Posterior Ankle Examination

Using a posterolateral and posteromedial portal with the patient in the prone position, one first approaches the fatty tissue overlying the joint capsule ( Fig. 16-10 ). This tissue can partially be removed. At the level of the ankle joint, the posterior tibiofibular ligaments and the posterior talofibular ligament can be recognized. After removal of the very thin joint capsule of the subtalar joint, the posterior compartment of the subtalar joint can be visualized. The posterior talar process can be freed of scar tissue and the FHL tendon identified. The FHL tendon is an important landmark to prevent damage to the more medially located neurovascular bundle. When manual distraction is applied to the os calcis, the posterior compartment of the ankle joint opens up and can be visualized. The arthroscope and instruments can be introduced into the posterior ankle compartment. Procedures such as a synovectomy and/or capsulectomy of both ankle and subtalar joint can be performed. On the medial side, the tip of the medial malleolus, as well as the deep portion of the deltoid ligament, can be visualized. Opening the joint capsule from inside out at the level of the medial malleolus permits the tendon sheath of the posterior tibial tendon to be opened and the arthroscope to be introduced into the tendon sheath. The posterior tibial tendon can be inspected. The talar dome and nearly the entire surface of the complete tibial plafond can be inspected, as well. An osteochondral defect or subchondral cystic lesion can be identified, debrided, and drilled. The posterior syndesmotic ligaments are inspected and, if hypertrophic, partially resected. The intrinsic syndesmotic area and the posterior talofibular ligament can be inspected (Figs. 16-11 and 16-12 [0110] [0120]). Removal of a symptomatic os trigonum or a nonunion of fracture of the posterior talar process involves partial detachment of the posterior talofibular ligament and release of the flexor retinaculum, both of which attach to the posterior talar prominence. Release of the FHL tendon involves detachment of the flexor retinaculum from the posterior talar process ( Fig. 16-13 ). Adhesions surrounding the flexor tendon can be removed. On the lateral side, the peroneal tendons can be inspected. A tight and thickened crural fascia can hinder the free movement of instruments; it can be helpful to enlarge the defect in the fascia by means of a punch or shaver.

 
 

Figure 16-10  Right ankle. Using a posterolateral and posteromedial portal with the patient in the prone position, one first approaches the fatty tissue overlying the joint capsule. This tissue can be partially removed.

 

 

 
 

Figure 16-11  Left ankle. Removal of a symptomatic os trigonum (OT) or a nonunion of fracture of the posterior talar process involves partial detachment of the posterior talofibular ligament and release of the flexor retinaculum, both of which attach to the posterior talar prominence.

 

 

 
 

Figure 16-12  Left ankle. Removal of a symptomatic os trigonum (OT) involves partial detachment of the posterior talofibular ligament (PTFL) and release of the flexor retinaculum, both of which attach to the posterior talar prominence (see also Fig. 16-13 ).

 

 

 
 

Figure 16-13  Left ankle. Release of the flexor hallucis longus retinaculum from the posterior talar process to remove a symptomatic os trigonum (OT) (see also Figs. 16-11 and 16-12 [0110] [0120]).

 

 

 

Specific indications

Anterior Ankle Impingement

Anterior ankle impingement syndrome is a clinical diagnosis characterized by anterior ankle pain with recognizable pain and a (slightly) limited dorsiflexion. [0100] [0160] Clinically, the patient complains of anterior joint pain made worse after activity such as walking up stairs or hills. Squatting or running is especially bothersome. Tenderness with recognition is localized over the anterior aspect of the ankle joint. Forced ankle dorsiflexion sometimes can provoke the complaints, but in most patients this test is negative. Plain radiographs may demonstrate anterior osteophytes. Additional oblique views (AMI views) can be helpful to demonstrate anteromedially located osteophytes ( Fig. 16-14, A and B ). [0160] [0170] In case of anterior ankle pain with negative x-ray findings, the most likely cause of the complaints is an anterior soft-tissue impediment.[18] Congenital plicae within the ankle, posttraumatic scar tissue, adhesions, or ganglions all may act as a local soft-tissue impediment with local swelling and recognizable pain on palpation.

 

 

Figure 16-14  (A) Plain lateral radiographs do not always demonstrate anterior located osteophytes, especially when they are located anteromedially. (B) Additional oblique views (AMI) in the same patient as in A now demonstrate anteromedially located osteophytes.

 

 

Scoring systems for anterior impingement use the location (tibia or talus) and size of osteophytes as prognostic factors for postoperative success. Scranton et al.[19] compared open resection with arthroscopic resection of painful anterior impingement spurs. They categorized ankle spurs from grades 1 through 4 according to the size of spurs and degree of involvement of the ankle, and demonstrated that the treatment and recovery correlated with the grade. Grades 1, 2, and 3 spurs could be resected arthroscopically or by arthrotomy. Grade 4 spurs initially were not thought to be appropriate for arthroscopic resection. However, as experience has increased, grade 4 spurs also can be resected arthroscopically. The reproducibility of this classification system may be doubtful because the correlation was assessed with outcomes at short-term follow-up (10 weeks postoperatively). It has been determined that the degree of osteoarthritic changes influences the outcome of treatment. Osteophytes without joint space narrowing are not a manifestation of osteoarthrosis; subsequently a “normal” joint remains after removal of these spurs. A classification for anterior ankle impingement based on the degree of degeneration was developed ( Table 16-3 ).[10]


Table 16-3   -- Classification System for Degenerative Changes of the Ankle

Grade

X-ray finding

1

Normal joint or subchondral sclerosis

2

Osteophytes without joint space narrowing

3

Joint space narrowing with or without osteophytes

4

(Sub) total disappearance or deformation of the joint space

From Van Dijk CN, Tol JL, Verheyen CCPM: Am J Sports Med 25:737, 1997.

