General Considerations
The procedure is carried out in an outpatient setting with the patient under general or spinal anesthesia. The affected side is carefully marked preoperatively, and the patient is placed in a prone position. Prophylactic antibiotics are not routinely administered. A tourniquet is applied proximal to the knee and is inflated to a pressure of 300 mm Hg prior to instrument insertion. The ankle is positioned slightly over the distal edge of the operating table with a small triangular support under the distal part of the leg, allowing free movement of the ankle (Fig. 1). Normal saline solution or Ringer solution is used for irrigation; the flow is obtained by gravity. Typically, a 4.0-mm 30° arthroscope is used. Distraction is not routinely applied, but soft-tissue distraction may be used when indicated7.
Portal Placement
The anatomical landmarks for portal placement are the sole of the foot, the lateral malleolus, and the medial and lateral borders of the Achilles tendon. With the ankle in the neutral position (90°), a straight line, parallel to the sole of the foot, is drawn from the tip of the lateral malleolus to the Achilles tendon and is extended over the Achilles tendon to the medial side.
The posterolateral portal is located just proximal to, and 5 mm anterior to, the intersection of the straight line with the lateral border of the Achilles tendon. The posteromedial portal is located at the same level as the posterolateral portal, but on the medial side of the Achilles tendon (Figs. 2-A and 2-B).
Instrument Introduction
The posterolateral portal is made as a vertical stab incision, and the subcutaneous layer is spread with a mosquito clamp. The foot is now in a slightly (relaxed) plantar-flexed position. The clamp is directed anteriorly, toward the web space between the first and second toes (Fig. 3-A). When the tip of the clamp touches bone, it is exchanged for a 4.5-mm arthroscopic cannula, with the blunt trocar pointing in the same direction (Fig. 3-B). The trocar is situated extra-articularly at the level of the posterior talar process and is exchanged for the 4.0-mm 30° arthroscope, directed laterally (Fig. 3-C). At this time, the arthroscope is still outside the joint with its tip in the fatty tissue overlying the capsule.
Next, the posteromedial portal is made with a vertical stab incision, and a mosquito clamp is introduced through the stab incision and is directed toward the arthroscope shaft at a right angle until the clamp contacts the arthroscope (Fig. 3-D). The ankle is still in a slightly plantar-flexed position, and the arthroscope has remained in position through the posterolateral portal, directed toward the first web space. The arthroscope shaft is used as a guide for the mosquito clamp to travel anteriorly. While in contact with the arthroscope shaft, the clamp glides over the shaft toward the ankle joint until bone is reached (Fig. 3-E). Once the arthroscope and clamp are both touching bone, the mosquito clamp is left in position and the arthroscope is pulled slightly backward (Fig. 3-F) and is tilted until the tip of the clamp comes into view (Fig. 3-G). The soft-tissue layer covering the joints consists of fatty tissue and the deep crural fascia. At the lateral side a specialized part of the crural fascia can be recognized, which is called the Rouvière ligament.
Exchanging instruments through the posteromedial portal requires a careful step-by-step procedure. The described position of the arthroscope pointing in the direction of the first web space with the ankle in slight plantar flexion is always the starting point. Instruments introduced through the posteromedial portal are inserted perpendicular to the arthroscope until they are in contact. Subsequently, the arthroscopic shaft is routinely used to guide any instrument, introduced through the posteromedial portal, toward the posterior parts of the ankle and subtalar joints. For the correct orientation, the arthroscope is always directed to the lateral side.
Surgical Procedure and Addressing the Pathology
The clamp is now directed to the lateral side in an anterior and slightly plantar direction. This movement creates an opening in the crural fascia, just lateral to the posterior talar process. The fatty tissue and the subtalar joint capsule are subsequently opened. The mosquito clamp is then exchanged for a 5-mm full-radius shaver (Fig. 3-H). With a few turns of the shaver, the subtalar joint capsule and the soft tissue are gently removed (Fig. 4, A). The opening of the shaver blade is facing bone. This part of the procedure is carried out in a blind fashion. The shaver is then retracted (Fig. 4, B), and the arthroscope is brought anteriorly (as shown in Figure 5) through the opening in the crural fascia to visualize the posterolateral aspect of the subtalar joint (Fig. 4, C). Once the joint is recognized, the opening in the crural fascia is enlarged to create more working area.
Figure 5 shows a schematic representation of the steps described above.
