DEFINITION

Because of their nature and deep location, posterior ankle problems pose a diagnostic and therapeutic challenge.

Arthroscopic evaluation of posterior ankle problems by means of routine ankle arthroscopy using an anteromedial, anterolateral, and posterolateral portal is difficult because of the shape of the ankle joint. In cases in which the ankle ligaments are lax, it is possible to visualize and treat the pathology of the ankle joint itself, but pericapsular or extracapsular posterior pathologic conditions are not accessible through conventional arthroscopic portals.

A two-portal posterior endoscopic approach with the patient in the prone position affords excellent access to the posterior ankle, the subtalar joint, and the pericapsular and extra-articular structures.22

 

 

ANATOMY

 

Posterior ankle arthroscopy and hindfoot endoscopy enable visualization and accessibility to the posterior half of the tibiotalar joint, the subtalar joint, and extra-articular structures such as the os trigonum, the flexor hallucis longus (FHL) tendon, and the posterior syndesmotic ligaments.

 

The posterior intermalleolar ligament, also called the tibial slip or marsupial meniscus, is a structure with consistent location but varying size and width. It is distinct from the posteroinferior tibiofibular ligament and

separated from it by a small gap filled with synovial tissue.2

 

The os trigonum is a secondary center of ossification of the talus. It is present in 1.7% to 7% of normal feet.4 When this ossification center remains separate from the posterolateral process of the talus (the trigonal process or the Stieda process), it is referred to as the os trigonum. The prevalence of unilateral and bilateral (ununited) os trigona

is 10% and 1.402%, respectively.4,17

 

The FHL tendon originates in the posterior leg then runs within a tendon sheath that begins 1 cm proximal to the subtalar joint and binds the tendon to the posterior talus and calcaneus, forming the fibro-osseous tunnel, which

may restrict FHL motion.6,10

 

The posteromedial neurovascular bundle (tibial nerve and posterior tibial artery) are consistently medial to the FHL tendon throughout its course. Instruments introduced from the posteromedial portal do not risk injuring the

neurovascular bundle provided they remain lateral to the FHL.7 Sitler et al15 dissected 13 cadavers and found that the tibial nerve was located posterior to the FHL tendon in two specimens.

 

A posteromedial portal located 1 cm proximal to the level of the tip of the lateral malleolus is on average 2.9 mm further removed from the medial neurovascular bundle than a portal placed 1 cm more proximally.7

PATHOGENESIS

 

Posterior ankle pain may be a result of the following:

 

 

Posterior ankle impingement or os trigonum syndrome

 

 

 

FHL, posterior tibial, or peroneal tendinopathy Posttraumatic calcifications or exostoses Bony avulsions

 

Tibiotalar or subtalar loose bodies

 

 

Tibiotalar or subtalar osteochondral lesions or arthrosis Any combination of these entities

 

Overuse injuries play an important role in the pathogenesis of posterior ankle pain.

 

Repetitive minor trauma in the ankle, as seen in athletes, can induce posterior ankle and/or hindfoot osteophyte formation.18

 

Typically, to produce symptoms, an os trigonum must be disturbed by some traumatic event, such as a supination or forced plantarflexion injuries, dancing on hard surfaces, or pushing beyond physiologic limits.18

 

The pain is thought to be a result of the following:

 

 

Symptomatic motion between the relatively unstable os trigonum and talus

 

 

 

Compression of thickened joint capsules (intermalleolar ligament)1 Impinging scar tissue between the os trigonum and tibia

 

Compression between os trigonum and calcaneus (referred to as dancer's heel)

 

 

Irritation of the FHL tendon that courses between the os trigonum and the medial tubercle of the talus6,18 FHL tendinopathy is usually attributable to stenosing tenosynovitis rather than tendinosis or rupture3; it has only

rarely been reported at sites other than the posteromedial ankle.3,10 However, immunohistochemical studies have suggested an avascular zone of the tendon in the segment of tendon that passes behind the talus.14

NATURAL HISTORY

 

Patients present with posterior ankle pain.