 

 

 

The results at long-term follow-up show that the use of this osteoarthritic classification is more discriminating than the impingement classification of Scranton and McDermott as a predicting value for the outcome of arthroscopic surgery for anterior ankle impingement. [0100] [0190]

Soft-tissue pathology accounts for about 30% to 50% of lesions seen in the ankle joint.[18] The lesions usually involve the synovium, but the capsule or ligamentous tissues also may be affected. Soft-tissue impingement often is the primary cause of chronic ankle pain, usually after an ankle sprain. This can occur along the syndesmosis, the anterior gutter, or the syndesmotic interval between the tibia and fibula; underneath the ankle; or posteriorly in the syndesmosis and posterior gutter.[20]

Impingement of soft tissue often occurs in conjunction with bony impingement. Osteophytes can impinge into the capsule and synovium, resulting in an inflammatory reaction. The pain in a patient with bony impingement is most likely caused by this soft-tissue impingement and not by the bony impediments itself.[10]

In normal anatomy, the lower surface of the anterior tibia and the anterior part of the medial malleolus are covered with cartilage. The anterior joint capsule attaches onto the tibia above this cartilage rim, approximately 5mm above the joint line.[21] It is this nonweight-bearing anterior cartilage rim that undergoes the osteophytic transformation ( Fig. 16-15 ). Damage to this anterior cartilage rim is known to occur in the majority of inversion traumas. Depending on the degree of damage, a repair reaction with cartilage proliferation, scar tissue formation, and calcification follows. Additional damage by recurrent instability or forced ankle movement will further this process. Recurrent direct (micro) trauma to this anteriorly located cartilage rim could be another important factor.[21] Except for a thin subcutaneous layer, parts of the involved anterior cartilage rim (especially the anteromedial and anterolateral segments) are covered only by skin. Osteophytes are seen most commonly with a beak-like prominence of bone at the anterior lip of the tibia, usually associated with a corresponding area over the anterior neck of the talus. The talar abnormality may be a defect or an opposing osteophyte (“kissing lesion”).

 
 

Figure 16-15  Histologic sample of anterior joint capsule covering the anterior rim of the distal tibia and talus at the level of the ankle joint. In normal anatomy, the lower surface of the anterior tibia and the anterior part of the medial malleolus are covered with cartilage. The anterior joint capsule attaches onto the tibia above this cartilage rim, approximately 5mm above the joint line.[21] It is this nonweight-bearing anterior cartilage rim that undergoes the osteophytic transformation.

 

 

A common location for a soft-tissue impingement is the anterolateral gutter.22 Several studies report on patients with persistent pain and swelling over the anterolateral aspect of the ankle after an inversion sprain. Arthrotomy of these ankles reveals hyalinized connective tissue extending into the joint from the anterior inferior portion of the talofibular ligament. This tissue is called a “meniscoid” lesion by some authors.[23]

Patients generally have a synovitis surrounding the anterior inferior tibiofibular ligament, both in front and behind, as well as synovitis of the anterior talofibular ligament. In addition, a small ossicle or loose body may be hidden in the soft tissues at the tip of the fibula. Rarely, an adhesive thick scar band, previously described as a meniscoid lesion, is present, extending from the anterolateral aspect of the distal tibia to the lateral gutter. After surgical reconstruction of the lateral ankle ligaments, soft-tissue impingement may be present between the reconstructed ligaments and the talus.

In case of anterior and anteromedial located osteophytes, an additional soft-tissue impediment usually is present. During dorsiflexion, hypertrophic synovial tissue impinges between the osteophytes. Tol et al. [0210] [0240] concluded that the cause of pain is not the osteophyte itself but a soft-tissue impingement that occurs between the osteophytes. It can be hypothesized that removal of the soft-tissue impediment without removal of spurs would be sufficient. The presence of talar and tibial osteophytes, however, reduces the anterior joint space. After an arthroscopic intervention, a hematoma will be formed postoperatively that subsequently will develop into scar tissue. The scar tissue that fills the defect will act instantly as a new anterior soft-tissue impediment. It therefore is important to remove the osteophytes to enhance more anterior and anteromedial space and diminish the chance for a recurrence of symptoms. [0160] [0210] [0240]

Visualization of the anterior ankle joint can be improved by bringing the ankle into a forced dorsiflexion position because in this position the anterior working area opens up. Distraction makes the anterior capsule more tense over the osteophyte, and its use therefore is not recommended.[10] It is important to identify the anterior and superior borders of the osteophyte, and this often requires careful elevation or peeling of soft tissues from the confines of the osteophyte.

Surgical Technique

The patient is placed in a supine position with slight elevation of the ipsilateral buttock. The heel of the affected ankle rests on the very end of the operating table, thus making it possible for the surgeon to fully dorsiflex the ankle joint by leaning against the sole of the patient's foot ( Fig. 16-16 ). After making an anteromedial skin incision, the surgeon bluntly divides the subcutaneous layer with a hemostat. A 4-mm, 30-degree arthroscope routinely is used. The anterolateral portal is made under arthroscopic control. Additional portals just anterior to the tip of the lateral or medial malleolus are used only when indicated. Osteophytes are removed by a 4-mm chisel and burr. These spurs can be identified easily when the ankle is in a fully dorsiflexed position to prevent the anterior joint capsule from covering the osteophytes. Another advantage of the forced dorsiflexion position is the fact that the talus is concealed in the joint, thereby protecting the weight-bearing cartilage of the talus from potential iatrogenic damage. The contour of the anterior tibia is first identified by shaving away the tissue just superior to the osteophyte. An overcorrection of the medial malleolus generally is pursued by shaving some of it away after resection of the osteophyte.

 
 

Figure 16-16  The heel of the affected ankle rests on the end of the operating table, thus making it possible for the surgeon to dorsiflex the ankle joint fully by leaning against the sole of the patient's foot.

 

 

Rehabilitation

Postoperative rehabilitation consists of a compressive bandage and partial weight bearing for 3 to 5 days. The patient is instructed to actively dorsiflex his or her ankle and foot on awakening and to continue this exercise a few times every hour for the first 2 to 3 days after surgery.

Synovitis

Synovitis can be a noninflammatory, inflammatory, or septic process of the synovium, which is most characterized by joint swelling and tenderness. Synovitis can be caused by trauma or previous surgery. A generalized or localized synovitis can occur, most often with fibrous bands and adhesions. Synovitis accounts for approximately 30% of pathology seen in the ankle joint.[15]

Patients usually have complaints of aching, swelling, tenderness, and other signs of joint inflammation. A history of trauma or injury is more likely to cause a nonspecific type of synovitis, either localized or generalized; however, trauma also can trigger an underlying specific pathologic process. Radiographs often are negative. The clinical manifestation of soft-tissue lesions can be divided into the following:

  

1   

Impingement, lesions with local pain and swelling.

  

2   

Diffuse pain, swelling, calor, restriction of range of ankle motion in all directions.

  

3   

Deep ankle pain without recognizable pain on palpation, no local swelling, and only minor restriction of range of motion.

  

4   

Absence of symptoms.

Synovitis of the ankle may be a difficult diagnostic problem. Even after careful history, physical examination, and diagnostic testing, the diagnosis may not be readily apparent.

During arthroscopy, localized or generalized inflammation of the synovia can be present. It may contain hemosiderin or fibrin debris. Scarring, fibrosis, and adhesions often are seen in relation to the synovitis.

