Over the last few decades, arthroscopy has become an advanced treatment method offering enhanced visualization of the joint, accuracy and low complication rates. These authors offer insights on arthroscopy portal location, helpful surgical pearls from their experience and tips on post-op care.
Arthroscopy is a valuable tool in the management of a variety of intra-articular pathologies. Ankle arthroscopy in particular allows unrivaled diagnostic visualization of the ankle joint with the opportunity to treat ankle joint pathology at the same time. It also offers the additional benefit of having relatively low morbidity and high rates of patient satisfaction when a well-trained surgeon conducts the surgery.
Takagi first described arthroscopy in the Japanese medical literature in 1918.1 The original scope model was based upon pediatric cystoscopies of the time. Takagi later described the first ankle arthroscopy technique in the Japanese orthopedic literature in 1939.1 By 1949, smaller scopes with magnifying optics had emerged but it was not until the 1970s that arthroscopy became popular in North America. This popularity was aided by the advent of power shavers, abraders and retrograde knives. In 1980, Johnson published the first ankle arthroscopy paper in America.2 Finally, the first ankle arthroscopy courses (pioneered by Lundeen and Gurvis) were offered to podiatric surgeons in 1984.3
Since 1984, ankle arthroscopy has become a widespread and versatile technique that many podiatric surgeons use to treat ankle pathology in their practices. Its popularity has grown because surgeons can perform the procedures quickly with increased accuracy and lower complication rates. Arthroscopy also offers shorter recovery times in comparison to other operative techniques for treating intra-articular pathology.
What You Should Know About Indications And Complications
So when is ankle arthroscopy indicated? As with any pathology that we encounter in podiatric practice, one should exhaust all conservative treatment before considering surgical intervention. Conservative care options include immobilization, nonsteroidal anti-inflammatory drugs (NSAIDs), physical therapy, tapered dosing of prednisone and intra-articular corticosteroid injections.
Diagnostic indications for ankle arthroscopy include unexplained pain, stiffness, instability, hemarthrosis, edema, locking of the joint, lateral ligamentous laxity, aching within the joint, joint line tenderness and popping with range of motion.
Traditional imaging modalities have their limitations. Radiographs cannot show the cartilage itself, allowing for one to miss osteochondral defects. Radiographs also tend to have a lag effect in diagnosis, especially for subtle new injuries. This can happen with stress fractures. Computed tomography (CT) can allow for assessment of the size of a lesion. Magnetic resonance imaging (MRI) can give the surgeon insight on the extent of the injury and if osteonecrosis is present. Inserting a camera into the joint can allow the surgeon to directly visualize pathologies that other imaging modalities may miss.
After establishing a diagnosis either by arthroscopic visualization or other methods, one may use arthroscopy to effectively treat a variety of pathologies. Indications for arthroscopic treatment include: debridement of synovitis, soft tissue impingement, arthrofibrosis, loose bodies, accurate anatomical fracture reduction, osteophytes, osteochondral defects, articular cartilage injury, debridement of gouty tophi and debridement of cartilage for joint preparation in ankle arthrodesis procedures.
Even though ankle arthroscopy has a low morbidity and is a relatively safe surgical procedure, contraindications to this treatment modality still exist. Moderate to severe degenerative joint disease, decreased range of motion and a markedly reduced joint space will not allow surgeon to use or maneuver the instrumentation adequately in the joint space. Severe edema and questionable vascular status can cause wound healing complications, even with the small size of the incisions surgeons would use for ankle arthroscopy.
Finally, soft tissue infection in the soft tissues overlying the operative ankle is an absolute contraindication to prevent inoculation of the ankle joint with bacteria, leading to a septic ankle joint.
Possible complications of this procedure include: further damage to the articular surface, neuropraxia, neuritis, vessel injury, synovial fistula formation, hemarthrosis leading to joint fibrosis, subchondral plate collapse, osteoarthritis and deep vein thrombosis. It should be stated that as with most foot and ankle surgical procedures, the occurrence of deep vein thrombosis from ankle arthroscopy is very low and prophylaxis is rarely necessary unless the patient’s individual history warrants such action.
A Guide To Arthroscopy Portal Location
Cartilaginous tissue lacks nerve or blood supply, which lends itself to poor healing following injury. The cartilage within the ankle joint is typically 2 to 3 cm thick. Articular cartilage is composed of three layers: the superficial, tangential and vertical layers. The vertical layer is the thickest stratum of the three. The smooth joint contour cartilage is attached to the subchondral bone via a lock and key mechanism. It is this subchondral bone, specifically the zone of calcified cartilage, which provides some of the nourishment to the chondrocytes via its blood supply. The remainder of the nourishment for the cartilage derives from the synovial fluid.
