Overview of Arthroereisis
“Arthroereisis” is a term that comes from two Greek words. “Arthro-” meaning ‘joint’ and “-ereisis” meaning ‘to brace or push against something’. In simpler terms, this procedure is a type of surgery used to address flatfoot problem. The goal of the surgery is to reconstruct the arch of the foot and control, but not fully stop, the movement of a joint in the foot, referred to as the subtalar joint, from rolling or tilting outward.
The idea of manipulating the subtalar joint to treat flatfoot was first introduced in 1946 by Chambers. He suggested a method called “manipulation” which involved inserting a piece of bone shaped like a wedge into a part of the foot known as the calcaneus. This was to stop a bone in the foot called the talus from moving too much forward on the calcaneus. This technique was known as an “abduction block”.
After a few years, Baker and Hill proposed a slightly different approach for the same problem. They suggested reshaping the joint surface on the side of the foot to achieve the same effect. Later on, Haraldsson suggested the idea of inserting a wedge-shaped piece of tissue into an area of the foot known as the sinus tarsi and named this the “arthrohisis”.
In 1970, Lelièvre introduced the term “arthroereisis” to describe a similar technique of placing bone graft in the sinus tarsi, which was temporarily held in place with a staple. The idea eventually evolved to include supporting the talus on the calcaneus by inserting an artificial implanted device in the sinus tarsi. In 1974, the first such device to accomplish this was suggested by Subotnick. Since then, a variety of different kinds of solutions have been introduced that differ in shape and material, such as polyethylene, silastic, titanium or a combination of these.
Anatomy and Physiology of Arthroereisis
Flatfoot is a common deformity where the foot seems to be entirely in contact or near contact with the ground. It involves specific changes in the foot such as the turning out of the forefoot, turning inward of the hindfoot, the medial (inner) arch of the foot flattening, and a downward shift of the talus, a bone in the ankle.
Experts often differentiate flatfoot in children and teenagers from flatfoot in adults, treating them as separate issues.
In children, it’s crucial to distinguish between two types of flatfoot: rigid and flexible. Rigid flatfoot often comes with symptoms and can be associated with conditions such as bony abnormalities, arthritis related to injuries or rheumatism, neurological or muscle disorders, or other underlying causes. Flexible flatfoot, on the other hand, is typically idiopathic (without a known cause) and the arch of the foot can restore itself when the child stands on their toes or bends their toes towards their shin. This type of flatfoot can often be corrected by a medical procedure known as arthroereisis.
Generally, flatfoot in young children is considered normal and often improves on its own by the time the child is around ten years old. Despite its common nature, it can sometimes cause concern for parents, leading to further medical examinations. Although children with flatfoot mostly walk without discomfort, some may experience pain in various parts of the foot including the lower part of the outer ankle bone, the inner middle part of the foot, and the inner side of the heel.
In adults, flatfoot, often identified through clinical and radiographic methods, is frequently associated with the weakening of the tibialis posterior tendon and is more common in African-American populations compared to Caucasian populations. Causes are usually divided into 3 categories: articular (like rheumatoid arthritis and connective tissue disease), osseous (congenital or posttraumatic abnormalities in bone), and neurological or muscle diseases.
Unlike in children, adult flatfoot is usually a permanent, acquired deformity that can lead to discomfort during everyday activities, difficulties in fitting shoes, and ongoing walking issues. Without proper treatment, these symptoms are likely to continue and potentially worsen over time.
Why do People Need Arthroereisis
If a child has painful congenital flexible flatfoot, a condition where the foot is excessively flat, they might need a procedure called subtalar arthroereisis. This can be done alone or alongside other surgeries. In this procedure, doctors insert an implant in a part of the foot known as the sinus tarsi (a space between two bones in the foot, the talus and calcaneus). This limits the excessive movement of the foot joint and helps correct flat feet. This procedure helps support the arch of the foot when weight is put on it and helps restore the arch when no weight is on the foot. It is commonly used alongside other treatments for inflexible flat feet caused by issues like tibialis posterior tendon dysfunction (a condition affecting a tendon in the calf), tarsal coalition (an abnormal connection of two bones in the foot), and accessory navicular bone syndrome (an extra bone or piece of cartilage located near the experience).
For adults with flatfoot, specifically those caused by tibialis posterior tendon dysfunction, the first treatment is usually insoles. Surgery like arthroereisis is only considered when simpler treatments don’t work. Although, arthroereisis’ role in adults differs from children due to the structural nature of adult flatfoot. While it’s rare for this procedure to be performed alone in adults, it’s frequently combined with other surgeries to enhance the antipronation effect (the inward roll of the foot while walking or running) and support the medial arch (the arch on the inside of the foot) and the tibialis posterior tendon. However, more research is needed to establish whether arthroereisis should be the primary option for managing adult flatfoot.
When a Person Should Avoid Arthroereisis
There are certain conditions that might prevent a person from undergoing arthroereisis, a surgery to correct flat feet:
Firstly, if someone has an “unstable midtarsal joint”, a condition that often occurs with flexible flatfoot, arthroereisis might not be suitable. In these patients, the foot implant used during surgery could cause discomfort, or even worse conditions, like the foot joint slipping out of place (subluxation) or arthritis. This is because the implant puts a lot of strain on the midtarsal joint. In this situation, the patient might need a different surgery called osteotomy or midtarsal arthrodesis.
Secondly, if a patient has arthritis in the subtalar or midtarsal joints in their foot, the foot implant might make the inflammation and the wearing down of the joint cartilage even worse. The foot implant can also mess with the normal movement of the joint and cause more damage. Arthritis could also affect how the foot implant is fixed in place and how stable it is, which can increase the risk of the foot implant failing or moving. Arthroereisis is not suitable for patients with arthritis. Instead, they may need a different treatment like joint debridement, arthroplasty, or arthrodesis.
