Ankle Fusion/Arthrodesis

What is an ankle arthrodesis?

The ankle joint consists of portions of three bones: the talar dome, distal tibial plafond and distal fibula. The talus and tibia portions make up over 80% of the articular surface area of the ankle joint. Arthrodesis procedures are the removal of cartilage and any diseased bone from a joint to produce a fusion of at least two bones to create one bone. This removal of cartilage exposes the underlying bone on both sides of the joint. These joints surfaces are then compressed together with some form of fixation to create the fusion. In an ankle arthrodesis, typically the tibial position is fused to the talus. In some cases the fibula is part of arthrodesis, but this is the surgeon’s preference.

Why is an ankle arthrodesis procedure performed?

Ankle arthrodesis procedures are typically performed when all conservative options have been attempted and failed. Some of these treatment options, are corticosteroid injections, ankle foot orthoses, anti-inflammatory medications, custom orthotics, ankle braces, and sometimes arthrotomy or arthroscopy. In cases where the pain and/or the deformity is unremitting the arthrodesis is recommended. Some of the conditions that produce unremitting pain and deformity in the ankle joint are:

1. Post-traumatic arthritis
2. Rheumatoid arthritis
3. Infection
4. Failed ankle implant
5. Congenital ankle deformities
6. Neuromuscular disorders (i.e. post-polio syndrome, paraplegia, etc.)
7. Lateral ankle instability (after failure of operative and non-operative treatment)
8. Avascular Necrosis (secondary to trauma or metabolic disease states)
9. Charcot Neuropathy

Techniques for ankle arthrodesis

Over the years many techniques have been devised to fuse the ankle joint. Today there are three different techniques that your surgeon may use. They are open technique (use of one or two incisions on the outside and the front of your ankle) with screw fixation, open technique with external fixator fixation and arthroscopic ankle arthrodesis. Most surgeons use all three of these techniques, with the open technique with screw fixation the most commonly used. The technique used is surgeon's preference for your clinical findings, but all have equal fusion rates. Sometimes your doctor may need the use of bone graft, typically taken from your hip area (iliac crest), if you have defects in you ankle from previous trauma or surgery to help support the arthrodesis site.

What to Expect Following the Procedure

After most ankle arthrodesis procedures, your surgeon will have you non-weightbearing (no weight on your foot) typically for a period of 6-12 weeks, but this can be extended longer if there is any delay in healing of the arthrodesis site. After the surgery, you will be in a below knee cast or splint to help protect the surgical site and also prevent any movement. After the 6-12 weeks period your surgeon, will typically start you partially weightbearing with your crutches with the use of some type of cast or ankle brace for 4-6 weeks. Once you are fully weightbearing in the cast brace, you will be progressed into high-topped shoe or sneaker. Sometimes modifications have to be made to your shoes, called a rocker-bottomed sole, to aid in push off in ambulation after surgery.

Some other things that are important to note after the surgery, typically there will be some level of pain or discomfort after the surgery. In a majority of cases, you will be admitted after the surgery to the hospital for pain management. This admission can range from 23 hour to 3-4 days based on an individual’s pain tolerance. When in the hospital and also when you go home it is essential that you keep your foot elevated and use ice as recommended by your surgeon. Ice and elevation will help to reduce the swelling around your foot and ankle that is common after a major surgical reconstruction. The swelling in your foot and ankle can last for 6-9 months and even up to a year. Another thing that is tied closely to the swelling after surgery is a phenomenon that occurs when you get up from after you have had your foot elevated for a period of time. What happens is when you dangle your leg to get up, blood flow will increase into the foot and ankle which will create a throbbing sensation and sometimes a pins and needles sensation in your foot. This is perfectly normal and will go away when you re-elevate your foot.

Recovery Time

Time off work depends on the type of ones work as well as the procedures performed. Usually a patient can return to work in 2 to 4 weeks if they are able to work while seated. If a persons job requires standing and walking, return to work may take several weeks when one is able to bear weight. Complete recovery may take six months to a full year.

