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Subtalar arthroscopy techniques
SUBTALAR ARTHROSCOPY TECHNIQUES SHARON M. DREEBEN, MD
This article outlines the features of subtalar arthroscopy. The joint anatom?4 portal placement, and surgical techniques are described. Indications and complications are discussed. This is a brief overview of subtalar arthroscopy. KEY WORDS: arthroscopy, subtalar joint
Subtalar arthroscopy is in its infancy. The ability to diagnose and treat subtalar pathology through the arthroscope is just beginning. The learning curve is steep and fraught with potential hazards. Subtalar Arthroscopy was first described in the literature in 1985J Since 1985 there have been few anatomic, technical and clinical reports, but the number has been increasing. 2 Interest in arthroscopy of this joint has developed slowly because of the need for small, specialized instruments and advanced equipment. However, the ability to "scope" the subtalar joint is now at hand. As with most joints, the value of an arthroscopic versus an open procedure is in question. Advantages will be measured in postoperative morbidity parameters: closed versus open operative time, infection rate, complication rate, postoperative recovery time and postoperative pain.
INDICATIONS Subtalar arthroscopy may be applied as a diagnostic and often therapeutic tool. As with any other joint, the subtalar joint should be compartmentalized and examined. Instability may be evaluated, osteochondral lesions debrided, os trigonum fractures excised, and arthritic joints fused. Indications will grow with experience.
joint and spring ligament. The dividing axis through the subtalar joint consists of the sinus tarsi (soft area 2 cm anterior to the tip of the lateral malleolus), 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 ° lateral to the longitudinal axis of the foot, the capsule (thickened anteriorly by interosseous ligament), the posterior recess, the lateral recess (thickened laterally by calcaneofibular ligament), and convex calcaneous matching a concave talus.
SURGICAL SET UP The surgical set-up requires the following instrumentation (the size of the subtalar joint requires small equipment): (1) 18-gauge spinal needle, (2) 1.9 m m to 2.7 m m 30 ° shorthandled wide angle arthroscope, (3) small joint shavers, (4) small joint burrs, (5) distracter--bone a n d / o r soft tissue, and (6) high-flow irrigation. The patient may be positioned supine or laterally with a bolster under the foot at the edge of the table, with the fluroscan around the foot after sterile draping (Fig 1).
JOINT DISTRACTION CONTRAINDICATIONS Relative contraindications include edema, vascular insufficiency, poor skin quality, and reflex sympathetic dystrophy. The one absolute contraindication is soft tissue infection leading to a potential septic joint.
ANATOMY The anatomy of the subtalar joint is complex. 3 It is helpful to have a model at surgery. All pertinent anatomic features are listed here and have been well described in the literature. Keep in mind the posterior facet joint is convexconcave in shape. The anterior subtalar joint (talocalcaneonavicular joint) consists of the anterior facet, middle facet, talonavicular
Two forms of joint distraction may be used: soft tissue and bony. An assistant may be helpful in distracting the joint and demonstrating subtalar motion. If further distraction is necessarN distraction through the bone is helpful. Talocalcaneal distraction offers greater distraction of the joint, but may injure the lateral calcaneal branch of the sural nerve or fracture the talar neck or bod}~ and, for this reason, is not recommended.
SKIN MARKINGS FOR SUBTALAR ARTHROSCOPY To facilitate the surgery, marking out the skin portal placement is helpful (Fig 2).
PORTALS From private practice, San Diego, CA. Address reprint requests to Sharon M. Dreeben, MD, 7910 Frost Street, Suite 202, San Diego, CA 92123. Copyright © 1999 by W/.B. Saunders Company 1060-1872/99/0701-0008510.00/0
Four portals and several modifications of each portal have been described. A description of each is given along with the potential complications. The anterior lateral portal is made in the sinus tarsi 2 cm
Operative Techniques in Sports Medicine, Vol 7, No 1 (January), 1999: pp 41-44
41
Fig 1. Patient position.
Fig 3. Insufflation of joint. An 18-gauge needle in the anterior lateral portal to insufflate joint.
are approximately 2.5 cm distal to the tip of the medial malleolus.
