Ankle arthrodesis: A systematic approach

Ankle arthrodesis is a common treatment for patients with severe ankle arthritis. The goal of this surgery is to create a solid connection between the bones of the ankle, ensuring proper alignment and allowing for pain-free movement during weightbearing activities. There are different methods for performing ankle arthrodesis, including various surgical approaches and fixation techniques, each with its own advantages and disadvantages.

The success of ankle arthrodesis depends on several factors, such as patient selection, the surgeon’s expertise, any other health issues the patient may have, and the care received during and after surgery. However, in our experience, most patients with severe ankle arthritis achieve positive results with this procedure.

This review aims to explain when ankle arthrodesis is recommended and what goals it aims to achieve. We’ll discuss both traditional open surgery and newer arthroscopic techniques, providing a detailed step-by-step guide for each procedure and outlining the postoperative care plan. We’ll also look at the current evidence supporting these approaches and discuss the latest findings on patient outcomes and potential complications, such as the development of arthritis in other parts of the foot.

Ankle arthrodesis and ankle arthroplasty are two common surgeries for severe ankle arthritis. Recent studies suggest that ankle arthroplasty may offer better movement and function after surgery compared to ankle arthrodesis. However, ankle arthroplasty also comes with higher risks of complications and needing additional surgeries. Despite the growing popularity of ankle arthroplasty, ankle arthrodesis remains the most commonly performed surgery for severe ankle arthritis.

There are different techniques for ankle arthrodesis, including open surgery or using a small camera called an arthroscope. Both methods can lead to successful outcomes, but reported results vary due to differences in techniques, surgeon expertise, patient selection, and how outcomes are measured. Ankle arthrodesis should be carefully considered for young, highly active patients, and those with advanced foot and ankle problems.

Ankle arthrodesis is recommended for patients with severe ankle arthritis who haven’t improved with at least three months of non-surgical treatments. The goal of this surgery is to provide a foot that is free of pain during activities like walking. Proper alignment of the ankle joint is crucial, with a slight outward tilt, normal bending, and slight outward rotation. Poor alignment can lead to foot pain and changes in how you walk. It’s also important to minimize any differences in leg length after surgery to avoid problems with walking.

Arthroscopic ankle arthrodesis is usually best for patients with minimal joint deformity, while open surgery is better for those with more severe deformities. Before fusion of the ankle joint, it’s essential to make sure the front of the foot is balanced and not leaning too much inward or outward. If there are significant alignment issues, skin problems, leg length differences, or a history of infection, the surgeon may recommend a combination of cleaning out the joint and using an external device to stabilize the foot.

 

Surgical techniques

Many different surgical techniques are available for ankle arthrodesis, and the choice depends on factors like the patient’s condition, goals of treatment, and what the surgeon prefers.

Approach: There are two main approaches to ankle arthrodesis: open and arthroscopic. Open surgery can be done from different angles: front, back, side, or a combination of these. It’s good for correcting alignment problems and using plates and bone grafts, but it can lead to more wound complications and longer recovery times. Arthroscopic surgery is less invasive and quicker, but it’s usually only suitable for patients with minimal deformity or higher risk of wound problems.

Fixation methods: Internal fixation uses screws, plates, or nails to hold the bones together. Screws are commonly used because they’re simple, have fewer complications, and are cheaper. However, they may not work well in weak bones. Plates are sturdier but can increase the risk of infection. Sometimes a combination of screws and plates is used for added strength. Nails are usually reserved for severe cases involving both ankle and subtalar joints. This is because the subtalar joint is important for stability during walking, and fusing it can affect how you walk.

External fixation is another option, mainly for patients with complex issues like bone defects, leg length differences, or previous infections. However, it tends to have lower success rates compared to internal fixation methods.

There are two main ways to perform ankle arthrodesis for severe ankle arthritis: open surgery and arthroscopic surgery. Both methods involve fixing the joint with screws and then keeping the foot still in a cast for about six weeks. We’ve had good results with both approaches.

 

Open surgery with screw fixation:

First, the patient lies down with their feet at the edge of the bed, and a tight band is put around the thigh to reduce bleeding. The surgeon prepares all the necessary tools. The surgery starts with marking key points on the skin, like the bones around the ankle and important nerves. Then, a curved cut is made on the outside of the ankle and another cut along the inside of the ankle. Next, the surgeon carefully cuts a piece of bone from the fibula (the smaller bone in the leg) near the ankle.

This piece of bone is kept aside to use later. After that, the surgeon cleans out the ankle joint to remove any damaged tissue. The goal is to expose the bones so they can grow together. The surgeon then uses special screws to fix the bones in the right position.

These screws are carefully placed to make sure the bones stay in the correct alignment. Sometimes, additional screws are needed to fix the bones on the outside of the ankle. Finally, bone graft (extra bone material) may be added around the fusion site to help the bones heal together.