Potential Complications

Complications can occur as with all surgeries, but are minimized by strictly following your surgeons post-operative instructions. The main complications include infection, bone that is slow to heal or does not heal, progression or reoccurrence of deformity, a stiff foot, and the need for further surgery. Many of the above complications can be avoided by only putting weight on the operative foot when allowed by your surgeon.

Arthroscopy of the Ankle and Subtalar Joints

Arthroscopy is a surgical technique that involves the introduction of a small circular lens (2.0 to 6.0 mm in diameter) into a joint for the purpose of inspection and possible treatment. The arthroscope is an elongated tube possessing a series of lenses that allow for the magnification of structures within the joint. A camera is affixed to end of the arthroscope so that joint images can be projected onto a television monitor. Small incisions (one-quarter inch or less) are placed strategically around the joint to allow for the introduction of the arthroscope, as well as other pieces of equipment needed for the precise correction of joint injury.

Arthoscopy vs. Arthrotomy (Open Technique)

Arthroscopy offers several advantages over classical "open joint" (arthrotomy) techniques. First, arthroscopic evaluation and treatment only requires small incisions in the joint capsule, limiting the degree of scarring and trauma associated with surgery. Second, the environment within the joint is more easily inspected by virtue of the magnification provided by the arthroscope. Third, removal of damaged joint tissue or scarring is achieved in a more precise manner as a consequence of the very fine, specially designed equipment. Fourth, the joint is continuously bathed in physiological fluids providing a healthier environment during surgery. This is in contrast to open joint techniques where the cartilage surface is exposed to air within the operating room, potentially compromising its viability. Unfortunately, situations do arise when the joint needs to be opened in order to achieve the objectives of the surgical procedure. For example, certain cartilage injuries within the ankle joint may be located in areas where arthroscopic visualization is poor, or access to the lesion with available equipment is nearly impossible. In these cases, even though an arthrotomy was necessary due to inaccessibility, the arthroscope is invaluable in specifically identifying the location, and extent of the problem.

Ankle and Subtalar Anatomy

The ankle joint is comprised of three bones, the tibia (inner ankle and leg bone), the fibula (outer ankle and leg bone), and the talus (odd shaped, lower ankle bone). The ankle joint space is found between the talus and the tibia, as well as between the talus and the fibula. A large majority of the articular surface of the talus is in contact with the cartilage surface of the tibia. These two surfaces are slightly dome shaped from front to back. The ankle joint allows the foot to mobilize up (dorsiflexion) and down (plantarflexion). There are three major ligaments associated with the outer part of the ankle joint: the Anterior Talofibular, Calcaneofibular, and Posterior Talofibular ligaments. There is one major ligament with several bands associated with the inner part of the joint: the Deltoid ligament. Together these ligaments guide motion and provide stability to the ankle joint.

The lower ankle joint or subtalar joint (below the talus) exists between the talus and the heel bone (calcaneus). The subtalar joint is actually made up of two anatomically distinct joints. These two joints are separated by a void or space, which houses the two major ligamentous stabilizers of the subtalar joint: the Interosseous Talocalcaneal and Cervical Ligaments. Further stability is afforded to the subtalar joint by one of the three lateral ankle ligaments (Calcaneofibular Ligament), and several bands of the main inner or medial ankle ligament (Deltoid Ligament). The subtalar joint allows the foot to pronate and supinate. Supination of the subtalar joint involves movement of the foot in an inward direction, so that the sole of the foot faces the opposite limb. Pronation of the subtalar joint involves movement of the foot in an outward direction, allowing the sole to face away from the opposite limb.