anterior and I cm inferior to the tip of the lateral malleolus. Caution should be taken not to injure the dorsal intermediate branch of the superficial peroneal nerve. The inframalleolar portal is made anterior to the calcaneal fibular ligament. Caution should be taken not to injure the peroneal tendons. The posterior lateral portal is made I cm posterior and 1 cm proximal to the tip of the fibula. Caution should be taken not to injure the sural nerve, lesser saphenous vein, and peroneal tendons. The medial portal 4 is made in the sinus tarsi approximately 2 cm anterior to the tip of the lateral malleolus. A sharp trocar is introduced through the deep fascia. A dull trocar, aimed proximally in a 40 ° to 45 ° angle to the longitudinal axis of the foot, is guided gently through the tarsal canal to the medial skin surface. The foot is placed in equinus to relax the medial neurovascular structures. An incision is made over trocar. The trocar is sleeved and the dull trocar introduced from the medial portal. The joint is insuffiated and the arthroscope is introduced to view the anterior lateral and posterior medial subtalar joint. Caution is taken to avoid the neurovascular structures, which
Insuffiate the joint by placing an 18-gauge or spinal needle with 10 CC saline into the sinus tarsi (Fig 3). The inflow may then be introduced through an 18-gauge or spinal needle in the inframalleolar or posterior portal. Inflow may also be established through the arthroscopic cannula. The anterior lateral portal is made in the sinus tarsi, 2 cm anterior and 1 cm inferior to the tip of the lateral malleolus. A small incision is made with a No. 11 blade. Blunt dissection by hemostat is performed down to the joint capsule. A dull probe is used to carefully puncture the capsule. The arthroscope is introduced into the subtalar joint (Fig 4). A fluroscan is used to confirm the placement (Fig 5). An outflow cannula is placed in the posterior lateral portal (Fig 6). If visualization is difficult, a soft tissue distractor may be used (Fig 7). A systematic examination of the subtalar joint is performed by varying the portal placement of the arthroscope. An arthroscope in the anterior lateral portal enables evalu-
Fig 2. Arthroscopic portals. ATFL, anterior talofibular ligament; CFL, calcaneofibular ligament; PTFL, posterior talofibular ligament.
Fig 4. Introducing scope. The arthroscope in the anterior portal perpendicular to the long axis of the foot. Inflow is connected to cannula.
42
INTRODUCTION OF THE ARTHROSCOPE
SHARON M. DREEBEN
Fig 5. Fluroscopic confirmation. Lateral radiograph of the foot with a portable fluroscanner confirming subtalar placement of the arthroscope.
Fig 7. Distraction. A small femoral distractor is applied laterally if there is significant difficulty visualizing the subtalar joint.
DISCUSSION ation of the sinus tarsi, interosseous ligament, cervical ligament, and lateral and posterior gutters. 8 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.
COMPLICATIONS 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. It is very easy to become disoriented while arthroscoping a subtalar joint. The arthroscope may be placed inadvertently in the ankle joint or penetrate the capsule of the ankle and enter the lateral ankle gutter. For this reason, fluoroscopic confirmation of position is useful.
Fig 6. Outflow. Outflow is established with a spinal needle in the posterior lateral portal. This portal is also used for instrumentation. SUBTALAR ARTHROSCOPY TECHNIQUES
Arthroscopy of the subtalar complex is an intriguing endeavor. The initial approach to the joint is actually an endoscopy. Within the soft tissues of the sinus tarsi the cervical ligament, interosseous ligament may be identified. The middle facet is seen only after removing the cervical ligament that it hides behind. When the scope has passed the anterior capsule, the arthroscopy into the posterior facet joint begins. The difficulty in penetrating the capsule and entering the joint is variable. The greater the laxity of the soft tissues and capsule, the easier to distract the joint and the more space is available for instruments. It is paramount in these cases not to disrupt the articular cartilage with instruments. Joints with arthritis may be scoped with less attention to the cartilage, because an arthroscopic fusion may conclude the procedure. However, these arthritic, stiff joints with a thick, scarred down capsule are very difficult to enter. Whatever the case, allow twice your expected operative time and confirm placement with the fluroscan often. Begin with the lateral portals.
Fig 8. Probe in the lateral gutter of the subtalar joint.
43
Medial portal p l a c e m e n t is fraught w i t h complications a n d should be p e r f o r m e d only b y experienced surgeons.
CONCLUSION A r t h r o s c o p y of the subtalar joint will evolve over the next decade. At this time, there is a steep learning curve a n d limited application. As technology d e v e l o p s and surgical p r o w e s s increases, so will the acceptance of this procedure.
