- Email: [email protected]
Fluoroscopic Method for Localization of the Anteromedial Portal for Use in Ankle Arthoscopy: Technique Tip
The Journal of Foot & Ankle Surgery 52 (2013) 257–259
Contents lists available at ScienceDirect
The Journal of Foot & Ankle Surgery journal homepage: www.jfas.org
Tips, Quips, and Pearls “Tips, Quips, and Pearls” is a special section in The Journal of Foot & Ankle SurgeryÒ, which is devoted to the sharing of ideas to make the practice of foot and ankle surgery easier. We invite our readers to share ideas with us in the form of special tips regarding diagnostic or surgical procedures, new devices or modifications of devices for making a surgical procedure a little bit easier, or virtually any other “pearl” that the reader believes will assist the foot and ankle surgeon in providing better care. Please address your tips to: D. Scot Malay, DPM, MSCE, FACFAS, Editor, The Journal of Foot & Ankle SurgeryÒ, PO Box 590595, San Francisco, CA 94159-0595; E-mail: [email protected]
Fluoroscopic Method for Localization of the Anteromedial Portal for Use in Ankle Arthoscopy: Technique Tip Richard L. Needleman, MD Assistant Professor, Department of Orthopaedic Surgery, Wayne State University, Dearborn, MI
a r t i c l e i n f o
a b s t r a c t
Keywords: arthroscope C-arm fluoroscopy joint capsule surgery talus tibia
Ankle arthroscopy has become a standard surgical technique for the treatment of many ankle pathologies. Over the past 30 years, the technique has undergone modification and standardization in order to improve surgical performance and outcomes. In contrast to the ankle joint, the hip joint is a deep joint, which makes visualization and palpation of the topographical anatomy quite difficult. The use of fluoroscopy has enabled the surgeon to successfully perform hip arthroscopy for the treatment of selective hip pathologies. Fluoroscopy also can improve the localization of the anteromedial portal for use in ankle arthroscopy. This technique is valuable for the less-experienced ankle arthroscopist, in resident education, and for the experienced arthroscopist when surface anatomy palpation and visualization is less than ideal due to soft tissue edema and obesity. Ó 2013 by the American College of Foot and Ankle Surgeons. All rights reserved.
Arthroscopy was first performed in 1918 in a cadaver knee (1). Improvements in technology have allowed for the development of smaller arthroscopes, better light sources, and instrumentation. A standard method for the examination of the ankle was first published in 1939 by Takagi (2). Watenabe (3) published his experience with ankle arthroscopy with a fiberoptic arthroscope in 1972. Initially, visualization and surgery were confined to anterior compartment lesions. It was difficult to visualize and access posterior compartment lesions. In recent years, ankle arthroscopic techniques have continued to advance to allow for improved visualization and surgical access to the ankle. The surgical technique has become much more standardized in regard to the equipment, positioning, distraction, and portals used (4). The anteromedial ankle portal enters the ankle joint between the notch of Harty (at the junction of the anterior tibial lip and the medial malleolus) and the talar dome just medial to the anterior tibial tendon and 0.5 to 1 cm distal to the joint line. The notch allows for a small arthroscope to be more easily passed to the posterior compartment of the ankle than by way of the anterolateral portal (5).