This surgery aims to relieve pain and improve function in the ankle, allowing patients to return to their normal activities. It’s important to follow the post-operative instructions carefully for the best results.

 

Arthroscopic Ankle Arthrodesis with Screw Fixation

Patient Positioning and Equipment: To perform arthroscopic ankle arthrodesis, specialized arthroscopy equipment is needed, including a small camera called an arthroscope and tools for cleaning and fixing the joint. The patient is positioned lying down with the leg supported by a special holder, and the ankle is held in place with a strap.

Arthroscopic ankle arthrodesis is a minimally invasive procedure that allows for faster recovery compared to traditional open surgery. It’s a safe and effective option for patients with ankle arthritis who haven’t responded to other treatments. Following the surgery, patients need to follow their surgeon’s instructions for post-operative care to promote healing and prevent complications.

 

Biologics for Ankle Fusion

What are Biologics? Biologics are substances used to help the ankle bones fuse together during surgery. There are two main types: osteoconductive and osteoinductive agents.

Osteoconductive Agents: These substances act as a scaffold at the fusion site, providing a framework for new bone formation. Examples include bone allografts and demineralized bone matrix.

Osteoinductive Agents: These substances directly stimulate bone growth, often by containing growth factors or stem cells. Examples include bone morphogenetic proteins and platelet-rich plasma.

How are Biologics Used? Biologics are placed into the fusion site before and after the final placement of screws to enhance bone healing.

 

Postoperative Rehabilitation

Initial Immobilization: After surgery, the ankle joint is placed in a non-weightbearing cast for six weeks to allow for initial healing.

Transition to Walking Boot: Following the cast removal, patients are fitted with a Controlled Ankle Movement Walker Boot to gradually transition to weightbearing.

Monitoring and Gradual Increase in Activity: Regular X-rays are taken to monitor the fusion progress at intervals of 6 weeks, 3 months, 6 months, and 1 year. Patients are advised to gradually increase weightbearing by 10% every two weeks. Once complete fusion is confirmed on X-rays, patients may resume full weightbearing.

Importance of Follow-Up: It’s essential for patients to attend follow-up appointments and adhere to the rehabilitation plan to ensure successful fusion and recovery.

 

Research on Ankle Fusion

Measuring Success: One common way to measure success in ankle fusion is by looking at the union rate, which shows how well the bones have healed together. Other measures used in these studies include scoring systems like AOFAS, Duquennoy, Mazur, Takakura, Foot Function Index, and Olerud and Molander.

What the Studies Found: The average union rate for open fusion was 89%, ranging from 64% to 100%. For arthroscopic fusion, it was 94%, ranging from 70% to 100%. In studies comparing the two methods, the union rates were similar, with 89% in the open group and 91% in the arthroscopic group. However, one study by Townshend et al. found only a slight improvement in clinical outcomes with arthroscopic fusion.

Effects on Driving: Research by Jeng et al. showed that ankle fusion could decrease the time it takes to brake while driving. However, this delay in braking time still falls within safe limits set by the US Federal Highway guidelines. Another study by Schwienbacher et al. found that people who had ankle fusion had slightly more difficulty braking in emergency situations compared to healthy individuals, as shown in driving simulator tests.

 

Conclusion:

Ankle fusion is a successful treatment for end-stage ankle arthritis (ESAA) and can be done using either an open or arthroscopic approach. There are different ways to fix the bones together, but the authors usually prefer using two to three screws. Right now, it’s hard to say for sure whether open or arthroscopic fusion is better for ESAA because there are conflicting studies. Since the success of fusion depends on many factors, this review aims to give the most recent information to help improve the outcomes of ankle fusion surgeries.

A seasoned orthopedic surgeon and foot and ankle specialist, Dr. Mohammad Athar welcomes patients at the offices of Complete Orthopedics in Queens / Long Island. Fellowship trained in both hip and knee reconstruction, Dr. Athar has extensive expertise in both total hip replacements and total knee replacements for arthritis of the hip and knee, respectively. As an orthopedic surgeon, he also performs surgery to treat meniscal tears, cartilage injuries, and fractures. He is certified for robotics assisted hip and knee replacements, and well versed in cutting-edge cartilage replacement techniques.
In addition, Dr. Athar is a fellowship-trained foot and ankle specialist, which has allowed him to accrue a vast experience in foot and ankle surgery, including ankle replacement, new cartilage replacement techniques, and minimally invasive foot surgery. In this role, he performs surgery to treat ankle arthritis, foot deformity, bunions, diabetic foot complications, toe deformity, and fractures of the lower extremities. Dr. Athar is adept at non-surgical treatment of musculoskeletal conditions in the upper and lower extremities such as braces, medication, orthotics, or injections to treat the above-mentioned conditions.