 

Posterior ankle impingement can be caused by overuse (chronic pain) or trauma (acute pain). It is important to differentiate between these two because posterior impingement from overuse has a better prognosis.18

 

Overuse injuries typically occur in ballet dancers, soccer players, and downhill runners.3,21

 

In chronic conditions, stenosing tenosynovitis of the FHL tendon may coexist with os trigonum syndrome; this leads to poorer outcome if surgical treatment is delayed.4

 

16

 

Nonsurgical treatment for os trigonum syndrome is successful in approximately 60% of patients.8

 

PATIENT HISTORY AND PHYSICAL FINDINGS

 

 

Patients experience deep pain in the posterior aspect of the ankle joint, mainly with forced plantarflexion. On examination, there is pain on palpation of the posterior aspect of the talus.

 

During the passive forced plantarflexion test, the investigator can apply a rotational movement on the point of maximal plantarflexion, thereby “grinding” the posterior talar process or os trigonum between the tibia and the calcaneus.

 

A positive test result, in combination with pain on posterolateral palpation, should be followed by a diagnostic infiltration of an anesthetic (with or without corticosteroid).

 

Posteromedial pain on palpation does not necessarily indicate impingement.18

 

Tenderness on palpation over the musculotendinous junction of the FHL is diagnostic for FHL tendinitis; pain can be elicited by forced simultaneous ankle and first metatarsophalangeal joint dorsiflexion.3,10

 

“Pseudo hallux rigidus” may coexist with posteromedial ankle pain. Hallux dorsiflexion may be limited with ankle dorsiflexion but restored with ankle plantarflexion. This examination finding/phenomenon has been reported to be secondary to nodular thickening of the proximal FHL that impinges within the fibro-osseous tunnel on the

posteromedial ankle.10

 

Palpation of posterior talar process is a sensitive test for posterior ankle impingement. A positive test should be followed by a hyperplantarflexion test.

 

The hyperplantarflexion test is positive when the patient experiences recognizable pain at the moment of impact. It is a highly sensitive test for posterior ankle impingement. A negative test rules out a posterior ankle impingement syndrome.

 

 

If the pain on forced plantarflexion disappears, the diagnosis is confirmed. Posteromedial ankle palpation is sensitive for FHL tendinitis.

IMAGING AND OTHER DIAGNOSTIC STUDIES

 

In patients with posterior ankle impingement, the anteroposterior (AP) ankle view typically fails to demonstrate abnormalities (FIG 1A).

 

 

On the lateral view, a prominent posterior talar process or os trigonum can sometimes be recognized.

 

 

 

 

FIG 1 • Imaging of posterior ankle impingement. A. AP ankle view showing no abnormalities. B. Standard lateral view. C. Lateral radiograph with the foot in 25 degrees of external rotation. D. Sagittal CT scan showing os trigonum.

 

 

As the posterolaterally located posterior talar process or os trigonum is often superimposed on the medial talar tubercle, detection of an os trigonum on a standard lateral view is often not possible (FIG 1B).

 

For the same reason, calcifications can sometimes not be detected by this standard lateral view.

 

We recommend lateral radiographs with the foot in 25 degrees of external rotation in relation to the standard lateral radiographs (FIG 1C).

 

 

Bone scintigraphy effectively localizes talar and peritalar injuries.5

 

Computed tomography defines the exact size and location of calcifications, bony fragments, osteochondral lesions, or intraosseous talar cysts (FIG 1D).

 

Magnetic resonance imaging (MRI) is useful for detection of bone contusions, edema, posterior capsular or ligament thickening,1 talar osteochondral lesions, and FHL tenosynovitis.

 

MRI has been reported to accurately identify FHL tendinitis in 82% of patients,10 represented by intermediate or low signal intensity on T2-weighted images.4

 

Fluid in the FHL tendon sheath is frequently seen in MRI without clinical signs of FHL tendinitis. Fluid in the tendon sheath of the FHL must be combined with changes in the tendon itself to be a sign of a tendinitis.

 

Bone edema in the os trigonum is an important diagnostic finding.