In 1997, Cheng and Ferkel[25] proposed the following classification system for synovial disorders:

  

   

Congenital: plicae or congenital bands within the ankle; plicae, or shelves, have been demonstrated in the knee but are difficult to find in the ankle. Congenital bands are seen as an incidental finding when examining the ankle for other types of pathology

  

   

Traumatic: sprains, fractures, and previous surgery

  

   

Rheumatic: rheumatoid arthritis, pigmented villonodular synovitis, crystal synovitis, hemophilia, and synovial chondromatosis

  

   

Infectious: bacterial and fungal

  

   

Degenerative: primary and secondary

  

   

Neuropathic: Charcot joint

  

   

Miscellaneous: ganglions, arthrofibrosis

Osteochondral Defects

An important cause of residual pain after an ankle sprain is an osteochondral lesion of the talus. It is defined as the separation of a fragment of articular cartilage, with or without subchondral bone. The incidence of an osteochondral lesion after an ankle sprain probably is underestimated because these lesions often remain undetected. The incidence has been reported to be as high as 6.5% after ankle sprains. Osteochondral defects of the talus most often occur in young adults, with a nearly equal distribution between the sexes. In the acute situation, symptoms depend on the amount of damage to the periarticular tissues and the involvement of afferent pain fibers in the subchondral bone. Usually the lesion is located in the anterolateral or posteromedial aspect of the talar dome. Histologically the medial and lateral lesions are identical, but morphologically they differ. The lateral lesions are shallow and more wafer shaped, indicating a shear mechanism of injury. In contrast, medial lesions generally are deep, cup shaped, and located posteriorly, indicating a mechanism of torsional impact. From an etiologic point of view, trauma is the most common cause of osteochondral lesions of the talus, but idiopathic osteonecrosis often may be the underlying pathologic process. In the literature the latter has been associated with alcohol abuse, use of steroids, endocrine disorders, and some hereditary conditions. Although initial symptoms may be absent, in chronic cases most patients present with intermittent pain located deep in the ankle joint that increases on weight bearing. On physical examination, signs often are lacking. A discrete limitation of range of motion with some synovitis may be present. Local tenderness on palpation with recognition is absent in most cases. Because there are no specific pathognomonic signs or symptoms, it is essential that the examining physician and radiologist be aware that an osteochondral lesion can be present. The frequent absence of radiographic changes on conventional radiographs has led to the use of more sensitive methods for detection. A heel-rise view can be helpful to detect an osteochondral lesion. A recent prospective study of Verhagen[26]demonstrated that with this additional view the chance of finding an osteochondral lesion of the talus with x-ray examination is doubled ( Fig. 16-17 ). CT scan and MRI can be helpful for the diagnosis and preoperative planning. In the prospective study of Verhagen, there was no statistically significant difference between the sensitivity and specificity of CT and MRI in detecting an osteochondral lesion of the talus.

 
 

Figure 16-17  A heel-rise view (left) demonstrates a posteromedially located osteochondral defect. Because of the relative posterior location of the defect, a plain anterior-posterior view (right) is not able to demonstrate this lesion.

 

 

Pritsch, Cheng, Ferkel, and Applegate developed an arthroscopic staging system that correlated well with the CT classification of Ferkel and Sgaglione (1994) [0290] [0280] [0290] and the MRI classification of Anderson et al. (1989). [0270] [0280] [0290] [0300] [0310] [0320] Recently, a new arthroscopic staging system was developed by Taranow et al.,[33] who classified cartilage as viable and intact (stage A) or breached and nonviable (stage B). The bone component was determined as follows: (1) stage 1 is a subchondral compression or bone bruise, (2) stage 2 lesions are subchondral cysts and are not seen acutely (these develop from stage 1 lesions), (3) stage 3 lesions are partially separated or detached fragments in situ, and (4) stage 4 represents displaced fragments. The condition of the cartilage and bone together determines the type of surgical treatment. Despite the existence of these classification systems, few authors base their decision for a specific treatment on these systems. A meta-analysis of Tol et al.[34]showed that the value of preoperative radiologic staging systems was of minor value in the preoperative planning because they hardly correlate with the perioperative findings. This demonstrates the shortcoming of preoperative radiologic staging systems as a guide for the treatment strategy. Perioperative staging of osteochondral defects therefore seems more appropriate. Eventually, the most rational way of preoperative assessment of osteochondral lesions is to determine whether they are symptomatic or asymptomatic.

Surgical Technique

From anterior to posterior the talar dome can be divided into four equal parts ( Fig. 16-18 ). When the osteochondral defect is located in one of the three “anterior” parts of the talar dome, it can be treated by a routine anterior ankle arthroscopy. When it is located in the most posterior quarter of the talar dome, the defect should be approached by a posterior ankle arthroscopy or by means of a medial malleolar osteotomy. The current treatment consists of removal of dead bone and overlying cartilage.[34] After debridement, the subchondral sclerotic zone is perforated with a burr or K-wire or by microfracturing. Preoperatively, it is desirable to decide whether to use mechanical distraction in combination with a 2.7-mm arthroscope or to use a standard 4-mm arthroscope and to treat the osteochondral defects in the anterior working area by forcing the ankle into full plantarflexion. The osteochondral defect in the posterior quarter of the talar dome is difficult to reach in the hyperplantarflexed position in patients having a diminished plantarflexion or in case of anterior osteophytes. [0330] [0350]

 
 

Figure 16-18  From anterior to posterior the talar dome can be divided into four equal parts. When an osteochondral defect is located in one of the three anterior parts it can be reached by a routine anterior ankle arthroscopy. Soft-tissue distraction might be necessary. When the lesion is located in the most posterior quarter, it can be reached only by posterior ankle arthroscopy.

 

 

Routinely the procedure is performed without distraction. The standard anteromedial and anterolateral approaches are created as described earlier. In an osteochondral defect located medially, the 4-mm arthroscope is moved over to the anterolateral portal and the instruments are introduced through the anteromedial portal. For an anterolateral defect, the arthroscope remains in the anteromedial portal and the instruments are introduced through the anterolateral portal. If osteophytes are present, they are removed first by chisel and/or burr. Synovitis located anterolaterally (in case of an anterolateral defect) or anteromedially (in case of an anteromedial defect) is removed by a 4.5- or 5.5-mm synovator. The extent of removal of osteophytes and synovitis is checked by bringing the ankle into plantarflexion. It now should be possible to palpate and visualize the osteochondral defects ( Fig. 16-19 ). If this is not the case, then a further synovectomy is performed in the dorsiflexed position. After sufficient synovectomy, it should be possible to identify the lesion in the forced plantarflexed position by palpating the cartilage with a probe. Not only can the lesion be palpated with a probe but it also should be possible to visualize at least the most anterior part of the lesion. It can be helpful to add soft-tissue distraction ( Fig. 16-20, A and B ).[24] If possible, a 3.5- or 4.5-mm synovator is now introduced into the defect. After the defect has been debrided by the synovator or curette, the arthroscope is moved over to the portal opposite the defect (the anteromedial portal in case of an anteromedial osteochondral defect) to check the completeness of the debridement. The scope then is brought back to the opposite portal and further debridement is performed. It is important to remove all dead bone and overlying, unsupported, unstable cartilage. Every step in the debridement procedure should be checked by regularly switching portals. A precise and complete debridement, with removal of all loose fragments, thus can be performed. Introduction of the instruments and the arthroscope is performed with the ankle in the fully dorsiflexed position, thus preventing iatrogenic cartilage damage. After full debridement, the sclerotic zone is performed by microfracturing technique, or multiple drill holes are made with a 2-mm burr or a 1.6-mm K-wire. A K-wire has the advantage of flexibility, whereas a 2-mm drill can break more easily if the position of the ankle is changed during drilling. When a 2-mm drill is used, a drill sleeve is necessary to protect the tissue.