The cranial part of the posterior talar process is freed from the Rouvière ligament and crural fascia (Fig. 6, A, B, and C) to identify the flexor hallucis longus tendon (Fig. 6, D). The flexor hallucis longus tendon is an important safety landmark. Since the neurovascular bundle runs just medial to this tendon, the area lateral to the flexor hallucis longus tendon is regarded as being safe.
At the level of the ankle joint, the posterior talofibular ligament is identified. Proximally, the intermalleolar ligament, also called the tibial slip, and the deep portion of the posterior tibiofibular ligament, also called the transverse ligament, are identified in turn (Fig. 6, D). A distinction between these ligaments can easily be made by dorsiflexion of the ankle8. The intermalleolar and transverse ligaments can be elevated with a probe in order to enter and inspect the ankle joint.
In the case of isolated flexor hallucis longus tendinitis, the flexor retinaculum can be released by detaching it from the posterior talar process or symptomatic os trigonum with an arthroscopic punch. Subsequently, the tendon sheath can be opened up to the level of the sustentaculum tali and entered with the arthroscope, allowing accurate tendon inspection. The proximal part of the tendon and the distal part of the muscle belly are inspected and débrided if inflamed or thickened or if nodules are present. Adhesions and excessive scar tissue are removed with a shaver; however, a radiofrequency probe may also be used. Under all circumstances, care is required due to the proximity of the neurovascular bundle.
Removal of a symptomatic os trigonum, an ununited fracture of the posterior talar process, or a symptomatic large posterior talar prominence involves partial detachment of the posterior talofibular ligament, detachment of the talocalcaneal ligament, and release of the flexor retinaculum (Fig. 6, E). All of these structures attach to the posterior talar prominence or symptomatic os trigonum, and the release of each is ideally performed with an arthroscopic punch or scissors (Fig. 6, F and G). The posterior talofibular ligament can also be detached with a shaver. After release of these structures (Fig. 6, H), a small blunt periosteal elevator with a curved tip is best suited to detach the os trigonum from the talus (Fig. 6,I and J). It can be applied both proximally and distally. A chisel is used to detach a symptomatic enlarged posterior talar process. Caution is required in relation to the position of the chisel, which should not be placed too far anteriorly, in order to avoid entering the subtalar joint.
With the application of manual traction to the calcaneus, the posterior compartment of the ankle is distracted and the arthroscope and a probe or shaver can be easily introduced into the ankle joint. We prefer to apply a soft-tissue distractor at this point7. A synovectomy and/or capsulectomy can be performed when indicated. The talar dome as well as the complete tibial plafond can be inspected over almost their entire surface. An osteochondral defect or subchondral cystic lesion can be identified and débrided, and microfracture can be performed. The posterior syndesmotic ligaments are inspected and are débrided if fibrotic or ruptured. Syndesmotic stability can be tested with a hook, and loose bodies in the syndesmotic ligament complex can be released and subsequently removed.
On the medial side, the tip of the medial malleolus and the deep portion of the deltoid ligament can be visualized. Opening the joint capsule from inside out at the level of the medial malleolus can allow the posterior tibial tendon sheath to be opened as desired. Subsequently, the arthroscope can be introduced into the tendon sheath to inspect the posterior tibial tendon.
Bleeding is controlled by means of electrocautery at the end of the procedure. To prevent sinus formation, the skin incisions are sutured with 3.0 nylon. The incisions and surrounding skin are injected with 10 mL of a 0.5% bupivacaine-morphine solution. A sterile compressive dressing is applied.
INDICATIONS:
The indications can be categorized according to their anatomical orientation.
ArticularOsseous pathology includes loose bodies, ossicles, posttraumatic calcifications, avulsion fragments, and osteophytes. The osteophytes can be located either at the posterior tibial rim or at the level of the subtalar joint.Cartilage pathology includes chondromatosis; posterior talar, tibial, or calcaneal osteochondral defects; degenerativejoint changes such as talar cystic lesions; bone spurs; and intraosseous talar ganglia.Soft-tissue pathology includes posttraumatic synovitis, villonodular synovitis, and syndesmotic soft-tissue impingement.
Osseous pathology includes loose bodies, ossicles, posttraumatic calcifications, avulsion fragments, and osteophytes. The osteophytes can be located either at the posterior tibial rim or at the level of the subtalar joint.
Cartilage pathology includes chondromatosis; posterior talar, tibial, or calcaneal osteochondral defects; degenerativejoint changes such as talar cystic lesions; bone spurs; and intraosseous talar ganglia.