Rearfoot and Ankle Inversion Injuries: Mechanism of Injury

During a common ankle sprain, the foot is forcibly rotated inward toward the opposite leg. The inward movement of the foot is a motion well accommodated by the lower ankle joint (subtalar joint), but not by the upper or true ankle joint. Ultimately, the lower ankle joint comes to the end of its available inward motion, and stops rather abruptly (the lower ankle joint can be injured at this point). Continued inward movement of the foot forces the ankle joint in a direction it is not designed to accommodate. The lower ankle bone or talus is thus forcibly directed inward, partially dislocating the talus out from under the tibia and fibula. It is not uncommon for the outer ankle ligaments to be partially or completely torn, resulting in joint instability. Furthermore, the adjacent joint surfaces can collide or impinge during the injury, resulting in disruption of the cartilage surface.

Arthroscopy: Indications for usage

Arthroscopy is an effective tool for the evaluation and management of pain localized to the ankle or lower ankle (subtalar) joints. Following an ankle sprain, ligamentous scarring can occur within various regions of the ankle or subtalar joints. Arthroscopy allows direct visualization and precise removal of scar tissue with minimal joint trauma. Generally, two to four portals or incisions are required for ankle arthroscopy, and two or three for subtalar arthroscopy. Loose fragments of bone, cartilage or ligament can be identified and removed through the small portals in the joint capsule. Occasionally, small accessory incisions may be necessary to remove larger fragments of tissue found within the joint. Regions of the joint surface that have been injured will commonly display an obvious defect or a loose flap of cartilage that has been delaminated from the underlying bone. Not infrequently, the joint surface will appear normal; however, gentle probing will reveal an area of softness compared to surrounding cartilage. These soft areas are regions of cartilage injury and will require removal of the damaged cartilage. In some cases, physicians are drilling small holes through these soft zones in order to promote re-adhesion of the cartilage. In areas where there is an obvious defect in the cartilage surface, the damaged cartilage is removed down to normal cartilage. Following the removal of damaged cartilage, the exposed underlying bone is drilled repetitively to facilitate bleeding into the base of the injured area. The blood will form a clot across the full dimensions of the defect. Over time the blood clot is converted to cartilage. The repair cartilage is not of the same quality as was originally present; however, the repair cartilage re-establishes near normal surface-to-surface contact. In some cases, small plugs of normal cartilage and bone can be removed from one location within the ankle joint, and placed into an area of cartilage injury. Unfortunately, transport of cartilage within the ankle joint necessitates an open joint technique and cannot be performed arthroscopically.

Arthroscopy has also been useful in assisting with the repair of fractures that involve the surfaces of the ankle joint (Pilon fractures or talar fractures). In these cases, the arthroscope is used to visualize the fractured joint surface as it is repaired to assure accurate realignment. Arthroscopy has also been used to visualize the joint during removal of the articular cartilage prior to fusion of the ankle joint.

Conditions Where Arthroscopy may not be Useful

Unfortunately, arthroscopy is not helpful in certain types of joint injury. If a cartilage lesion is located in the central or back portion of the joint, many times the lesion cannot be accessed with the arthroscope. In these cases, the tibia or inner ankle bone must be cut in order to allow inspection and treatment of the lesion. Ankle fusions cannot be performed arthroscopically if a large degree of malalignment exists within the ankle joint itself. In these cases, the joint must be opened and the joint surface remodeled to reduce the deformity. Although some surgeons are repairing single ligament tears through the arthroscope, this has not gained universal acceptance. Significant joint instability associated with multi-ligament injury requires open joint repair or reconstruction techniques.