One can access the ankle joint from the anterior or posterior aspect of the joint. There are three chief incision locations or portals that are in use most often in ankle arthroscopy. Surgeons can strategically place these portals to gain access to the ankle joint with instrumentation while minimizing the risk of damage to anatomical structures
around the ankle, especially nerves and blood vessels.
Locate the anteromedial portal by palpating the tibialis anterior tendon and make an incision just medial to this structure at the level of the joint line. This location ensures that the anterior tibial artery and the deep peroneal nerve will be safe from trauma during the procedure. This is the safest portal anatomically speaking.
The anterolateral portal is another commonly used point to access the ankle joint. Make this portal at the level of the ankle joint line and just lateral to the peroneus tertius tendon. The dorsal cutaneous nerves are at risk of injury when one selects this portal. Surgeons can minimize injury to these structures by plantarflexing and inverting the foot. Inserting the camera in the anteromedial portal and using its light source to transilluminate the anterolateral portion of the ankle can often aid in visualizing the ankle.
The third most regularly used portal in ankle arthroscopy is the posterolateral portal. This portal is located just lateral to the Achilles tendon overlying the joint line. The joint line is much more difficult to palpate when using this technique. The sural nerve should pass safely anterior to this portal.
There are three less commonly used portals that authors have described in the arthroscopic literature. The anatomical sites of these less commonly used portals have an increased risk of damaging nerves or blood vessels. Surgeons should only use these portals if they are unable to access the pathology within the joint from the three principal and safest portals I described previously.
The central anterior portal is located just lateral to the extensor hallucis longus tendon at the level of the tibiotalar joint. The anterior tibial vessels and deep peroneal nerve are at high risk for injury with this approach.
The posteromedial approach is located just medial to the Achilles tendon at the level of the joint line. This portal puts the posterior tibial vessels, tibial nerve, medial calcaneal nerve and flexor hallucis longus tendon at risk with this technique.
The final portal described in ankle arthroscopy is a transmalleolar approach through the lateral malleolus. Guhl described the lateral malleolar portal in 1988 for accessing osteochondral defects on the posterior aspect of the talus.4
Ensuring Appropriate Instrument Selection
After performing incisions and blunt dissection to the level of the capsule, the surgeon can use a trocar or an obturator to pierce the joint capsule and employ a cannula to maintain the portals after their establishment. Trocars are solid rods with a sharp pyramidal tip while an obturator is a solid rod with a blunt tip. The obturator is a much safer instrument for establishing a portal and surgeons should use this whenever possible to decrease the chance of damaging healthy cartilage when establishing the portals.
There is a wide array of instrumentation for arthroscopy. Paramount on this list is the arthroscope with a camera and light source to allow the surgeon to visualize the intra-articular space on a monitor. The camera comes in three different lens angles, which one can orient 0, 30 or 45 degrees from the shaft of the arthroscope. The angled lenses allow the surgeon to view the tibial or talar cartilage without the need to angulate the arthroscope and possibly score healthy cartilage with the camera.
Insert the camera into the joint through a cannula, which helps to maintain the portal during the procedure. The ingress and egress of fluid through the instrumentation aid in distending the joint space and synovium to maximize visibility within the joint. One can use lactated Ringer’s solution as it is the most physiologic fluid readily available.
Once the pathology is visible, there are a variety of instruments you can use to treat the patient. These include shavers, abraders, cutters, specialized instrumentation for grasping loose bodies, curettes and lasers. All of the equipment for ankle arthroscopy is available in different diameters with 2.7 mm and 4.0 mm instruments being the most commonly used sizes for the ankle joint.
A Brief Overview Of Four Terms For Instrument Manipulation
Ankle arthroscopy has four main terms that describe how surgeons manipulate the instrumentation within the joint.
• Scanning is the use of the camera to inspect the entire joint line visually. It allows the surgeon to locate the pathology and assess for further injuries that he or she may not have previously identified.
• Triangulation involves orienting the camera lens and an instrument within the ankle joint at the point of pathology at the same time. This principle allows the surgeon to inspect the pathology while the instrument manipulates it and visualize the location as the treatment occurs.
• Pistoning is the advancement and withdrawal of the camera within the joint space as the camera scans the joint. Pistoning allows the inspection of the talar neck, synovium and ankle gutters and recesses.
• The final basic principle of arthroscopy is rotation. Rotation enables one to visualize the areas around the lens in all directions without pistoning the camera.
Key Treatment Considerations With Ankle Arthroscopy
Now that we have discussed the background, terminology and instrumentation, how can we use them to treat patients?
For example, chondroplasty is the debridement of fibrillated or uneven cartilage that hinders the normal motion of the joint. One can perform this technique with a power shaver, abrader or a curette. It is important to be gentle. Surgeons should smooth the joint surface and take care not to create osteochondral defects. Chondroplasty is generally not the initial choice of treatment for cartilage pathologies because it does not revascularize the defects themselves but simply restores normal contour to the cartilage.