Soft-tissue pathology includes posttraumatic synovitis, villonodular synovitis, and syndesmotic soft-tissue impingement.
PeriarticularPosterior ankle impingement (osseous and/or soft-tissue impingement). Osseous impingement includes a hypertrophic posterior talar process, an os trigonum, or a talus bipartita. Soft-tissue impingement includes a partial rupture or fibrosis of the posterior talofibular ligament, the intermalleolar ligament, or the deep portion of the posterior tibiofibuiar ligament.Avulsion fragments (Cedell fracture) and posttraumatic calcifications or ossicles in the deep portion of the deltoid ligament.Flexor hallucis longus tendinopathy.Recurrent peroneal tendon dislocation.
Posterior ankle impingement (osseous and/or soft-tissue impingement). Osseous impingement includes a hypertrophic posterior talar process, an os trigonum, or a talus bipartita. Soft-tissue impingement includes a partial rupture or fibrosis of the posterior talofibular ligament, the intermalleolar ligament, or the deep portion of the posterior tibiofibuiar ligament.
Avulsion fragments (Cedell fracture) and posttraumatic calcifications or ossicles in the deep portion of the deltoid ligament.
Flexor hallucis longus tendinopathy.
Recurrent peroneal tendon dislocation.
Procedures include removal of osseous and/or soft-tissue impediments, synovectomy, débridement of an osteochondral defect, retrograde drilling of large cystic lesions, arthroscopically assisted arthrodesis, and groove deepening for the treatment of recurrent peroneal tendon dislocation.
CONTRAINDICATIONS:The absolute contraindication is a localized soft-tissue infection.Relative contraindications are severe edema, vascular diseases (including diabetic vascular disease), and moderate degenerative joint disease.
The absolute contraindication is a localized soft-tissue infection.
Relative contraindications are severe edema, vascular diseases (including diabetic vascular disease), and moderate degenerative joint disease.
PITFALLS:Correct portal placement is important in order to prevent neurovascular complications. The posteromedial and posterolateral portals must be positioned 5 mm anterior to the Achilles tendon, just proximal to the level of the tip of the lateral malleolus.For the correct orientation and reproducibility, the procedure is begun with the arthroscope in the posterolateral portal. Initially, it is directed toward the first web space. Instruments introduced through the posteromedial portal are inserted perpendicular to the arthroscopic shaft. The shaft is subsequently used as a guide to direct the instruments anteriorly.In the hindfoot, the crural fascia can be quite thick. This local thickening is called the ligament of Rouvière. It needs to be at least partially excised or sectioned, with use of an arthroscopic punch or scissors, to approach the ankle joint.The flexor hallucis longus tendon must always be located before addressing the pathology. Medial to this tendon, the tibial nerve and the posterior tibial artery are situated. The working area is therefore lateral to the flexor hallucis longus tendon.The direction of the arthroscopic view (30° angulation) is routinely to the lateral side to provide a reproducible orientation throughout the procedure.Posterior ankle arthroscopy is an advanced endoscopic procedure; surgeons not familiar with endoscopic surgery are advised to practice in a cadaver setting9.
Correct portal placement is important in order to prevent neurovascular complications. The posteromedial and posterolateral portals must be positioned 5 mm anterior to the Achilles tendon, just proximal to the level of the tip of the lateral malleolus.
For the correct orientation and reproducibility, the procedure is begun with the arthroscope in the posterolateral portal. Initially, it is directed toward the first web space. Instruments introduced through the posteromedial portal are inserted perpendicular to the arthroscopic shaft. The shaft is subsequently used as a guide to direct the instruments anteriorly.
In the hindfoot, the crural fascia can be quite thick. This local thickening is called the ligament of Rouvière. It needs to be at least partially excised or sectioned, with use of an arthroscopic punch or scissors, to approach the ankle joint.
The flexor hallucis longus tendon must always be located before addressing the pathology. Medial to this tendon, the tibial nerve and the posterior tibial artery are situated. The working area is therefore lateral to the flexor hallucis longus tendon.
The direction of the arthroscopic view (30° angulation) is routinely to the lateral side to provide a reproducible orientation throughout the procedure.
Posterior ankle arthroscopy is an advanced endoscopic procedure; surgeons not familiar with endoscopic surgery are advised to practice in a cadaver setting9.
AUTHOR UPDATE:
Since our original paper was published, no substantial changes have been made in the surgical technique.