Arthroscopic Surgery of the Ankle and Subtalar Joints

Arthroscopic surgery of either the ankle or subtalar joints is generally considered an outpatient (same day) surgical procedure. Pre-operatively or intra-operatively, patients are usually given antibiotics to reduce the risk of infection. The surgery can be performed under either general or spinal anesthesia. Arthroscopy can also be performed under local anesthesia with IV sedation. The latter procedure requires the anesthesiologist to use a local anesthetic to block the large nerve behind the knee joint (main nerve block). The surgeon will further supplement the main block with local anesthetic infiltrated just above the ankle joint. The patient is then kept in a twilight sleep with medications infiltrated through the IV by the anesthesiologist. Post-operatively, the ankle is lightly bandaged. The patient may be placed in a removable cast boot or splint to keep the ankle at 90 degrees to the leg; however, gentle range of motion is recommended on a regular basis after surgery. Following surgery, patients are usually non-weight bearing for 7-14 days, and then are allowed to weight bear as tolerated. If a large cartilage lesion was either drilled or cleaned out, patients will remain non-weight bearing up to 4 weeks. The actual duration of non-weight bearing will depend on the extent of the injury and the type of treatment rendered. It is not uncommon for patients to undergo physical therapy after surgery, especially if they had a prolonged period of pain and disuse prior to surgery.

Risks and Complications Associated with Ankle or Subtalar Arthroscopy

Like any other surgical procedure, arthroscopy has certain inherent risks and complications. In the author's experience, these have been uncommon. The literature sites injuries to the superficial nerves as the most common complication after ankle arthroscopy. Most of these nerve related injuries result in tingling, numbness, or occasionally burning sensations across the outer part of the ankle onto the top of the foot. Most of these sensations resolve over a period of 3-5 months. Obviously, more significant nerve related injuries have been reported, but they are uncommon. There is the risk of infection; this complication is rarely seen with appropriate antibiotic prophylaxis prior to surgery and sterile technique during surgery

Conclusions

Arthroscopy of the ankle or subtalar joints has proven to be a valuable tool for treating various injuries to these unique joints. The degree of joint and soft tissue trauma associated with arthroscopy is no doubt less than open joint techniques, resulting in somewhat faster healing times. Immediate return to walking and sports is not usually recommended. The joint can be often sore and swollen for several weeks after surgery. Aggressive and rapid return to activity can result in a more prolonged recovery time. Listen to physician instructions and follow carefully.

Surgery of Hindfoot and Ankle Deformities

Hindfoot and ankle deformity may result in decreased activity levels, inability to maintain meaningful employment, inability to walk or difficulty getting through activities of daily living. These severe deformities are often the result of previous trauma, congenital birth defects, acquired from degenerative changes throughout the course of one's adult life or may be secondary to systemic disease. Diseases such as diabetes mellitus, rheumatoid arthritis and various types of neuromuscular conditions may result in severe foot and ankle deformity. The deformities ultimately result in pain and difficulty walking.

Non-operative therapy including orthotics, injection therapy, anti-inflammatory medications, bracing, etc. are the first lines of treatment to provide comfort and maintain activities of daily living. However, certain deformities may fail to respond to non-operative care. Surgery can eliminate the deformity, decrease pain and increase activity level. Surgery is the ultimate solution to restore a relatively normal functioning foot that will permit a person to get through activities of daily living or maintaining meaningful employment.

Surgical Intervention

Surgery often consists of arthrodesis (fusion) procedures that permit a realignment of the existing deformity. The ultimate goal is to reconstruct the bony architecture of the foot so that the foot may be placed into appropriate footgear or bracing so that a patient can walk without pain. The exact surgery depends on the specific nature of the deformity. Realignment arthrodesis sometimes requires a 1-2 night stay in the hospital but is usually performed as an out-patient. These procedures are preformed under general inhalation anesthesia. Various types of internal and external fixation devices are often required either temporarily or permanently to maintain the foot or ankle in the appropriate alignment during the healing process.

Recovery Time

The postoperative convalescence includes three months in a non-weight-bearing short leg cast. This is followed by protected weight-bearing in a rocker bottom brace for an additional 2-3 months. The patient is then ultimately placed in custom molded or extra depth shoe with an appropriate orthotic or a permanent brace.

Possible Complications

Complications include infection, nonunion (failure of bones to heal together), fixation problems and malalignment (failure of realignment to be maintained). Additionally, stress fractures of the tibia (long leg bone) have been reported. These complications are managed by early recognition and prompt intervention. These complex procedures often require revisonal surgery to address complications.