 

 

It is a sign of chronic compression of the os trigonum between distal tibia and calcaneus.

 

It can be a sign of degeneration of the cartilage of the undersurface of the os trigonum. In these cases, the bone edema is combined with bone edema of the calcaneus.

 

It can also be a sign of movement between the os trigonum and the talus. In these cases, there is bone edema in the posterior talus as well. These cases represent a pseudoarthrosis type of lesion.

 

DIFFERENTIAL DIAGNOSIS

 

 

 

Tarsal tunnel syndrome Plantar fasciitis Peroneal tenosynovitis

 

Posterior tibial tenosynovitis

 

 

Pseudo hallux rigidus (in FHL tenosynovitis) Bony avulsions

 

Ankle and subtalar arthrosis

 

 

17

 

 

Table 1 Indications for Posterior Ankle Arthroscopy and Hindfoot Endoscopy

 

Articular pathology

 

Posterior compartment ankle joint

 

Débridement and drilling of osteochondral defects

 

Removal of loose bodies, ossicles, calcifications, avulsion fragments Resection of posterior tibial rim osteophytes

Treatment of chondromatosis and chronic synovitis Posterior compartment subtalar joint

Removal of osteophytes and loose bodies

 

Subtalar arthrodesis

 

 

	Treatment of intraosseous talar ganglions by retrograde curetting and drilling Periarticular pathology Posterior ankle impingement   Deep portion of deltoid ligament: removal of posttraumatic calcifications or ossicles   Flexor hallucis longus stenosing tenosynovitis: débridement of flexor retinaculum, posterior talofibular ligament, prominent talar process, and opening the sheath of the tendon   Posterior syndesmotic ligaments: Hypertrophic ligaments can be excised.

 

 

 

 

NONOPERATIVE MANAGEMENT

 

Initial treatment of os trigonum syndrome consists of rest, ice, anti-inflammatory medication, avoidance of forced plantarflexion, and, occasionally, ankle immobilization for 4 to 6 weeks. If there is an established nonunion,

immobilization with casting is not recommended.8

 

 

Physical therapy, such as progressive resistive exercises and strengthening, may be helpful.8 Corticosteroid injection for os trigonum syndrome can effectively provide temporary pain relief.4,8

 

Nonsurgical treatment for FHL tenosynovitis includes rest, ice, anti-inflammatories, longitudinal arch supports,

standard physical therapy, and stretching exercises.8,10

 

SURGICAL MANAGEMENT

 

Indications for posterior ankle arthroscopy and hindfoot endoscopy are listed in Table 1.

 

 

The procedure is performed as outpatient surgery with the patient under general or epidural anesthesia.20

 

Preoperative Planning

 

All imaging studies are reviewed to address not only the individual pathology but also the associated bone, cartilage, or ligament injuries, as well as osteophytes, loose bodies, accessory muscles, and calcifications (FIG 2).

 

 

 

 

FIG 2 • Preoperative planning for débridement and drilling of a subtalar osteochondral cyst lesion in a right ankle. Coronal (A), sagittal (B), and axial (C) CT images showing the subtalar osteochondral defect and secondary cyst lesion.

 

 

 

FIG 3 • Positioning for hindfoot endoscopy. Small leg support (A),tourniquet (B), and leg holder (C).

 

 

Ankle and subtalar joint stability, stability of the peroneal tendons, and Achilles tendon tightness should be determined by examination under anesthesia.

 

 

Instability is a clinical diagnosis, and these patients are identified by their symptoms. They complain of recurrent giving-way. Laxity can be present without clinical symptoms of giving. If laxity is detected without clinical symptoms of giving-way, it is not an indication for lateral ligament reconstruction.

 

For irrigation, a single bag of normal saline with gravity flow can be used.

 

A 4.0-mm arthroscope with a 30-degree angle is routinely used for posterior ankle arthroscopy.

 

For posterior ankle arthroscopy, a noninvasive distraction device can be used when the ankle joint has to be entered for the diagnosis and treatment of an intra-articular pathology.