 
 

Figure 16-19  An anterolateral located osteochondral defect of the talus. By bringing the ankle in full plantarflexion, the defect can be fully debrided. Completeness of the debridement can be checked by switching portals.

 

 

 

 

Figure 16-20  (A) A resterilizable soft-tissue distractor can be helpful to visualize lesions that are located more posteriorly in the ankle joint. (B) The amount of soft-tissue distraction can be adjusted by leaning more or less backward.

 

 

In posteriorly located lesions for which an anterior approach is chosen, a noninvasive traction device that allows the surgeon to change quickly from the fully dorsiflexed position (introduction of the instruments) to the distraction position offers obvious advantages. The distraction device consists of a belt around the waist of the surgeon that is connected to a noninvasive distraction loop placed around the ankle. The amount of distraction can be adjusted by leaning more or less backward (see Fig. 16-20, B ).

Loose Bodies and Ossicles

A loose body can be bony, chondral, or osteochondral. It arises from osteophytes or defects in the talus or tibia.

Ossicles, broken osteophytes, and chondral or osteochondral fragments arising from defects in the talus or tibia all can be considered loose bodies in the ankle joint. Sometimes, such a loose body is attached with scar tissue to the capsule or other structures, and then it is called a “corpus liberum pendulans.”[15] A small, loose body may cause catching symptoms along with pain, swelling, and limitation of motion. Symptoms of internal derangement may resolve if a small loose body becomes fixed to the synovial lining, ceasing to cause joint irritation. A loose body may grow by proliferation of chondroblasts/osteoblasts or may shrink because of the action of chondroblasts/osteoclasts.

The physical examination may not be very revealing, with vague areas of tenderness, possible limitation of motion, and catching. Rarely is a loose body palpable. As with all ankle problems, a careful physical examination must rule out extra-articular entities that can cause symptoms similar to intra-articular lesions. Peroneal subluxation, posterior tibial tendon attrition or rupture, tarsal tunnel syndrome, sinus tarsi syndrome, stress fracture, and tendinitis must be carefully excluded by both physical examination and ancillary studies. Plain radiographs usually reveal an osseous loose body, but chondral loose bodies are not visible on routine studies. A CT or MRI study is best suited to make the distinction between an intra-articular versus an extra-articular or intracapsular abnormality.

The arthroscopic approach to loose bodies is straightforward. Loose bodies localized to the anterior compartment, particularly in patients with ligamentous laxity, can be approached with a routine setup using anteromedial and anterolateral portals. However, the posterior joint also should be examined for the presence of loose bodies, which can hide in the posterior recess of the joint. [0130] [0350] A posterolateral portal can be made. Posteriorly located loose bodies can be removed best by means of a two-portal posterior approach.

Posterior Ankle Impingement

Posterior ankle syndrome is a pain syndrome. The patient experiences posterior ankle pain that is present mainly on forced plantarflexion. Posterior ankle impingement is caused by overuse or trauma.[13]Distinction between these two disorders seems important because posterior impingement through overuse has a better prognosis. A posterior ankle impingement syndrome is found mainly in ballet dancers and runners.

There are at least 10 specific causes for posterior ankle pain: os trigonum syndrome; posttraumatic calcifications, loose bodies, and bony avulsions; osteochondral defects; tendinitis of the FHL tendon; tendinitis of the posterior tibial tendon; tendinitis the peroneal tendons; tendinitis of the Achilles tendon; and ankle and subtalar arthrosis. [0130] [0350]

Os Trigonum Syndrome

The os trigonum is an inconsistently present accessory bone of the foot situated at the posterolateral aspect of the talus. It appears between the ages of 8 and 11 as a secondary center of ossification and usually fuses to the talus within 1 year after its appearance. When this ossification center remains separate from the talus it is referred to as the os trigonum. According to Sarrafian, the prevalence of this ossicle ranges from 1.7% to 7.7%.[36] When fusion does occur and there is a large, intact posterolateral process, it is referred to as a fused os trigonum. Since Rosenmuller first described the os trigonum in 1804, there has been controversy concerning its origin.[37] McDougall[38] believed it to be a secondary ossification center of the talus, whereas other authors state that it is a nonnunited fracture of the posterolateral talar process. The os trigonum usually remains asymptomatic, but an otherwise normal os trigonum can become symptomatic during or after strenuous physical activities or following an injury to the ankle. Sometimes an acute trauma in plantarflexion may result in contusion, compression, or fracture of the os trigonum or posterior process of the talus. These injuries may cause an overload posttraumatic syndrome of the os trigonum. In this condition, the os trigonum becomes painful but appears undisrupted on the lateral x-rays ( Fig. 16-21 ). On the other hand, chronic impingement of the posterior process of the talus against the tibia caused by chronic microtrauma or overuse by repeated hyperplantarflexion movements can lead to an inflammatory process of the os trigonum. It also can result in degenerative changes in the posterior capsule of the ankle joint, adjacent ligaments, tendon, and chondrosynovial surface.

 
 

Figure 16-21  Posttraumatic syndrome of the os trigonum of the right ankle. Plain lateral x-rays (left) reveal an undisrupted os trigonum. Additional posteromedial impingement views (PIM) with the foot in 25-degrees external rotation in the same patient show that the os trigonum is disrupted.

 

 

Clinically, the patient complains of pain during push-off while running. The pain often is absent during walking on level ground but appears on uneven terrain. Usually pain is complained of posterolaterally in the ankle joint but sometimes it may be located in the posteromedial region. Physical examination can reveal the presence of moderate swelling on only the medial or on both sides of the Achilles tendon, with tenderness on palpation.