Summary

Realignment arthrodesis of the hindfoot and ankle can be a very gratifying procedure. The ultimate goal is to have a patient who can walk without pain. Although surgery does provide realignment, some type of support in the form of an orthotic or brace is often required. The postoperative convalescence is quite extensive and the patient and their families should have a thorough consultation by the surgeon. It may take 6-12 months for a patient to get back to pre-surgical activity levels. A surgeon who is thoroughly experienced in hindfoot and ankle surgery should perform these procedures. The surgeon performing these types of procedures should have specialized continuing medical education, special postgraduate training and extensive experience with hindfoot and ankle surgery.

Surgical Management of Chronic Ankle Sprains

Chronic or repeated ankle sprains result from incompetence of the lateral collateral ankle ligaments. These ligaments function to support and control motion within the ankle joint. When these ligaments have been damaged from previous ankle sprains, they lose their ability to restrain the ankle joint within its normal range of motion. Typical symptoms include chronic ankle pain, difficulty walking on uneven surfaces or a feeling of the ankle "giving way". Initial treatment should consist of muscle strengthening and what is referred to as "proprioceptive rehabilitation". This can be accomplished through a physical therapist that is knowledgeable with rehabilitation of lateral collateral ligament instability. An ankle brace may also provide some external support to prevent recurrent injuries and also control swelling.

Surgical Stabilization of the Ankle

Surgery may be indicated for those cases of chronic ankle sprains failing to respond to conservative treatment. There are various surgical options available. These surgical procedures can be divided into two types. The first type involves the use of local tissue to reconstruct the lateral collateral ligament complex. The second type of surgery involves the use of a tendon graft or some other type of graft material to reconstruct the lateral collateral ligament complex.

The use of regional tissue is typically referred to as Brostrom-Gould procedure. This procedure is usually performed as an outpatient. This can be performed utilizing local anesthesia with IV sedation or a general inhalation anesthesia. The type of anesthesia depends on the surgeon and patient preference. Postoperative convalescence for this procedure includes approximately 4 to 6 weeks in a non-weight-bearing short leg cast. This is then followed by 2-3 weeks of protective weight-bearing in a camwalker or brace. The patient will then progress to standard footgear. This procedure has several advantages including the use of local tissue without sacrificing normal anatomic structures, very little restriction of normal range of motion and good cosmesis with the incision placement.

The second type of surgical procedure is referred to as a tenodesis procedure. This procedure involves a tendon or fascia latta graft that is routed through drill holes within the ankle and foot bones. This is usually performed as an outpatient and requires a general inhalation or spinal anesthesia. Postoperative convalescence includes 6 weeks of non-weight-bearing in a short leg cast. This is then followed by protected wirht-bearing in a camwalker or brace for 3 to 6 weeks. The patient will then return to standard footgear or rocker bottom brace depending on the extent of swelling. Some patients may require physical therapy but this will depend on the patient's specific situation. This procedure has the advantage of providing excellent stability. However, the stability can be at the expense of decreased joint motion and the sacrifice of normal anatomic structures to reconstruct the lateral collateral ligament complex.There are new allogenic grafts that have been developed. This allows the surgical procedure without utilizing normal anotomical structures. Ask your surgeon about this option.

Possible Complications

The major complications following lateral ankle stabilization procedure include decrease in subtalar joint motion. This joint is primarily responsible for the foot's ability to swivel side to side. The other complication not uncommonly seen includes sural neuritis. This is secondary to excessive traction of the sural nerve during the surgical procedure. Sural neuritis is usually transient and will resolve within one year.

Summary

Lateral ankle instability that fails to respond to non-operative care may require surgical management. The type of surgical procedure depends on the patient's activity level, occupation, weight and whether or not previous surgery has failed. The patient should discuss the various options with their surgeon to determine which procedure is best for their situation. The ultimate goal is to have a patient function at their pre-injury level and perform activities of a daily living without continued ankle sprains.