Financial Disclosure: None reported. Conflict of Interest: None reported. Address correspondence to: Richard L. Needleman, MD, Assistant Professor, Department of Orthopaedic Surgery, Wayne State University, 18100 Oakwood Boulevard, Suite 300, Dearborn, MI 48124. E-mail address: [email protected]
The standard technique for establishing the anteromedial ankle portal has been well described (4). The surgeon must have a clear understanding of the surface anatomy. The initial placement of the anteromedial ankle portal is dependent on accurate palpation and visualization of the topographic anatomy of the ankle. The visualization and palpation of the key anatomic structures can be less than ideal owing to soft tissue edema and obesity. A less-experienced ankle arthroscopist might have more difficulty understanding the surface anatomy than an experienced ankle arthroscopist in less than ideal conditions. The surgeon will attempt to find the best angle to direct the arthroscope into the tibiotalar joint anteriorly from either the anteromedial or anterolateral portals to perform a complete ankle arthroscopic evaluation, including the posterior compartment. In some cases, it could be difficult owing to the presence of anterior spurs or “tight ankles.” It is important to distract the ankle with enough force to allow for adequate visualization and surgical access. Adherence to the standardized surgical technique has been advised for improved visualization, for better surgical access, and to avoid complications. Strong emphasis has been placed on proper portal placement, proper portal entry technique to minimize articular cartilage scuffing, and proper placement of the padded foot strap and noninvasive ankle distractor. Excessive soft tissue distraction using a padded foot strap has been thought to contribute to nerve hypersensitivity to the dorsal part of the midfoot (6).
1067-2516/$ - see front matter Ó 2013 by the American College of Foot and Ankle Surgeons. All rights reserved. http://dx.doi.org/10.1053/j.jfas.2012.10.001
258
R.L. Needleman / The Journal of Foot & Ankle Surgery 52 (2013) 257–259
Fig. 1. Fluoroscopic set up.
As with any surgical procedure, evolutionary development toward a better technique is ongoing. Arthroscopy has been the benefactor of technological advances. The knee was the first joint to undergo arthroscopic evaluation because of its large size and location close to the skin. The surface anatomy was easy to palpate and understand. Other joints have followed, including smaller joints close to the skin (ankle and wrist) and joints deep to the skin (hip). Initially, arthroscopists had difficulty with the hip (a large joint deep to the skin) because of the difficulty in palpating key anatomic landmarks. A more successful approach to hip arthroscopy using C-arm fluoroscopy for proper portal placement and portal entry has improved visualization of the hip and reduced the risk of complications (7). Beals et al (8) described a technique for posterior ankle and hindfoot arthroscopy with the patient lying prone. The proper portal position is dependent on the location of the procedure to be performed. For example, a lower portal will facilitate posterior ankle arthroscopy. Mini–C-arm fluoroscopy has routinely been used to guide portal placement (8). The addition of mini–C-arm fluoroscopy to the standard supine ankle arthroscopy technique to obtain real-time intraoperative lateral images of the ankle joint during initial anteromedial portal placement can facilitate proper location of the anteromedial portal. This allows for the safe entrance of the arthroscope into the ankle using the optimal “entrance angle” with the least amount of noninvasive distraction to perform adequate visualization of both the anterior and the posterior compartments and reduce the risk of complications.
Fig. 2. Intraoperative fluoroscopic images showing localization of anteromedial portal. (A) Needle introduced into ankle joint by way of anteromedial portal. (B) Optimal “entrance angle” (q) determined to allow for easier passage of arthroscope to posterior compartment. Optimal “entrance angle” is angle between longitudinal axis of tibia (line) and axis of arthroscope (arrow). (C) Blunt 2.7-mm trocar placed into ankle joint along proper entrance angle. (D) The noninvasive distractor might need to be adjusted. Next, a blunt trocar is placed within a 2.9mm arthroscopic cannula into ankle joint along proper entrance angle.