 

A 4-mm chisel and a periosteal elevator may be needed during posterior arthroscopy for excision of osteophytes and ossicles.

 

Positioning

 

The patient is placed in a prone position. The patient should be placed properly to avoid tension on the brachial plexi, avoid pressure on the ulnar nerve at the elbow, and protect the genitalia.

 

A tourniquet is applied around the upper leg, and a small support is placed under the lower leg, making it possible to move the ankle freely (FIG 3).

 

 

18

 

 

 

FIG 4 • Posterior (A), posteromedial (B), and posterolateral (C) views of foot and ankle with the cutaneous landmarks for posterior ankle arthroscopy and hindfoot endoscopy. 1, Achilles tendon; 2, lateral malleolus; 3, medial malleolus; asterisk, posterolateral portal; double asterisks, posteromedial portal.

 

 

The foot is placed at the very end of the operating table so that the surgeon can fully dorsiflex the ankle.

 

Approach

 

The landmarks on the ankle are the lateral malleolus, medial and lateral border of the Achilles tendon, and the sole of the foot. With a marking pen, a line is drawn as a reference from the tip of the lateral malleolus to the Achilles tendon, parallel to the sole of the foot.

 

Posterolateral and posteromedial portals are made just above this line, at the same level in the horizontal plane,

and just lateral and medial to the Achilles tendon (FIG 4).

TECHNIQUES

• Creation of the Posterolateral Portal

A vertical stab incision is made for posterolateral portal.

The subcutaneous layer is split by a mosquito clamp that is directed anteriorly in the direction of the interdigital web space between the first and second toes (TECH FIG 1A).

When the tip of the clamp touches the bone, it is exchanged for a 4.5-mm arthroscope shaft with the blunt trocar pointing in the same direction (TECH FIG 1B).

The level of the ankle joint and subtalar joint can be distinguished by palpating the bone in the sagittal plane because the prominent posterior talar process or os trigonum can be felt as a posterior prominence between the two joints.

The trocar is positioned extra-articularly at the level of the ankle joint.

The trocar is exchanged for the 4-mm arthroscope; the direction of view is 30 degrees to the lateral side.

 

 

 

 

TECH FIG 1 • Creation of the posterolateral portal. A. Subcutaneous tissue is dissected by a mosquito clamp in the direction of the first interdigital web space. B. When the tip of the clamp touches the posterior talar process, it is exchanged for a 4.5-mm arthroscope shaft with the blunt trocar pointing in the same direction.

• Creation of the Posteromedial Portal

   

  A vertical stab incision is made for the posteromedial portal.

   

  A mosquito clamp is introduced and directed toward the arthroscope shaft at a 90-degree angle (TECH FIG 2A).

   

  When the mosquito clamp touches the shaft of the arthroscope, the shaft is used as a guide for the clamp to move anteriorly in the direction of the ankle joint, touching the arthroscope shaft until it reaches the bone (TECH FIG 2B).

   

  Next, the arthroscope is withdrawn slightly, directly over the mosquito clamp until the tip of the mosquito clamp is visualized (TECH FIG 2C).

   

  The clamp is used to spread the extra-articular soft tissue in front of the tip of the lens.

   

  In situations in which scar tissue or adhesions are present, the mosquito clamp is exchanged for a 5-mm full-radius shaver.

   

  The tip of the shaver is directed in a lateral and slightly plantar direction toward the posterolateral aspect of the subtalar joint.

   

  When the tip of the shaver has reached this position, shaving can begin.

   

   

  19

   

   

   

  TECH FIG 2 • Creation of the posteromedial portal. A. A mosquito clamp is introduced and directed toward the arthroscope shaft at a 90-degree angle. B. Touching the arthroscope shaft, the mosquito clamp is slid anteriorly until it reaches the bone. C. The arthroscope is now withdrawn slightly and slides over the mosquito clamp until the tip of the mosquito clamp comes into view.

• Working Posterior to the Ankle

   

  The joint capsule and adipose tissue can be removed. The adipose tissue is removed first and with it the very thin joint capsule.