A forced passive plantarflexion of ankle and foot will reproduce the recognizable symptoms. With this test the examiner performs repetitive, quick, passive forced plantarhyperflexion movements. The test can be repeated in slight exorotation or endorotation of the foot relative to the tibia. The investigator should apply this rotation movement on the point of maximal plantarflexion, thereby “grinding” the posterior talar process/os trigonum between the posterior tibial rim and calcaneus ( Fig. 16-22 ). A negative test rules out a posterior impingement syndrome. A positive test in combination with pain on posterolateral palpation can be followed by a diagnostic infiltration. The infiltration is performed from the posterolateral position between the prominent posterior talar process and the posterior edge of the tibia. If the pain disappears on forced plantarflexion, the diagnosis is confirmed. After clinical examination, a routine lateral radiograph of the ankle should reveal an os trigonum. Bone scanning can effectively localize osseous injuries in and around the talus by demonstrating increased uptake in the posterior talar region but is not very specific. A CT scan enables the surgeon to determine the exact location, size, and shape of the ossicle and therefore is valuable for preoperative planning ( Fig. 16-23, A and B ).

 
 

Figure 16-22  Forced passive plantarflexion test. This test will reproduce the recognizable symptoms. The examiner performs repetitive, quick, forced passive plantarhyperflexion movements. The investigator should apply rotational movements on the point of maximal plantarflexion, thereby “grinding” the posterior talar process/os trigonum between the posterior tibial rim and calcaneus.

 

 

 

 

Figure 16-23  (A and B) A computed tomography scan enables the surgeon to determine the exact location, size, and shape of loose ossicles and is therefore valuable for preoperative planning. (A) A loose fragment posterolateral in the ankle joint on a sagittal reconstruction.(B) Loose fragments between the distal fibula and talus of the left ankle.

 

 

FHL tendinitis often is present in patients with a symptomatic os trigonum with pain located posteromedially. The FHL tendon can be palpated behind the medial malleolus. By asking the patient to flex the toes repetitively with the ankle in 10- to 20-degrees plantarflexion, the FHL tendon can be palpated in its gliding channel behind the medial malleolus. During palpation there may be crepitus and recognizable pain.

A two-portal (posterolateral and posteromedial) approach with the patient in the prone position gives excellent access to the posterior ankle compartment of the ankle joint. The posterior compartment of the ankle joint thus can be visualized, and the subtalar joint, os trigonum, and FHL can be inspected. After inspection, the posterior talofibular ligament must be detached from the posterior talar process. The superior border of the posterior talar process is cleaned with the shaver, after which the FHL tendon can be inspected ( Fig. 16-24 ). The flexor retinaculum can be cut. After this has been performed, the posterior talocalcaneal ligament must be cut. Finally, the os trigonum can be detached with a chisel or small osteotome and subsequently removed ( Fig. 16-25 ).

 
 

Figure 16-24  Right ankle. Inspection of the flexor hallucis longus tendon in its channel. The view is from proximal to distal. See also Figs. 16-6 and 16-13 [0060] [0130].

 

 

 
 

Figure 16-25  Removal of an os trigonum with a chisel. On the left the flexor hallucis longus tendon is located.

 

 

Posttraumatic Calcifications, Loose Bodies, and Bony Avulsions

Calcifications, loose chondral or osteochondral fragments, and bony avulsions may result from major trauma to the ankle joint.[15] When the fragments are located in the posterior compartment of the ankle, they are most likely the result of a hyperplantarflexion trauma or a combination of strong inversion, plantarflexion, and external rotation of the tibia. In either case, an unsuspected chondral or osteochondral lesion may occur and result in a loose body floating in the posterior compartment of the ankle or subtalar joint.

Osteophytes of the posterior tibial rim, an os trigonum, and even part of the posterior talar process may break off during a hyperplantarflexion trauma and act as a loose body. After a severe inversion trauma, the posterior talofibular ligament may avulse a bony fragment from posterior talar process and may cause posterior ankle impingement.

Multiple loose cartilaginous or osteocartilaginous bodies also may form in synovial chondromatosis.

A small, loose body may cause catching symptoms with joint motion along with pain. Plantarflexion may be limited and painful during the hyperplantarflexion test. Plain lateral radiographs usually reveal an osseous loose body, but when located posteromedially it may overproject. An additional posteromedial impingement view (PIM) with the foot in 25-degree external rotation relative to the tibia is helpful when there is suspicion for bony pathology in posteromedial compartment of the ankle joint ( see Fig. 16-21 ). Lesions that appear on routine radiographs to be loose bodies may actually be intra-articular, intracapsular, or extra-articular in location, particularly in the posterior ankle joint compartment. The location of the lesions should be determined preoperatively to avoid embarrassment of performing an arthroscopic examination for loose body removal only to find the joint free of any abnormality. A CT scan is best suited to make the distinction between an intra-articular abnormality versus an extra-articular or intracapsular abnormality and to determine the exact location in the posterior ankle joint compartment.

Osteochondral Defects

In sagittal plane the talar dome can be divided into four equal quarters. When an osteochondral lesion is located in one of the anterior three quarters of the talar dome, it can be approached and treated by routine anterior ankle arthroscopy. The majority of the lesions can be treated in this manner. However, when the lesion is located in the most posterior quarter, the lesion can be treated by posterior ankle arthroscopy. A preoperative CT scan with sagittal image reconstructions is important to determine the exact location of the lesion ( Fig. 16-26 ). In case of a posteromedially located osteochondral defect, the FHL tendon should be inspected routinely. The tendon can be affected because of shredding of the tendon against the defect during flexion of the great toe while walking. When the tendon is affected, the flexor retinaculum should be cut and thus the tendon released and debrided.

 
 

Figure 16-26  A preoperative computed tomography (CT) scan with sagittal image reconstructions is important to determine the size and location of posterior located osteochondral defects. A sagittal CT reconstruction of a left ankle with an osteochondral defect that is located at the posterior end of the talar dome.

 

 

Tendinitis of the FHL Tendon

Tendinitis of the FHL tendon is caused most often by posterior overuse and posttraumatic injuries in ballet dancers and soccer players.[39] In the majority of cases it is a concomitant finding with other pathology, such as an os trigonum, loose bodies, bony avulsions, ankle and subtalar arthrosis, and their combinations. An unexpected but consequent finding that may cause FHL tendinitis is a posteriorly located osteochondral defect. The defect is located in the posterior quarter of the talar dome on the medial side. The tendinitis is maintained during the stance phase when walking. During this phase the ankle joint is in dorsiflexion. In this position the posterior talar dome is in closest contact with the tendon. The tendon, meanwhile, is moving in the opposite direction because the toes are actively flexed to start with the push-off phase. The tendon shreds against the osteochondral defects and becomes irritated and inflamed ( Fig. 16-27 ). In this way a posteriorly located osteochondral defect can cause an FHL tendinitis. In a consecutive series of patients with FHL tendinitis, the tendinitis was accompanied by os trigonum syndrome, bony avulsions, calcifications, and localized synovitis in 40 of 50 patients. In 7 patients the FHL tendinitis was combined with a posteromedial osteochondral defect, all located in the posterior quarter of the talar dome. Thus in only 3 patients did we find an isolated FHL tendinitis to be present.