Abrasion arthroplasty is another useful technique in ankle arthroscopy. This method involves resecting islands of necrotic cartilage and subchondral bone down to the tidemark. The tidemark is the anatomical level in the subchondral bone lying between the calcified and non-calcified cartilage. The tidemark is typically about 1 mm into the subchondral bone. This level is important because it is vascularized, which will facilitate healing of the defect with fibrocartilage. Since the tidemark or zone of calcified cartilage is only 1 mm down, it is once again important to be gentle with the debridement of the cartilaginous lesions. Overzealous debridement of the subchondral bone can predispose the joint to arthritic changes. One can easily perform abrasion arthroplasty with a small burr.
Arthroscopy of the ankle generally occurs in the outpatient setting with the patient under general, regional or spinal anesthesia. The patient should be in the supine position unless the surgeon opts to use the posterior portals to access pathologies that the typical anterior portals cannot reach. In these cases, a prone position may be warranted with the proper offloading of bony prominences. The patient’s knee can either be extended or the hip and knee can be flexed. Positioning is based upon surgeon preference.
Distraction of the ankle joint can offer easier maneuverability of the instrumentation within the joint space. Distraction can be either invasive with pins above and below the joint line, or noninvasive with a harness. However, De Leeuw and colleagues showed that the distracted ankle places the neurovascular structures about the ankle joint at a higher risk of iatrogenic injury when the bulk of the procedure focuses on the anterior portion of the joint.5 Ankle joint dorsiflexion can be a substitute for distraction in these cases, such as debridement of a bony exostosis on the anterior tibia.
The tourniquet should be at the level of the thigh. Before portal dissection and inserting instruments into the joint, inflate the space with 15 to 20 mL of lactated Ringer’s solution or saline through the same location as the anteromedial portal with an 18-gauge needle. The injected fluid will help to distend the joint space and the synovium for better visibility, and maximize the space in which the surgeon can work.
Pertinent Pointers On Post-Op Care
Postoperative management focuses on early range of motion. Two to five days following ankle arthroscopy, the patient can remove the posterior splint and begin passive range of motion exercises. This early range of motion will help the new fibrocartilage to better contour to the joint as it is deposited and will prevent stiffness of the joint.
The patient should then wear a partial weightbearing cast for four to six weeks to allow the cartilage to repair and fill in with fibrocartilage. After six weeks, the patient should begin physical therapy to regain range of motion. Patients should postpone all impact activities for 12 weeks. Typically, NSAIDs provide satisfactory analgesia following ankle arthroscopy. It is also important to inform the patient that for many months after the procedure, considerable edema may be present at the level of the ankle where arthroscopy occured.
Ankle arthroscopy continues to be a safe procedure to treat a wide array of ankle joint pathologies. As technologies continue to advance, we will likely see more and more indications for this procedure. The longer a podiatric surgeon can postpone the onset of osteoarthritic changes to the ankle joint, the more active and happy his or her patients will be.
Dr. DeHeer is a Fellow of the American College of Foot and Ankle Surgeons, and a Diplomate of the American Board of Podiatric Surgery. He is also a team podiatrist for the Indiana Pacers and the Indiana Fever. Dr. DeHeer is in private practice with various offices in Indianapolis.
Dr. Groh is a first-year podiatric resident at Community Westview Hospital in Indianapolis.
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12. Sitler DF, Amendola A, Bailey CS, et al. Posterior ankle arthroscopy: an anatomic study. J Bone Joint Surg. 2002; 84-A(5):763-769.
13. Mayer DP, Kabbani YM. Special imaging procedures, MRI/cross-sectional imaging: osteochondral fractures. In: Christman RA (ed): Foot and Ankle Radiology. Chapter 17, Churchill Livingstone, St. Louis, 2003.
14. Miller MD, Hart J. Basic arthroscopic principles. In: DeLee JC, Drez D Jr, Miller MD (eds): DeLee and Drez’s Orthopedic Sports Medicine, third edition, chapter 2, section A, Saunders, Philadelphia, 2009.
15. Oloff LM, Ardizzone R, Greenan D. Ankle arthroscopy: osteochondral defects. In: Chang TJ (ed): Master Techniques in Podiatric Surgery: The Foot and Ankle, chapter 39. Lippincott Williams & Wilkins, Philadelphia. 2005.
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For further reading, see “Current Concepts In Ankle Arthroscopy” in the December 2007 issue of Podiatry Today, “A Pertinent Guide To Basic Ankle Arthroscopy” in the November 2003 issue or “A Closer Look At Arthroscopy For Ankle Fractures And Post-Fracture Defects” in the September 2009 issue. To access the archives, visit www.podiatrytoday.com .
Dr. DeHeer pens a monthly blog for Podiatry Today. To read his blogs, visit http://tinyurl.com/c3jnzss .