   

  The subtalar joint can now be recognized. The posterior talar fibular ligament that attaches to the talus at this level can be recognized as well.

   

  After removal of the thin joint capsule, the posterior subtalar joint can be inspected (TECH FIG 3A).

   

  At the level of the ankle joint, the posterior tibiofibular and talofibular ligaments are identified and the posterior ankle joint can be visualized (TECH FIG 3B).

   

   

   

  TECH FIG 3 • A. Arthroscopic views of the posterior compartment of the subtalar joint showing the calcaneus

  (A) and the talus (B). B. Endoscopic overview of the posterolateral aspect of the ankle joint. Os trigonum (OT) and its connection to the posterior talofibular ligament (PTFL). C. Application of the soft tissue distractor.

   

   

  The posterior talar process can be freed of scar tissue, and the FHL tendon, an important landmark, is identified. Motion of the hallux helps isolate the fibers of the FHL tendon in the posterior ankle.

   

  The shaver should never be used medial to the FHL tendon because of the proximity of the posteromedial neurovascular bundle.

   

  After removal of the thin posterior ankle joint capsule, the ankle joint is entered with the arthroscope and inspected.

   

  On the medial side, both the tip of the medial malleolus and the deep portion of the deltoid ligament are visualized.

   

  20

   

  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.

   

  With manual distraction on the os calcis, the posterior aspect of the ankle joint is opened, and the shaver can be introduced into the tibiotalar joint.

   

  For greater distraction, a noninvasive ankle distractor can be applied (TECH FIG 3C).

   

   

   

  TECH FIG 4 • Endoscopic procedure for débridement and drilling of a subtalar osteochondral cyst lesion in a right ankle (same patient as in FIG 2). A. Endoscopic image with an arrow indicating the defect. B. A hook is introduced via the posteromedial portal and penetrates the osteochondral defect up to the cyst. C. By retrograde drilling, the cyst is reached. The hook is used for guiding the exact direction of the drill. D. Postoperative overview.

   

   

  A total synovectomy or capsulectomy can be performed. In our experience, nearly the entire talar dome tibial plafond can be visualized via this posterior approach.

   

  An osteochondral defect or subchondral cystic lesion can be identified, débrided, and drilled (TECH FIG 4).

• Removal of an Os Trigonum

   

  The posterior syndesmotic ligaments are inspected and, if hypertrophic, are partially resected.

   

  Removal of a symptomatic os trigonum (TECH FIG 5), a nonunited fracture of the posterior talar process, or a symptomatic large posterior talar prominence requires partial detachment of the posterior talofibular ligament and release of the flexor retinaculum, both of which attach to the posterior talar prominence.

   

  21

   

   

   

  TECH FIG 5 • Endoscopic procedure for removing an os trigonum and releasing the FHL in a left ankle. A. Os trigonum (OT) with its connection to the posterior talofibular ligament (PTFL), flexor retinaculum, and talocalcaneal ligament (TCL). B. Cutting through the flexor retinaculum. C. Cutting through the TCL. D. Releasing the PTFL. E. Overview of the os trigonum released from its related anatomic structures. F. Postoperative overview. IML, intermalleolar ligament.

• Release of the Flexor Hallucis Longus Tendon

   

  Release of the FHL tendon involves detachment of the flexor retinaculum from the posterior talar process by means of a punch (TECH FIG 6).

   

  A tight, thick crural fascia, if present, can hinder the free movement of instruments. It is helpful to enlarge the hole in the fascia using a punch or shaver.

   

  Bleeding is controlled by electrocautery at the end of the procedure.

   

   

  22

   

  TECH FIG 6 • Endoscopic procedure for releasing of the FHL tendon (B) involves detachment of the flexor retinaculum (C) from the posterior talar process (A) by means of a punch. D, talus; E, subtalar joint.

  • Wound Closure and Dressing

  After removal of the instruments, the stab incisions are closed with 3-0 nylon to prevent sinus formation. A sterile compression dressing is applied.