44
REFERENCES 1. Parisien JS, Vanganess T:Arthroscopy of the subtler joint: An experimental approach. Arthroscopy 1:53-57, 1985 2. Frey C, Gasser S, Feder K: Arthroscopy of the subtler joint. Foot Ankle 16:424428, 1994 3. Sarafian SK (ed): Osteology, in Anatomy of the Foot and Ankle. New York, J.B. Lippincott, 1983, p 58 4. Mekhail AO, Heck BE, Ebraheim NA, et al: Arthroscopy of the subtler joint: Establishing a medial portal. Foot Ankle 16:427-432, 1995
SHARON M. DREEBEN
This article outlines the features of subtalar arthroscopy. The joint anatom?4 portal placement, and surgical techniques are described. Indications and complications are discussed. This is a brief overview of subtalar arthroscopy. KEY WORDS: arthroscopy, subtalar joint
Subtalar arthroscopy is in its infancy. The ability to diagnose and treat subtalar pathology through the arthroscope is just beginning. The learning curve is steep and fraught with potential hazards. Subtalar Arthroscopy was first described in the literature in 1985J Since 1985 there have been few anatomic, technical and clinical reports, but the number has been increasing. 2 Interest in arthroscopy of this joint has developed slowly because of the need for small, specialized instruments and advanced equipment. However, the ability to "scope" the subtalar joint is now at hand. As with most joints, the value of an arthroscopic versus an open procedure is in question. Advantages will be measured in postoperative morbidity parameters: closed versus open operative time, infection rate, complication rate, postoperative recovery time and postoperative pain.
INDICATIONS Subtalar arthroscopy may be applied as a diagnostic and often therapeutic tool. As with any other joint, the subtalar joint should be compartmentalized and examined. Instability may be evaluated, osteochondral lesions debrided, os trigonum fractures excised, and arthritic joints fused. Indications will grow with experience.
joint and spring ligament. The dividing axis through the subtalar joint consists of the sinus tarsi (soft area 2 cm anterior to the tip of the lateral malleolus), 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 ° lateral to the longitudinal axis of the foot, the capsule (thickened anteriorly by interosseous ligament), the posterior recess, the lateral recess (thickened laterally by calcaneofibular ligament), and convex calcaneous matching a concave talus.
SURGICAL SET UP The surgical set-up requires the following instrumentation (the size of the subtalar joint requires small equipment): (1) 18-gauge spinal needle, (2) 1.9 m m to 2.7 m m 30 ° shorthandled wide angle arthroscope, (3) small joint shavers, (4) small joint burrs, (5) distracter--bone a n d / o r soft tissue, and (6) high-flow irrigation. The patient may be positioned supine or laterally with a bolster under the foot at the edge of the table, with the fluroscan around the foot after sterile draping (Fig 1).
JOINT DISTRACTION CONTRAINDICATIONS Relative contraindications include edema, vascular insufficiency, poor skin quality, and reflex sympathetic dystrophy. The one absolute contraindication is soft tissue infection leading to a potential septic joint.
ANATOMY The anatomy of the subtalar joint is complex. 3 It is helpful to have a model at surgery. All pertinent anatomic features are listed here and have been well described in the literature. Keep in mind the posterior facet joint is convexconcave in shape. The anterior subtalar joint (talocalcaneonavicular joint) consists of the anterior facet, middle facet, talonavicular
Two forms of joint distraction may be used: soft tissue and bony. An assistant may be helpful in distracting the joint and demonstrating subtalar motion. If further distraction is necessarN distraction through the bone is helpful. Talocalcaneal distraction offers greater distraction of the joint, but may injure the lateral calcaneal branch of the sural nerve or fracture the talar neck or bod}~ and, for this reason, is not recommended.
SKIN MARKINGS FOR SUBTALAR ARTHROSCOPY To facilitate the surgery, marking out the skin portal placement is helpful (Fig 2).
PORTALS From private practice, San Diego, CA. Address reprint requests to Sharon M. Dreeben, MD, 7910 Frost Street, Suite 202, San Diego, CA 92123. Copyright © 1999 by W/.B. Saunders Company 1060-1872/99/0701-0008510.00/0
Four portals and several modifications of each portal have been described. A description of each is given along with the potential complications. The anterior lateral portal is made in the sinus tarsi 2 cm
Operative Techniques in Sports Medicine, Vol 7, No 1 (January), 1999: pp 41-44
41
Fig 1. Patient position.
Fig 3. Insufflation of joint. An 18-gauge needle in the anterior lateral portal to insufflate joint.
are approximately 2.5 cm distal to the tip of the medial malleolus.