 
 

Figure 16-27  In a cadaver specimen it is shown that the flexor hallucis longus tendon shreds against the posterior part of the talus (often the place where osteochondral defects are located) during dorsiflexion (see text).

 

 

The pain of an FHL tendinitis is located posteromedially. The tendon can be palpated behind the medial malleolus. By asking the patient to flex the toes repetitively with the ankle in 10- to 20-degrees plantarflexion, the FHL tendon can be palpated in its gliding channel behind the medial malleolus. The tendon glides up and down under the palpating finger of the examiner. In case of stenosing tendinitis or chronic inflammation, there may be crepitus and recognizable pain. Sometimes a nodule in the tendon can be felt to move up and down under the palpating finger.[40]

During posterior ankle arthroscopy, the FHL tendon is an important landmark to prevent damage to the more medially located neurovascular bundle. [0130] [0350] When a tendinitis is present, it is treated by performing a release of the flexor retinaculum ( Fig. 16-28 ). Adhesions surrounding the FHL tendon can be removed.

 
 

Figure 16-28  Release of the flexor retinaculum in a left ankle. Adhesions surrounding the flexor hallucis longus tendon are removed.

 

 

Tendinitis of the Posterior Tibial Tendon

The posterior tibial tendon plays an important role in normal hindfoot function. It plantarflexes and supinates the foot and thus prevents valgus deformity. Several authors have described a series of stages of posterior tibial tendon dysfunction as the disease progresses from peritendinitis to elongation and degeneration of the tibialis posterior tendon with fixed valgus deformation of the foot.[39] Tenosynovitis is often seen in association with flatfoot deformity or a prominent navicular tubercle and, to a lesser extent, in association with psoriatic and rheumatoid arthritis. In the early stage of posterior tibial tendinitis, tenosynovectomy can be performed if conservative treatment fails. Postsurgery and postfracture adhesions and irregularity in the contour of the posterior aspect of the tibia/medial malleolus can account for a symptomatic posterior tibial tendon. Posttraumatic calcification in the posteromedial joint capsule can produce symptoms of posterior tibial tendinitis because of the close connection of joint capsule and posterior tibial tendon sheath in this region. In a cadaveric study, we found a consistent membranous mesotendineal structure between tendon and tendon sheath.[39] This thin, vincula-like structure runs between the posterior tibial tendon and tendon sheath and attaches to the tendon sheath of the flexor digitorum tendon. It runs from the proximal end all the way with a free edge approximately 4 to 5cm above the level of the posteromedial tip of the malleolus. After traumatic injury to the ankle, these mesotendineal structures may have clinical implications.

The main portal for posterior tibial tendoscopy is located directly over the tendon, 2cm distal to the posterior edge of the medial malleolus. The distal portal is made first, with an incision through the skin. The tendon sheath is penetrated by the arthroscope shaft with a blunt trocar. A 2.7-mm arthroscope with an inclination angle of 30 degrees is introduced ( Fig. 16-29 ). After a spinal needle is introduced under direct vision, an incision is made through the skin into the tendon sheath to create a proximal portal. Instruments such as shaver system can be introduced. Through the distal portal a complete overview can be obtained of the posterior tibial tendon, from its insertion (navicular bone) to approximately 6cm above the level of the tip of the medial malleolus.

 
 

Figure 16-29  Right ankle. The distal portal for posterior tibial tendoscopy is located directly over the tendon 2cm distal to the posterior edge of the medial malleolus. A 2.7-mm arthroscope is introduced.

 

 

The complete tendon sheath can be inspected by rotating the scope over the tendon. Special attention should be given to inspect the tendon sheath covering the deltoid ligament, the posterior medial malleolus surface, and the posterior joint capsule. More proximal, the free edge of the vincula is inspected. The posterior joint capsule can be palpated and removed with a shaver system. The arthroscope is placed from the distal portal between tendon and medial malleolus. The shaver comes down from the proximal portal. Once the arthrotomy is made, the arthroscope and instruments can be manipulated into the posteromedial compartment of the ankle joint. Synovectomy or loose body removal thus can be performed.

Tendinitis of the Peroneal Tendons

Tenosynovitis of the peroneal tendons, (recurrent) dislocation, rupture, and snapping of one of the peroneal tendons account for most of the symptoms at the posterolateral side of the ankle joint. [0390] [0410]This disorder must be differentiated from fatigue fractures of the fibula, lesions of the lateral ligament complex, and posterolateral impingement (os trigonum syndrome). Peroneal tendon disorders often are associated and secondary to chronic lateral ankle instability.[41] Because the peroneal muscles act as lateral ankle stabilizers, more strain is placed on their tendons in the presence of chronic lateral instability, resulting in hypertrophic tendinopathy, tenosynovitis, and ultimately in (partial) tendon tears. The diagnosis may be difficult in patients with lateral ankle pain. Recurrent peroneal tendon dislocation and tenosynovitis can be established by clinical examination. In the case of subtotal tears of the peroneus brevis or longus tendon, supplemental investigations such as MRI or ultrasonography can be helpful for establishing the diagnosis. Postsurgery and postfracture adhesions and irregularities in the posterior aspect of the fibula where the gliding channel of the tendon is located can be responsible for symptoms in this region.

The main portal for peroneal tendoscopy is located directly over the tendons, 2cm distal to the posterior edge of the lateral malleolus. The distal portal is made first, with an incision through the skin. The tendon sheath is penetrated by the arthroscope shaft with a blunt trocar. A 2.7-mm arthroscope with an inclination angle of 30 degrees is introduced ( Fig. 16-30 ). After a spinal needle is introduced under direct vision, an incision is made through the skin into the tendon sheath to create a proximal portal. Instruments such as shaver system can be introduced. Through the distal portal on the lateral side, a complete overview can be obtained of both peroneal tendons. The inspection starts approximately 6cm proximal from the posterior tip of the lateral malleolus, where a thin membrane splits the tendon compartment into two chambers ( Fig. 16-31 ). More distally, both tendons lie in one compartment. The complete compartment can be inspected by rotating the endoscope over and between the two tendons. The vincula-like membrane by which both tendons are attached to the tendon sheath allows the arthroscope to rotate freely all around each tendon. The muscle fibers of the peroneus brevis can be recognized in the thin membrane up to the tip of the fibula. At this location both tendons cross the calcaneofibular ligament, which usually gives some fibers to the anterior talofibular ligament. Approximately 3 to 5cm distal from the fibula the tendons cross each other and again get divided by a membrane and a bony prominence. With the tendoscopy a pathologic thickened vincula or tendon sheath can be released, adhesions can be removed, and a symptomatic prominent tubercle can be removed. A rupture of the peroneal longus or brevis tendon can be sutured. When a total synovectomy of the tendon sheath is to be performed, it is advisable to create a third portal more distal or more proximal from the previously described portals. In case of treatment for recurrent peroneal tendon dislocation, it is possible to deepen the groove of the peroneal tendons with a burr.[42]

 
 

Figure 16-30  Left ankle. The main portal for peroneal tendoscopy is located directly over the tendons 2cm distal to the posterior edge of the lateral malleolus. The distal portal is made first. A 2.7-mm scope can be introduced. The proximal portal is created under direct vision.