R.L. Needleman / The Journal of Foot & Ankle Surgery 52 (2013) 257–259
Operative Technique Before inserting the arthroscope in the anteromedial portal, the joint should be carefully distracted with a soft tissue distraction strap and the external anatomic landmarks marked (saphenous vein and anterior tibial tendon). The initial placement of the anteromedial ankle portal depends on the accurate palpation and visualization of the topographic anatomy of the ankle. The key structures for palpation include the anterior tibial tendon (which is almost always palpable) and the anterior tibiotalar joint line (between the talar dome and the anterior tibial lip) medial to the anterior tibial tendon. The joint line is identified by palpation with dorsiflexion and plantarflexion of the ankle. The mini–C-arm is set up to obtain real-time intraoperative lateral images of the ankle joint (Fig. 1). The exact placement of this portal is located with a hypodermic or spinal needle just medial to the anterior tibial tendon and just distal to the tibiotalar joint line by about 0.5 to 1 cm. Next, one should introduce a needle into the ankle joint by way of the anteromedial portal with fluoroscopic assistance (Fig. 2A). The ankle joint is then distended with saline or lactated Ringer’s solution to facilitate placement of the arthroscope and minimize scuffing of the articular cartilage. The portal is placed using a “nick and spread” technique. The ”entrance angle” is determined to allow for safe passage of the arthroscope to the posterior compartment without any damage to the tendon or bone or scuffing of the articular joint cartilage. This angle is defined as the angle between the arthroscope (or instruments) and the longitudinal axis of the tibia (Fig. 2B). A blunt 2.7-mm trocar is placed into the ankle joint along the proper “entrance angle” (Fig. 2C) to dilate the portal. The noninvasive distractor is adjusted to allow for the least distraction force to perform this maneuver. The trocar is then removed and replaced with a blunt trocar within a 2.9-mm arthroscopic cannula into the ankle joint along the proper “entrance angle” (Fig. 2D). The noninvasive distractor is adjusted. The trocar is then removed, leaving the cannula in place. Finally, the arthroscope is inserted into the ankle by way of the cannula. Discussion Fluoroscopy has undergone many technical improvements, including portability and smaller machines. Fluoroscopic machines are frequently used by foot and ankle surgeons in the operating room during hip fracture surgery and intramedullary fixation of the long bones. With the advent of smaller portable units, hand and foot surgery has benefited, with better patient outcomes. With the development of arthroscopic techniques of the hip, fluoroscopy has been a critical factor because it allows the arthroscopist to access the hip joint with proper portal placement and portal entry. Adherence to the standardized surgical technique has been advised for improved visualization of the hip, better surgical access, and to avoid complications (7). With the use of fluoroscopy to assist with portal placement and portal entry during ankle arthroscopy, similar surgical success should be achieved. A small-diameter arthroscope can pass further into the ankle, with improved visualization of most of the articular surfaces of the talus and tibial plafond than with an arthroscope with a larger diameter (9). The “entrance angle” should conform to the natural curve of the talus and the matching curve of the tibial plafond. The presence of anterior spurs can contribute to a deepening of the concavity of the tibial plafond and
259
would therefore require more distraction to further separate the talus from the tibia. Excessive soft tissue distraction using a padded foot strap has been thought to contribute to nerve hypersensitivity to the dorsal part of the midfoot (6). To reduce the risk of this complication, it is advisable to use the least amount of noninvasive distraction necessary to allow for entrance of the arthroscope into the ankle to perform adequate visualization of the ankle, anteriorly and posteriorly. Intraoperative fluoroscopy can help the surgeon safely insert the arthroscope to visualize the posterior compartment without excessive distraction, lessening the forces on the dorsum of the foot. The proper placement of the anteromedial ankle portal under fluoroscopy can reduce complications by minimizing scuffing of the articular cartilage and achieving sufficient distraction to perform ankle arthroscopy while avoiding excessive distraction, minimizing the risk of possible cutaneous nerve injury. The optimization of the “entrance angle” improves visualization of the posterior ankle joint through verification of the passage of the cannula into the posterior compartment