anterior and I cm inferior to the tip of the lateral malleolus. Caution should be taken not to injure the dorsal intermediate branch of the superficial peroneal nerve. The inframalleolar portal is made anterior to the calcaneal fibular ligament. Caution should be taken not to injure the peroneal tendons. The posterior lateral portal is made I cm posterior and 1 cm proximal to the tip of the fibula. Caution should be taken not to injure the sural nerve, lesser saphenous vein, and peroneal tendons. The medial portal 4 is made in the sinus tarsi approximately 2 cm anterior to the tip of the lateral malleolus. A sharp trocar is introduced through the deep fascia. A dull trocar, aimed proximally in a 40 ° to 45 ° angle to the longitudinal axis of the foot, is guided gently through the tarsal canal to the medial skin surface. The foot is placed in equinus to relax the medial neurovascular structures. An incision is made over trocar. The trocar is sleeved and the dull trocar introduced from the medial portal. The joint is insuffiated and the arthroscope is introduced to view the anterior lateral and posterior medial subtalar joint. Caution is taken to avoid the neurovascular structures, which
Insuffiate the joint by placing an 18-gauge or spinal needle with 10 CC saline into the sinus tarsi (Fig 3). The inflow may then be introduced through an 18-gauge or spinal needle in the inframalleolar or posterior portal. Inflow may also be established through the arthroscopic cannula. The anterior lateral portal is made in the sinus tarsi, 2 cm anterior and 1 cm inferior to the tip of the lateral malleolus. A small incision is made with a No. 11 blade. Blunt dissection by hemostat is performed down to the joint capsule. A dull probe is used to carefully puncture the capsule. The arthroscope is introduced into the subtalar joint (Fig 4). A fluroscan is used to confirm the placement (Fig 5). An outflow cannula is placed in the posterior lateral portal (Fig 6). If visualization is difficult, a soft tissue distractor may be used (Fig 7). A systematic examination of the subtalar joint is performed by varying the portal placement of the arthroscope. An arthroscope in the anterior lateral portal enables evalu-
Fig 2. Arthroscopic portals. ATFL, anterior talofibular ligament; CFL, calcaneofibular ligament; PTFL, posterior talofibular ligament.
Fig 4. Introducing scope. The arthroscope in the anterior portal perpendicular to the long axis of the foot. Inflow is connected to cannula.
42
INTRODUCTION OF THE ARTHROSCOPE
SHARON M. DREEBEN
Fig 5. Fluroscopic confirmation. Lateral radiograph of the foot with a portable fluroscanner confirming subtalar placement of the arthroscope.
Fig 7. Distraction. A small femoral distractor is applied laterally if there is significant difficulty visualizing the subtalar joint.
DISCUSSION ation of the sinus tarsi, interosseous ligament, cervical ligament, and lateral and posterior gutters. 8 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.
COMPLICATIONS 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. It is very easy to become disoriented while arthroscoping a subtalar joint. The arthroscope may be placed inadvertently in the ankle joint or penetrate the capsule of the ankle and enter the lateral ankle gutter. For this reason, fluoroscopic confirmation of position is useful.
Fig 6. Outflow. Outflow is established with a spinal needle in the posterior lateral portal. This portal is also used for instrumentation. SUBTALAR ARTHROSCOPY TECHNIQUES
Arthroscopy of the subtalar complex is an intriguing endeavor. The initial approach to the joint is actually an endoscopy. Within the soft tissues of the sinus tarsi the cervical ligament, interosseous ligament may be identified. The middle facet is seen only after removing the cervical ligament that it hides behind. When the scope has passed the anterior capsule, the arthroscopy into the posterior facet joint begins. The difficulty in penetrating the capsule and entering the joint is variable. The greater the laxity of the soft tissues and capsule, the easier to distract the joint and the more space is available for instruments. It is paramount in these cases not to disrupt the articular cartilage with instruments. Joints with arthritis may be scoped with less attention to the cartilage, because an arthroscopic fusion may conclude the procedure. However, these arthritic, stiff joints with a thick, scarred down capsule are very difficult to enter. Whatever the case, allow twice your expected operative time and confirm placement with the fluroscan often. Begin with the lateral portals.
Fig 8. Probe in the lateral gutter of the subtalar joint.
43
Medial portal p l a c e m e n t is fraught w i t h complications a n d should be p e r f o r m e d only b y experienced surgeons.
CONCLUSION A r t h r o s c o p y of the subtalar joint will evolve over the next decade. At this time, there is a steep learning curve a n d limited application. As technology d e v e l o p s and surgical p r o w e s s increases, so will the acceptance of this procedure.
44
REFERENCES 1. Parisien JS, Vanganess T:Arthroscopy of the subtler joint: An experimental approach. Arthroscopy 1:53-57, 1985 2. Frey C, Gasser S, Feder K: Arthroscopy of the subtler joint. Foot Ankle 16:424428, 1994 3. Sarafian SK (ed): Osteology, in Anatomy of the Foot and Ankle. New York, J.B. Lippincott, 1983, p 58 4. Mekhail AO, Heck BE, Ebraheim NA, et al: Arthroscopy of the subtler joint: Establishing a medial portal. Foot Ankle 16:427-432, 1995
SHARON M. DREEBEN