 

 

 
 

Figure 16-31  Through the distal portal a complete overview can be obtained of both peroneal tendons. The inspection starts approximately 6cm proximal from the posterior tip of the lateral malleolus where a thin membrane splits the tendon compartment into two chambers(1). More distally (2, 3) both tendons lie in one compartment.

 

 

Tendinitis and Paratendinitis in the Achilles Tendon

Overuse injuries of the Achilles tendon can be divided into insertional and noninsertional tendinitis. Because there is no evidence of inflammation in patients with “tendinitis,” the term tendinosis has been proposed. [0390] [0430]

Noninsertional tendinitis can be divided into three subgroups: paratendinitis, paratendinitis + tendinosis, and tendinosis.

Paratendinitis is characterized by inflammation on only the lining of the tendon. With acute tendinitis there is diffuse swelling around the tendon. Most cases of isolated paratendinitis respond well to conservative treatment.

In patients with paratendinitis plus tendinosis there is localized swelling, most often 4 to 7cm above the insertion of the Achilles tendon ( Fig. 16-32 ). On examination there is pain, particularly when the tendon is squeezed. Most often the pain is localized predominantly on the medial side. MRI demonstrates marked thickening of the tendon.

 
 

Figure 16-32  Left ankle. In patients with paratendinitis and tendinosis there is localized swelling approximately 4 to 7cm above the insertion of the Achilles tendon.

 

 

In patients with Achilles tendinosis, fields of local degeneration in the tendon are present. With advanced tendinosis, the tendon elongates because of chronic degeneration and is no longer in functional continuity. There often is an increase in passive range of dorsiflexion.

Heavy-load eccentric calf-muscle training has been demonstrated to be effective treatment for chronic Achilles + paratendinitis. For operative treatment of paratendinitis, the diseased and thickened paratenon is excised. Operative treatment of chronic tendinosis consists of debridement of the paratenon and removal of degenerative necrotic tissue. The thickened degenerative portion of the tendon is excised, and the defect is closed primarily.

Revascularization is stimulated by making multiple longitudinal incisions into the tendon. Open surgery produces a guarded prognosis. In fact, Maffulli et al.[44] reported poor results in more than 60% of patients.

For peritendinitis of the Achilles tendon, the portals are created 2cm proximal and 2cm distal of the lesion ( Fig. 16-33 ). The distal portal is made first: an incision is made through to the skin only. The crural fascia is penetrated by the arthroscope shaft with a blunt trocar, and a 2.7-mm arthroscope with an inclination angle of 30 degrees is introduced. After a spinal needle is introduced under direct vision, an incision is made at the location of the proximal portal. An instrument such as a probe or a small shaver is introduced. The pathologic paratenon is removed by use of the shaver. The Achilles tendon can be inspected by rotation of the scope over the tendon. The plantaris tendon can be recognized and released, or resected when indicated.

 
 

Figure 16-33  For peritendinitis of the Achilles tendon, the portals are created 2cm distal and proximal of the lesion. After a spinal needle is introduced under direct vision, an incision is made at the location of the proximal portal.

 

 

Insertional Tendonitis and Retrocalcaneal Bursitis

Insertional tendonitis can be classified as retrocalcaneal bursitis, retrocalcaneal bursitis + insertional tendonitis, and insertional tendonitis.

Chronic retrocalcaneal bursitis is accompanied by deep pain and swelling of the posterior soft tissue just in front of the Achilles tendon ( Fig. 16-34 ). The prominent bursa can be palpated medially and laterally from the tendon at its insertion. The lateral radiograph demonstrates the characteristic prominent superior calcaneal deformity. Operative treatment involves removal of the bursa and resection of the lateral and medial posterosuperior aspect of the calcaneus. Retrocalcaneal bursitis often is accompanied by midportion insertional tendinosis. Often a partial rupture of the midportion of the tendon is present at its insertion. When operative treatment for retrocalcaneal bursitis is indicated, debridement of the midportion of the Achilles insertion should be considered in case of a partial rupture.[39]

 

 

Figure 16-34  (A) Achillotendoscopy: retrocalcaneal bursitis. (B) After removal of the bursa and inflamed soft tissue, the calcaneal prominence is removed with a full-radius resector and small acromionizer.

 

 

In case of insertional tendinosis, there is pain at the bone-tendon junction that worsens after exercise. The tenderness is specifically located directly posterior to the junction. Radiographic signs of ossification at the most distal extent of the insertion of the tendon (bone spur) are typical signs of insertional Achilles tendinosis. Most patients can be managed with nonoperative means, such as widening and deepening of the heel counter of the shoe. When operative treatment is indicated, the pathologic ossifications and spurs can best be approached by a central heel-splitting incision.

Open surgery for insertional tendinitis with removal of the chronically inflamed bursa and the posterosuperior prominence of the calcaneus can be associated with a poor outcome. Open surgical treatment requires plaster immobilization to prevent equines malformation and to stimulate wound healing. Angermann and Hovgaard[45] reported a cure rate of only 50% after open surgery for chronic retrocalcaneal bursitis. Endoscopic treatment offers the advantage of less morbidity, reduced postoperative pain, and outpatient treatment.

Achillotendoscopy for retrocalcaneal bursitis is performed with the patient in the prone position. Two portals are created, medial and lateral to the Achilles tendon, at the level of the superior border of the os calcis. A 4-mm arthroscope with an inclination angle of 30 degrees is introduced through the posterolateral portal. A probe and subsequently a 5-mm, full-radius resector are introduced through the posteromedial portal. After removing of the bursa and inflamed soft tissue, the surgeon uses a full-radius resector and small acromionizer to remove the calcaneal prominence.