  In patients with combined anterior and posterior symptoms, the posterior pathology is addressed by means of the two-portal hindfoot approach, and the anterior pathology is approached by a two-portal anterior approach.

  This can be done in two ways. The anterior arthroscopy can be performed with the knee flexed and the foot upside down, but we typically prefer a two-stage procedure. First, the two-portal hindfoot approach is finished. The patient is then turned and a routine anterior ankle arthroscopy is performed.

   

   

   

   

  PEARLS AND PITFALLS

   

  Position of the arthroscope

  • The direction of view should always be lateral.

     

    Rouvière ligament ▪ This ligament runs to the FHL retinaculum.

    • It can be attached to the posterior talar process.

    • An arthroscopic punch or scissors can be used to enlarge the entry through this ligament.

    • Usually, it has to be detached from the posterior talar process to get to the ankle joint.

       

      Safe areas ▪ The arthroscope should point into the direction of the web space between the first and second toes.

    • It should be positioned lateral to the FHL tendon. It can be positioned medial to the FHL tendon only when a release of the neurovascular bundle is required (posttraumatic tarsal tunnel syndrome).

 

Removing the ▪ Care should be taken not to place the chisel too far anterior, so as to avoid

 

 

hypertrophic posterior talar process using the chisel

entering the subtalar joint (FIG 5).

 

FIG 5 • A,B. Removal of the hypertrophic posterior talar process using the chisel. Care should be taken not to place the chisel too far anterior, so as to avoid entering the subtalar joint. FHL, flexor hallucis longus; OT, os trigonum.

 

How to initially visualize or gain proper orientation in the posterior ankle

• The most important trick is to start shaving at the level of the subtalar joint on the lateral side. This is an area in which it is relatively safe to start shaving. The opening of the shaver is directed toward the joint.

• Once the subtalar joint has been identified, the posterior talofibular ligament is identified. This ligament attaches to the lateral surface of the talus in this area.

• If we move the scope and shaver proximal from the posterior fibular ligament, we are at the level of the os trigonum. The soft tissue in this posterolateral area can now be removed.

• The ankle joint usually can now be identified by applying some traction to the calcaneus. Dorsiflexing the foot can also help.

• Part of the posterior ligaments can be removed to enter the ankle joint when desired.

• From the posterolateral corner, the instruments now can be moved over the posterior talar process or os trigonum to the medial side, while staying in contact with the posterior ankle ligaments and the proximal surface of the os trigonum all the way. The FHL then comes into view.

 

 

 

POSTOPERATIVE CARE

23

 

As soon as possible after surgery, the patient is advised to start range-of-motion exercises as tolerated. It is not necessary to immobilize the ankle postoperatively to prevent sinus formation. The posterior ankle joint has a good soft tissue covering. The advantage of the procedure is that patients can start to move the ankle directly postoperatively.

 

 

Postoperatively for 2 or 3 days, the patient is allowed weight bearing on crutches as tolerated. The dressing can be removed after 3 days. We remove the sutures 2 weeks postoperatively.

 

The patient is reevaluated 1 week postoperatively. If necessary, physical therapy can be prescribed for range of

motion, strengthening, and stability.

 

OUTCOMES

 

In a consecutive series of 146 posterior ankle arthroscopies (136 patients) performed at the Academic Medical Center University of Amsterdam between 1994 and 2002, all patients were satisfied postoperatively. There were no complications other than two patients who experienced a small area of diminished sensation over the heel pad of the hindfoot.

 

The main indication was a posterior ankle impingement syndrome. Procedures, all carried out by the same surgeon, were as follows:

 

 

Removal of a bony impediment (os trigonum or hypertrophic posterior talar process; n = 52) Additional release of the FHL tendon (n = 37)

 

 

Removal of a soft tissue impediment by a shaver (n = 8) Isolated release of the FHL tendon (n = 7)

 

Débridement and drilling of an osteochondral defect at the posteromedial talar dome (n = 7), in the tibial plafond (n = 4), or in the posterolateral talar dome (n = 2)

 

Removal of calcifications (n = 5)

 

Total synovectomy (the knee was flexed and an anterior synovectomy was performed by means of the standard anterolateral and anteromedial approach; n = 9)

 

 

Arthroscopic débridement of degenerated subtalar joint (n = 10) Removal of a loose body from the subtalar joint (n = 1)

 

Curettage, drilling, and grafting of a large intraosseous talar ganglion (n = 3)

 

Combined procedures did not cause any technical problems and were successful in most patients. Patients who were treated for a bony impingement did better than patients who were treated for a soft tissue impingement.