of the ankle. This technical modification will make ankle arthroscopy easier for less-experienced surgeons to perform with fewer complications and make it easier to instruct residents. Patients with poor external landmarks because of obesity and/or edematous ankles would qualify for minimal incision ankle arthroscopy instead of ankle arthrotomy, with the added benefits of better joint visualization and improved surgical technique. Ankle arthroscopy can also be attempted and successfully performed in those patients with large anterior ankle spurs, instead of ankle arthrotomy. Surgeons frequently perform supine ankle arthroscopy using the anteromedial and anterolateral portals. These portals are the basic portals for ankle arthroscopy. The posterolateral portal has been recommended as a portal dedicated to outflow or for visualization of a posteromedial talar lesion, anterior osteophyte, or loose body, with the anterior portals becoming the working portal and outflow portal. Although this portal is frequently cited in the standard surgery technique, most ankle arthroscopists have not embraced it, because it is more difficult to achieve proper portal placement and proper portal entry than the anterior portals. The anterior aspect of the ankle is closer to the skin, and the posterior aspect of the ankle is deeper to the skin. The surface anatomy of the posterior ankle is more difficult to delineate. Future studies will use the mini–C-arm to aid with proper posterolateral portal placement and proper portal entry technique for supine ankle arthroscopy. References 1. O’Connor RL. Arthroscopy, Upjohn, Kalamazoo, MI, 1977. pp 12–16. 2. Takagi K. The arthroscope. J Jpn Orthop Assn 14:359, 1939. 3. Watenabe M. Selfac-Arthroscope (Watenabe no. 24 Arthroscope) (monograph). Teishin Hospital, Tokyo, 1972. 4. Ferkel RD, Hommen JP. Arthroscopy of the ankle and foot. In: Surgery of the Foot and Ankle, ed 8, pp. 1641–1691, edited by MJ Coughlin, RA Mann, CL Saltzman, Mosby Elsevier, Philadelphia, 2007. 5. Guhl JF. Portals. In: Foot and Ankle Arthroscopy, ed 2, pp. 61–67, edited by JF Guhl, McGraw-Hill, New York, 1993. 6. Young BH, Flanigan RM, DiGiovanni BF. Complications of ankle arthroscopy utilizing a contemporary noninvasive distraction technique. J Bone Joint Surg Am 93:963–968, 2011. 7. Byrd JWT. Hip arthroscopy. J Am Acad Orthop Surg 14:433–444, 2006. 8. Beals TC, Junko JT, Amendola A, Nickisch F, Saltzman CL. Minimally invasive distraction technique for prone posterior ankle and subtalar arthroscopy. Foot Ankle Int 31:316–319, 2010. 9. Guhl JF, Patel D. Arthroscopic anatomy. In: Foot and Ankle Arthroscopy, ed 2, p. 28, edited by JF Guhl, McGraw-Hill, New York, 1993.
Contents lists available at ScienceDirect
The Journal of Foot & Ankle Surgery journal homepage: www.jfas.org
Tips, Quips, and Pearls “Tips, Quips, and Pearls” is a special section in The Journal of Foot & Ankle SurgeryÒ, which is devoted to the sharing of ideas to make the practice of foot and ankle surgery easier. We invite our readers to share ideas with us in the form of special tips regarding diagnostic or surgical procedures, new devices or modifications of devices for making a surgical procedure a little bit easier, or virtually any other “pearl” that the reader believes will assist the foot and ankle surgeon in providing better care. Please address your tips to: D. Scot Malay, DPM, MSCE, FACFAS, Editor, The Journal of Foot & Ankle SurgeryÒ, PO Box 590595, San Francisco, CA 94159-0595; E-mail: [email protected]
Fluoroscopic Method for Localization of the Anteromedial Portal for Use in Ankle Arthoscopy: Technique Tip Richard L. Needleman, MD Assistant Professor, Department of Orthopaedic Surgery, Wayne State University, Dearborn, MI
a r t i c l e i n f o
a b s t r a c t
Keywords: arthroscope C-arm fluoroscopy joint capsule surgery talus tibia
Ankle arthroscopy has become a standard surgical technique for the treatment of many ankle pathologies. Over the past 30 years, the technique has undergone modification and standardization in order to improve surgical performance and outcomes. In contrast to the ankle joint, the hip joint is a deep joint, which makes visualization and palpation of the topographical anatomy quite difficult. The use of fluoroscopy has enabled the surgeon to successfully perform hip arthroscopy for the treatment of selective hip pathologies. Fluoroscopy also can improve the localization of the anteromedial portal for use in ankle arthroscopy. This technique is valuable for the less-experienced ankle arthroscopist, in resident education, and for the experienced arthroscopist when surface anatomy palpation and visualization is less than ideal due to soft tissue edema and obesity. Ó 2013 by the American College of Foot and Ankle Surgeons. All rights reserved.