Subtalar Joint Arthroscopy, Intraosseous Talar Cysts

Subtalar arthroscopy was first described in 1985.[46] The procedure may be applied as a diagnostic and therapeutic tool. As with any other joint, the subtalar joint should be compartmentalized and examined. Indications are the evaluation of subtalar instability, debridement of osteochondral lesions, and excision of avulsion fragments or loose bodies. The anterior subtalar joint consists of the anterior facet, middle facet, talonavicular joint, and spring ligament. The dividing axis through the subtalar joint consists of the sinus tarsi, tarsal canal, cervical ligament, talocalcaneal interosseous ligament, inferior extensor retinaculum, and fat pad. The posterior subtalar joint consists of the posterior facet that is 40 to 45 degrees lateral to the longitudinal axis of the foot, the capsule, the posterior recess, the lateral recess (thickened by the calcaneofibular ligament), and calcaneus. The patient may be positioned supine or laterally with a bolster under the foot at the edge of the table. A 1.9- to 2.7-mm arthroscope with 30-degree wide angle is used. Small joint shavers and burrs can be introduced. When needed, soft-tissue distraction can be performed. Four portals have been described.[46] The anterior lateral portal is made in the sinus tarsi 2cm anterior and 1cm inferior to the tip of the lateral malleolus. Caution should be taken not to injure the superficial peroneal nerve. The inframalleolar portal is made anterior to the calcaneofibular ligament. Caution should be taken not to injure the peroneal tendons. The posterior lateral portal is made 1cm posterior and 1cm proximal to the tip of the fibula ( Fig. 16-35 ). Caution should be taken not to injure the sural nerve, lesser saphenous vein, and peroneal tendons. The medial portal is made in the sinus tarsi approximately 2cm anterior to the tip of the lateral malleolus. A blunt trocar is introduced through the deep fascia and guided gently through the tarsal canal to the medial skin surface. The foot is placed in equinus to relax the neurovascular structures. An incision is made over the trocar. A blunt trocar is introduced from the medial portal. The joint is insufflated and the arthroscope is introduced to view the anterior lateral and posterior medial subtalar joint. Caution is taken to avoid the neurovascular structures, which are approximately 2.5cm distal to the tip of the medial malleolus. A systematic examination of the subtalar joint is performed by varying the portal placement of the scope. An arthroscope in the anterior lateral portal enables evaluation of the sinus tarsi, interosseous ligament, cervical ligament, and lateral and posterior gutters. An arthroscope in the posterior lateral portal enables evaluation of the lateral gutter and lateral compartment. An arthroscope in the medial portal enables evaluation of the anterior lateral and posterior medial compartments. The major complications specific to this procedure are sural nerve injury at the posterior lateral portal, superficial peroneal nerve injury at the anterior lateral portal, and peroneal tendon disruption at the inframalleolar portal. The arthroscope may be placed inadvertently in the ankle joint or may penetrate the capsule of the ankle and enter the lateral ankle gutter. For this reason, fluoroscopic confirmation of position can be useful.

 
 

Figure 16-35  Subtalar joint arthroscopy: the posterior lateral portal is made approximately 1cm posterior and 1cm proximal to the tip of the fibula.

 

 

Assessment of the posterior articulation of the subtalar joint can best be performed by means of a two-portal endoscopic approach of the hindfoot with the patient in the prone position.[13] The therapeutic indications include debridement of chondromalacia, excision of osteophytes, the removal of a loose body, lysis of adhesions with posttraumatic arthrofibrosis, and synovectomy. Intraosseous talar cysts can be approached through the subtalar joint.[47] Retrograde curettage of these lesions with destruction of the surrounding zone of sclerosis, along with bone grafting, is our treatment of choice. Lesions with a communication to the subtalar joint can be treated with the patient in the prone position (see Fig. 16-1 ). For proper preoperative planning, a CT scan is indispensable.

A shaver is introduced through the posteromedial portal. After identification of the FHL tendon, the posterior talar process is freed from its capsular attachments. The joint capsule of the subtalar joint is resected, and the opening of the cyst in the subtalar joint is identified by direct vision and palpation by means of a small probe ( Fig. 16-36, A and B ). With the endoscope in the posteromedial portal and the probe in place through the same posterolateral portal, the drill guide is introduced. The drill guide is parallel to the probe of which the curved tip is in place in the opening of the cyst in the subtalar joint. The drill guide is positioned onto the posterior talar process and a hole is drilled into the cystic lesion with a 4.5-mm drill (Figs. 16-37 and 16-38 [0370] [0380]). The lesion is curetted and debrided with a closed-cup curette. The opening of the cyst is enlarged to 6.5mm, and a 6.5-mm blunt trocar is introduced. Multiple drill holes are made through the cystic wall from inside the lesion with a K-wire ( Fig. 16-38 ). Cancellous bone obtained from the iliac crest is packed into the cystic lesion through the trocar ( Fig. 16-39 ). This two-portal endoscopic approach offers an excellent alternative to open techniques with obvious advantages. An arthrotomy or malleolar osteotomy is prevented. The articular origin of a cyst can be identified under direct arthroscopic vision. A second portal makes it possible to probe and subsequently treat the lesion by debridement, drilling, and transtrocar bone grafting. Excellent results at follow-up have been reported by using this technique. [0130] [0470]

 

 

Figure 16-36  (A and B) A computed tomography (CT) scan is indispensable for proper preoperative planning. This CT scan shows an intraosseous cyst of the right talus that has communication with the subtalar joint.

 

 

 
 

Figure 16-37  The opening of the cyst (see Fig. 16-36 , A and B and text) in the subtalar joint is identified by direct vision and palpation by means of a small probe.

 

 

 
 

Figure 16-38  The drill guide is positioned, parallel to the probe, onto the posterior talar process. With a 4.5-mm drill, a hole is drilled into the cystic lesion.

 

 

 
 

Figure 16-39  Cancellous bone obtained from the iliac crest is packed into the cystic lesion through a trocar.

 

 

Combined Anterior and Posterior Ankle Arthroscopy

In case of combined anterior and posterior ankle pathology, anterior arthroscopy can be combined with posterior arthroscopy of ankle in the same operative setting. Indications are rheumatoid arthritis, pigmented villonodular synovitis, chondromatosis, or ankylosis.

The patient first is placed in the prone position. A tourniquet is applied and a small support is placed under the lower leg. A two-portal endoscopic approach of the hindfoot is performed and the pathology treated. When the procedure has been finished and the portals closed and the wounded draped, a strap is placed around the foot, the knee is flexed approximately 90 degrees, and the strap is attached with a string to the ceiling of the operating room. The foot is now hanging upside down ( Fig. 16-40 ). Next, the portals for the anterior ankle arthroscopy are made and synovectomy or capsulectomy is performed in the anterior ankle compartment. We have successfully performed this combined procedure with various indications in seven patients.

 
 

Figure 16-40  Combined anterior and posterior ankle arthroscopy. Posterior ankle examination is carried out with the patient in the prone position. Anterior ankle examination is carried out with the foot hanging upside down.

 

 

 

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