 

None of these patients had deterioration of the result over time.19

 

Marumoto and Ferkel9 treated 11 patients with painful os trigonum by arthroscopic removal of the os trigonum. The average postoperative American Orthopaedic Foot and Ankle Society (AOFAS) scale was 86.4 points 3 years postoperatively.

 

Jerosch and Fadel4 applied the same treatment method to 10 patients with symptomatic os trigonum; 9 of them were symptom-free 4 weeks postoperatively, and the average AOFAS scale increased from 43 preoperatively to 87 at a mean follow-up time of 25 months. They observed no complications in these 10 patients.

 

Tey et al16 endoscopically treated 15 patients with posterior ankle impingement and reported that all but 1 patient (7%) improved at an average 3 years of follow-up.

 

Willits et al23 performed 24 posterior ankle arthroscopies with an indication of posterior ankle impingement. The average time to return to work was 1 month and to sports was 5.8 months. Mean score on the AOFAS scale was improved to 91 at a mean follow-up time of 32 months postoperatively.

 

Ögüt et al12,13 used the two-portal hindfoot endoscopy technique successfully in a variety of indications, including intraosseous cysts of talus, talar fracture, pigmented villonodular synovitis, synovial osteochondromatosis, talar osteochondral lesions, and peroneal tenosynovitis. FHL tenosynovitis and posterior ankle impingement syndrome were the most common indications. In their series of 60 feet, they noted only two complications (3.3%) of sural nerve damage.

 

 

 

COMPLICATIONS

Potential complications of this technique include tibial nerve and vascular injury, FHL tendon injury, and sural nerve injury.

To prevent sural nerve injury, it is important to create the posterolateral portal as described previously, close to the Achilles tendon, first making a stab incision and then continuing with blunt dissection by a mosquito clamp.

Avoiding the potential complications of working through a posteromedial portal, the trick is to angle the instrument (shaver, burr, punch) in the posteromedial portal at 90 degrees to the arthroscope shaft.

The arthroscope shaft subsequently is used as a guide for the instrument to travel into the direction of the joint. All the way, the mosquito clamp should be felt to touch the arthroscope shaft. In this manner, the neurovascular bundle is passed without problem.

24

Precise control of the aspirator and shaver is mandatory to prevent tibialis posterior nerve and vessel injury and to prevent damage to the FHL tendon. In areas close to the neurovascular bundle, the aspirator should be set to a minimum amount of suction.

In their case series of 189 ankles, Nickisch et al11 found the complication rate as 8.5% (16 ankles); four patients had plantar numbness, three had sural nerve dysesthesia, four had Achilles tendon tightness, two had complex regional pain syndrome, two had infection, and one had a cyst at the posteromedial portal.

We have applied this technique since 1994 without any complications other than two patients who experienced a small area of diminished sensation over the heel pad of the hindfoot.

When performed in the manner described earlier, hindfoot endoscopy is a safe and reliable method of diagnosing and treating a variety of posterior ankle problems.

The decision to treat posterior as well as anterior pathology is made preoperatively. If preoperatively it is decided to treat both anterior and posterior pathology, we start with addressing the posterior pathology by means of the two-portal hindfoot approach. After finishing the posterior procedure, the portals are sutured and the patient is turned and the anterior procedure is performed.

 

ACKNOWLEDGMENT

 

The authors would greatly like to thank P. A. J. de Leeuw from the Department of Orthopaedic Surgery in the Academic Medical Center in Amsterdam, The Netherlands, for providing all the images for this chapter.

 

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