Arthroscopy was first performed in 1918 in a cadaver knee (1). Improvements in technology have allowed for the development of smaller arthroscopes, better light sources, and instrumentation. A standard method for the examination of the ankle was first published in 1939 by Takagi (2). Watenabe (3) published his experience with ankle arthroscopy with a fiberoptic arthroscope in 1972. Initially, visualization and surgery were confined to anterior compartment lesions. It was difficult to visualize and access posterior compartment lesions. In recent years, ankle arthroscopic techniques have continued to advance to allow for improved visualization and surgical access to the ankle. The surgical technique has become much more standardized in regard to the equipment, positioning, distraction, and portals used (4). The anteromedial ankle portal enters the ankle joint between the notch of Harty (at the junction of the anterior tibial lip and the medial malleolus) and the talar dome just medial to the anterior tibial tendon and 0.5 to 1 cm distal to the joint line. The notch allows for a small arthroscope to be more easily passed to the posterior compartment of the ankle than by way of the anterolateral portal (5).
Financial Disclosure: None reported. Conflict of Interest: None reported. Address correspondence to: Richard L. Needleman, MD, Assistant Professor, Department of Orthopaedic Surgery, Wayne State University, 18100 Oakwood Boulevard, Suite 300, Dearborn, MI 48124. E-mail address: [email protected]
The standard technique for establishing the anteromedial ankle portal has been well described (4). The surgeon must have a clear understanding of the surface anatomy. The initial placement of the anteromedial ankle portal is dependent on accurate palpation and visualization of the topographic anatomy of the ankle. The visualization and palpation of the key anatomic structures can be less than ideal owing to soft tissue edema and obesity. A less-experienced ankle arthroscopist might have more difficulty understanding the surface anatomy than an experienced ankle arthroscopist in less than ideal conditions. The surgeon will attempt to find the best angle to direct the arthroscope into the tibiotalar joint anteriorly from either the anteromedial or anterolateral portals to perform a complete ankle arthroscopic evaluation, including the posterior compartment. In some cases, it could be difficult owing to the presence of anterior spurs or “tight ankles.” It is important to distract the ankle with enough force to allow for adequate visualization and surgical access. Adherence to the standardized surgical technique has been advised for improved visualization, for better surgical access, and to avoid complications. Strong emphasis has been placed on proper portal placement, proper portal entry technique to minimize articular cartilage scuffing, and proper placement of the padded foot strap and noninvasive ankle distractor. Excessive soft tissue distraction using a padded foot strap has been thought to contribute to nerve hypersensitivity to the dorsal part of the midfoot (6).
1067-2516/$ - see front matter Ó 2013 by the American College of Foot and Ankle Surgeons. All rights reserved. http://dx.doi.org/10.1053/j.jfas.2012.10.001
258
R.L. Needleman / The Journal of Foot & Ankle Surgery 52 (2013) 257–259
Fig. 1. Fluoroscopic set up.
As with any surgical procedure, evolutionary development toward a better technique is ongoing. Arthroscopy has been the benefactor of technological advances. The knee was the first joint to undergo arthroscopic evaluation because of its large size and location close to the skin. The surface anatomy was easy to palpate and understand. Other joints have followed, including smaller joints close to the skin (ankle and wrist) and joints deep to the skin (hip). Initially, arthroscopists had difficulty with the hip (a large joint deep to the skin) because of the difficulty in palpating key anatomic landmarks. A more successful approach to hip arthroscopy using C-arm fluoroscopy for proper portal placement and portal entry has improved visualization of the hip and reduced the risk of complications (7). Beals et al (8) described a technique for posterior ankle and hindfoot arthroscopy with the patient lying prone. The proper portal position is dependent on the location of the procedure to be performed. For example, a lower portal will facilitate posterior ankle arthroscopy. Mini–C-arm fluoroscopy has routinely been used to guide portal placement (8). The addition of mini–C-arm fluoroscopy to the standard supine ankle arthroscopy technique to obtain real-time intraoperative lateral images of the ankle joint during initial anteromedial portal placement can facilitate proper location of the anteromedial portal. This allows for the safe entrance of the arthroscope into the ankle using the optimal “entrance angle” with the least amount of noninvasive distraction to perform adequate visualization of both the anterior and the posterior compartments and reduce the risk of complications.
