Ankle arthrodesis, also referred to as ankle fusion, is a commonly performed surgical procedure used most often for the treatment of end-stage ankle arthritis . Ankle arthrodesis was first described by Albert is 1879, involving attempted fusion without fixation [1]. In 1951, Charnley described his experiences with both ankle and shoulder arthrodesis, introducing the concept of compression for ankle joint fusion [2]. For the ankle, this was accomplished through an anterior transverse incision , flat cuts made for the tibial and talus, followed by application of a spanning external fixator. Charnley reported the outcomes of 19 patients, gaining a bony union in fifteen of them and painless fibrous union in the remaining four patients. In his paper, he describes the challenge of obtaining a successful fusion, writing that “with compression arthrodesis in the ankle it would appear that this joint does not possess the same natural potential for bony union as exists in the soft cancellous bone of the knee.” He also cautioned that “the writer does not wish to minimise the fact that the methods [of ankle fusion] perhaps demand a little more mechanical aptitude than is necessary in most orthopedic procedures.” Charnley’s emphasis on compression as a method to achieve bony union is a principle that has endured. Modern techniques of ankle fusion rely upon compression, more commonly now with internal fixation devices that external fixation.

In the 1980s, Mann popularized a utilitarian approach to ankle fusion [3]. This technique is a lateral trans-fibular approach that resects the distal fibula and enables bony apposition through flat cuts of the distal tibial and talus. Numerous additional approaches and techniques for ankle arthrodesis have since been described. These all rely upon four core principles, which in our opinion remain requirements for a successful outcome: apposition of viable bone surfaces, optimal ankle alignment, stable fixation, and compression. More recently, less invasive “mini-open” and arthroscopic techniques have been described. These approaches are attractive because they minimize wound complications and preserve vascularity to the articular surfaces undergoing fusion. Smaller incision approaches, however, can be technically challenging and are not appropriate for all patients, including patients with severe deformity. Open ankle arthrodesis therefore remains an essential tool for the treatment for end-stage ankle arthritis.

Ankle arthrodesis is most commonly performed as a treatment for end-stage ankle arthritis. Although substantially less common that arthritis of the hip and knee, ankle arthritis frequently develops after ankle trauma and can be debilitating. In addition to prior trauma, additional causes of end-stage ankle arthritis include inflammatory arthropathy, chronic instability, and less common conditions such as hemophilia, gout, neuroarthropathy, and septic arthritis. Patients with end-stage ankle arthritis typically report substantial pain that is worse with start-up and after increased activity. Pain may be present globally around the ankle or more focally, such as occurs if there are large anterior osteophytes that impinge with dorsiflexion.

The initial treatment of most patients with ankle arthritis is nonsurgical. Relief can often be provided with a structured nonsurgical approach, which may include weight loss, activity modification, and the use of a rocker-bottom shoe. Bracing options include a solid custom ankle-foot orthosis (AFO) or a prefabricated brace such as a carbon-fiber non-articulating AFO. Medications can be attempted as well, including oral or topical anti-inflammatory medications or intra-articular corticosteroid injection.

For those who do not derive adequate relief from nonsurgical management, the two most commonly performed surgical options are arthrodesis and total ankle replacement. A successful outcome, measured by substantially improved function and pain relief, can be achieved by both. Ankle arthrodesis is considered by many to be the tried and true treatment for end-stage ankle arthritis, yet arthroplasty is gaining popularity due to improved function and protection of the adjacent hindfoot joints. Some clinicians point to the risk of nonunion and the development of adjacent joint degenerative changes as reasons to favor arthroplasty over arthrodesis. Nonunion rates after arthrodesis reported in the literature range from 0% to 41%, but are thought to be less than 10% with contemporary fusion techniques. After ankle arthrodesis, adjacent joint degenerative changes are seen radiographically in nearly 100% of patients at 20 years [4]. This is thought to result from loss of the motion segment at the ankle with corresponding increased stress at the adjacent hindfoot joints. Ankle arthroplasty, however, is not without risk. Wound complications , infection, and implant failure can be very challenging to manage. Determination of outcomes after ankle arthroplasty is difficult due to the wide variation of follow-up and differences of patient selection in the literature. A systematic review reported implant survival rates of 78% and 77% at 5 and 10 years, respectively [5]. It is thought that newer generation prostheses, which are designed to require less bone resection, may minimize the risk of implant failure.

While both ankle arthrodesis and ankle arthroplasty can be successful, careful patient selection and counseling is critical. Younger patients who need motion are more likely to require revision if they undergo arthroplasty and as such may be better served with arthrodesis. Meanwhile, older patients may not need the motion due to decreased mobility and therefore may not require a somewhat riskier ankle arthroplasty. Additional comorbidities that make an ankle arthroplasty more appealing than arthroplasty include severe deformity, neuropathy or neuroarthropathy, and talar osteonecrosis. In many patients, it is appropriate to outline the risk and benefits of arthrodesis and arthroplasty and then collectively select a treatment.

In addition to end-stage ankle arthritis , ankle arthrodesis can be an effective treatment for osteonecrosis, severe deformity, neuropathy, failed ankle arthroplasty, and severe instability.

An arthrodesis can be accomplished through several approaches: lateral trans-fibular (removing fibula), lateral fibular sparing, anterior, posterior, mini-open, and arthroscopically. Patient-specific factors, such as prior incisions and degree of deformity, often guide the selection of approach.

Both bone and soft tissue healing are required to achieve a successful outcome after ankle arthrodesis. Compromised soft tissues, as may be seen after prior burn injuries or extensive trauma, may negatively impact fusion rates. Similarly, smoking and poorly controlled diabetes, in our opinion, are both relative contraindications to ankle arthrodesis. These factors have been associated with poor outcomes after fusion , including higher rates of infection and decreased fusion rates [6]. As such, we routinely require our patients to quit smoking prior to surgery and will check serum nicotine and cotinine levels to ensure that patients are nicotine-free prior to surgery. In respect to glycemic control, we target a glycated hemoglobin (A1C) of less than 7.0% prior to surgery [7].

Active infection is problematic for proceeding with an ankle arthrodesis, and optimally the infection is cleared prior to a definitive arthrodesis procedure. Soft tissue infection, septic arthritis of the ankle, and periarticular osteomyelitis should be addressed with appropriate treatment including operative debridement and antibiotic therapy. If the extremity is rendered unstable due to loss of infected bone after debridement, application of a spanning ankle external fixator may be appropriate. In many circumstances, documented clearance of infection with improved clinical examination and normalization of inflammatory laboratory markers (i.e., ESR, CRP, WBC) guides the timing of subsequent attempted ankle arthrodesis. At times, an arthrodesis can be attempted simultaneous to clearing an infection. This is typically performed with an external frame, often a thin wire frame that gains compression across the joint while appropriate antibiotic therapy is administered.

Adequate stability is required to achieve bone healing across the tibiotalar joint . If bone loss at the distal tibia or talus precludes rigid fixation across the joint, then an extended arthrodesis such as a tibiotalocalcaneal arthrodesis should be considered. This is most often seen in the setting of severe trauma, infection, or osteonecrosis of the talus. Finally, a seemingly rigid construct with excellent fixation can fail due to poor postoperative weight-bearing compliance. We routinely send our patients to preoperative physical therapy to ensure that postoperative non weight-bearing restrictions can be safely adhered to.