Lastly, people with “rigid equinus”, a condition where the ankle joint is fixed in a certain position, might not respond well to arthroereisis. This is because this condition puts a lot of pressure on the front of the foot, and the normal arching of the foot could collapse. Arthroereisis helps by restricting foot joint movement, but it doesn’t address the issue of the fixed ankle joint, which could make their symptoms even worse. As a result, patients with rigid equinus might need a combination of treatments, like making a small cut in the calf muscle (gastrocnemius recession) or lengthening the Achilles tendon, in addition to arthroereisis.
Equipment used for Arthroereisis
Arthroereisis, a surgical procedure meant to improve foot function, uses different types of inserts and techniques. Some of these include expandable implants placed in the sinus tarsi (a tunnel between two bones in the foot), lateral calcaneus stop screws (screws applied to the outer part of the heel bone), and implants that can be absorbed by the body over time. In a recent study, these three methods were compared based on their effects on foot function, alignment (how the foot is positioned), and pressure distribution (how weight is spread across the foot).
The study found that all three methods had similar positive effects on these outcomes. However, the use of sinus tarsi implants was found to have a higher risk of complications related to the implant when compared to the screw arthroereisis (inserting screws to limit joint movement).
How is Arthroereisis performed
If your doctor has recommended an arthroereisis procedure, it’s likely they will use a minimally invasive surgical technique. This method is generally favored because it requires only a small cut, about half an inch to an inch and a half long. This cut is made on the outer side of your ankle, just slightly below and in front of the bony bump on the outside of your ankle – this is known as the lateral malleolus. The surgeon will then clean out (debride) the part of your foot called the sinus tarsi, before manually moving your foot from a rolled inward (pronated) position to a straight, or ‘supinated,’ position.
If your surgery uses self-locking implants, the surgeon will insert a probe into the cut to figure out the best direction for the implant. Then they’ll use a series of differently sized trial implants under the guidance of a special type of X-ray called fluoroscopy, to figure out the best fit. If your surgery requires impact-blocking instruments, like the ‘calcaneo-stop’ screw, the surgeon will insert a guide wire after drilling into either the talus (a bone in the ankle) or the heel bone (calcaneus), before inserting the screw.
After the surgery, your doctor will give you instructions for your recovery. This will change depending on your individual circumstances and if you had any other procedures done at the same time. For example, if you have other operations alongside the arthroereisis, you might not be able to put weight on your foot for around six weeks. However, if you only had the arthroereisis, you might be able to start weight-bearing immediately after the surgery. In this case, it’s common to wear a cast or some form of foot and ankle support for around 5 to 10 days.
Possible Complications of Arthroereisis
Arthroereisis is a type of foot surgery that can sometimes have complications. These complications can be grouped into four main categories: issues with the implant used during surgery (like it coming loose or breaking); an inflammatory reaction (such as soreness, muscle spasms, or fractures); technical errors during surgery (like putting the implant in the wrong place); and complications that happen when the surgery is performed in cases where it’s not recommended (such as when the patient has arthritis).
The most usual complication with this type of surgery is pain around the sinus tarsi (the area on the outside of the foot around the ankle), but this usually gets better if the implant is taken out. Still, there’s a lot of uncertainty about how often complications and implant removals happen. Different studies say different things, with reported complication rates ranging from roughly five to just under twenty percent, and removal rates from seven to nearly twenty percent. What’s more, some issues might get better on their own and don’t always need extra surgery.
Some rare but serious issues have been reported, such as a fracture of the talus (one of the bones in the foot) or having to fuse bones together after surgery. However, recent studies suggest a fairly low overall complication rate (from 0% to 11%). However, in a 2015 survey, a third of participating American foot and ankle surgeons said they had stopped performing this type of surgery because of a high failure rate and the need to remove the implant. This survey showed that arthroereisis is more commonly performed by non-American surgeons, which could be because of the difficulty in getting payment from health insurance companies in the United States.
Earlier research seems to suggest that the implant used in the surgery should remain in place for at least two years to allow the bone and soft tissues to adjust before it’s removed. Some studies suggest a delay of six to eighteen months, especially when the surgery is performed alongside other procedures in adults for the condition of flat feet. But there is no exact timeframe for when an implant should be removed permanently. Studies looking into the predictors for implant removal in adults have found that up to 30% to 40% of implants have to be taken out earlier than planned. The chance of this happening can increase if the foot deformity hasn’t been fully corrected or if the implant is larger than usual. It’s still unclear how these risk factors affect the chance of having to remove the implant, and this needs further investigation.
What Else Should I Know About Arthroereisis?
Arthroereisis is a type of surgery that has many benefits compared to more traditional methods. One of the most important is that it is a less invasive technique. This means that it requires smaller cuts and causes less damage to the soft tissues in your body. Because of this, patients often have shorter hospital stays, recover quicker, and experience fewer problems after the operation, like swelling and pain.
Another big advantage of arthroereisis is that it helps to keep the natural structure and movements of the foot. This is particularly beneficial as it allows for future growth and development. Importantly, this type of surgery can be reversed, and the implant that is inserted can be easily taken out if needed, giving more flexibility in treatment choices.
However, like with any medical procedure, arthroereisis comes with potential issues. Complications related to the implant and potentially needing to remove the implant at a later date may arise. Therefore, it’s important for doctors to carefully choose patients who are good candidates for this procedure and to take care of them well after the surgery to ensure the best results. With that being said, arthroereisis is an important option for treatment in managing flatfoot deformities in both children and adults, helping to improve the functionality of the foot and patients’ quality of life.