Fig. 2. Intraoperative fluoroscopic images showing localization of anteromedial portal. (A) Needle introduced into ankle joint by way of anteromedial portal. (B) Optimal “entrance angle” (q) determined to allow for easier passage of arthroscope to posterior compartment. Optimal “entrance angle” is angle between longitudinal axis of tibia (line) and axis of arthroscope (arrow). (C) Blunt 2.7-mm trocar placed into ankle joint along proper entrance angle. (D) The noninvasive distractor might need to be adjusted. Next, a blunt trocar is placed within a 2.9mm arthroscopic cannula into ankle joint along proper entrance angle.
R.L. Needleman / The Journal of Foot & Ankle Surgery 52 (2013) 257–259
Operative Technique Before inserting the arthroscope in the anteromedial portal, the joint should be carefully distracted with a soft tissue distraction strap and the external anatomic landmarks marked (saphenous vein and anterior tibial tendon). The initial placement of the anteromedial ankle portal depends on the accurate palpation and visualization of the topographic anatomy of the ankle. The key structures for palpation include the anterior tibial tendon (which is almost always palpable) and the anterior tibiotalar joint line (between the talar dome and the anterior tibial lip) medial to the anterior tibial tendon. The joint line is identified by palpation with dorsiflexion and plantarflexion of the ankle. The mini–C-arm is set up to obtain real-time intraoperative lateral images of the ankle joint (Fig. 1). The exact placement of this portal is located with a hypodermic or spinal needle just medial to the anterior tibial tendon and just distal to the tibiotalar joint line by about 0.5 to 1 cm. Next, one should introduce a needle into the ankle joint by way of the anteromedial portal with fluoroscopic assistance (Fig. 2A). The ankle joint is then distended with saline or lactated Ringer’s solution to facilitate placement of the arthroscope and minimize scuffing of the articular cartilage. The portal is placed using a “nick and spread” technique. The ”entrance angle” is determined to allow for safe passage of the arthroscope to the posterior compartment without any damage to the tendon or bone or scuffing of the articular joint cartilage. This angle is defined as the angle between the arthroscope (or instruments) and the longitudinal axis of the tibia (Fig. 2B). A blunt 2.7-mm trocar is placed into the ankle joint along the proper “entrance angle” (Fig. 2C) to dilate the portal. The noninvasive distractor is adjusted to allow for the least distraction force to perform this maneuver. The trocar is then removed and replaced with a blunt trocar within a 2.9-mm arthroscopic cannula into the ankle joint along the proper “entrance angle” (Fig. 2D). The noninvasive distractor is adjusted. The trocar is then removed, leaving the cannula in place. Finally, the arthroscope is inserted into the ankle by way of the cannula. Discussion Fluoroscopy has undergone many technical improvements, including portability and smaller machines. Fluoroscopic machines are frequently used by foot and ankle surgeons in the operating room during hip fracture surgery and intramedullary fixation of the long bones. With the advent of smaller portable units, hand and foot surgery has benefited, with better patient outcomes. With the development of arthroscopic techniques of the hip, fluoroscopy has been a critical factor because it allows the arthroscopist to access the hip joint with proper portal placement and portal entry. Adherence to the standardized surgical technique has been advised for improved visualization of the hip, better surgical access, and to avoid complications (7). With the use of fluoroscopy to assist with portal placement and portal entry during ankle arthroscopy, similar surgical success should be achieved. A small-diameter arthroscope can pass further into the ankle, with improved visualization of most of the articular surfaces of the talus and tibial plafond than with an arthroscope with a larger diameter (9). The “entrance angle” should conform to the natural curve of the talus and the matching curve of the tibial plafond. The presence of anterior spurs can contribute to a deepening of the concavity of the tibial plafond and
259
would therefore require more distraction to further separate the talus from the tibia. Excessive soft tissue distraction using a padded foot strap has been thought to contribute to nerve hypersensitivity to the dorsal part of the midfoot (6). To reduce the risk of this complication, it is advisable to use the least amount of noninvasive distraction necessary to allow for entrance of the arthroscope into the ankle to perform adequate visualization of the ankle, anteriorly and posteriorly. Intraoperative fluoroscopy can help the surgeon safely insert the arthroscope to visualize the posterior compartment without excessive distraction, lessening the forces on the dorsum of the foot. The proper placement of the anteromedial ankle portal under fluoroscopy can reduce complications by minimizing scuffing of the articular cartilage and achieving sufficient distraction to perform ankle arthroscopy while avoiding excessive distraction, minimizing the risk of possible cutaneous nerve injury. The optimization of the “entrance angle” improves visualization of the posterior ankle joint through verification of the passage of the cannula into the posterior compartment of the ankle. This technical modification will make ankle arthroscopy easier for less-experienced surgeons to perform with fewer complications and make it easier to instruct residents. Patients with poor external landmarks because of obesity and/or edematous ankles would qualify for minimal incision ankle arthroscopy instead of ankle arthrotomy, with the added benefits of better joint visualization and improved surgical technique. Ankle arthroscopy can also be attempted and successfully performed in those patients with large anterior ankle spurs, instead of ankle arthrotomy. Surgeons frequently perform supine ankle arthroscopy using the anteromedial and anterolateral portals. These portals are the basic portals for ankle arthroscopy. The posterolateral portal has been recommended as a portal dedicated to outflow or for visualization of a posteromedial talar lesion, anterior osteophyte, or loose body, with the anterior portals becoming the working portal and outflow portal. Although this portal is frequently cited in the standard surgery technique, most ankle arthroscopists have not embraced it, because it is more difficult to achieve proper portal placement and proper portal entry than the anterior portals. The anterior aspect of the ankle is closer to the skin, and the posterior aspect of the ankle is deeper to the skin. The surface anatomy of the posterior ankle is more difficult to delineate. Future studies will use the mini–C-arm to aid with proper posterolateral portal placement and proper portal entry technique for supine ankle arthroscopy. References 1. O’Connor RL. Arthroscopy, Upjohn, Kalamazoo, MI, 1977. pp 12–16. 2. Takagi K. The arthroscope. J Jpn Orthop Assn 14:359, 1939. 3. Watenabe M. Selfac-Arthroscope (Watenabe no. 24 Arthroscope) (monograph). Teishin Hospital, Tokyo, 1972. 4. Ferkel RD, Hommen JP. Arthroscopy of the ankle and foot. In: Surgery of the Foot and Ankle, ed 8, pp. 1641–1691, edited by MJ Coughlin, RA Mann, CL Saltzman, Mosby Elsevier, Philadelphia, 2007. 5. Guhl JF. Portals. In: Foot and Ankle Arthroscopy, ed 2, pp. 61–67, edited by JF Guhl, McGraw-Hill, New York, 1993. 6. Young BH, Flanigan RM, DiGiovanni BF. Complications of ankle arthroscopy utilizing a contemporary noninvasive distraction technique. J Bone Joint Surg Am 93:963–968, 2011. 7. Byrd JWT. Hip arthroscopy. J Am Acad Orthop Surg 14:433–444, 2006. 8. Beals TC, Junko JT, Amendola A, Nickisch F, Saltzman CL. Minimally invasive distraction technique for prone posterior ankle and subtalar arthroscopy. Foot Ankle Int 31:316–319, 2010. 9. Guhl JF, Patel D. Arthroscopic anatomy. In: Foot and Ankle Arthroscopy, ed 2, p. 28, edited by JF Guhl, McGraw-Hill, New York, 1993.