Ankle Arthrodesis - An Overview

Introduction

Osteoarthritis of the ankle is age-related arthritis affecting the quality of life. In a normal and healthy ankle, the joints where the bones meet are covered by a protective pad called cartilage. The cartilage protects the bones. Due to various factors such as age, obesity, injury, repetitive stress, and genetics, the cartilage wears over time. This results in complete worn-off cartilage and bone-on-bone condition which results in a painful condition called osteoarthritis of the ankle. This condition accounts for about one percent of the world’s population. The conservative treatment options are given in the initial days. When the symptoms don’t improve, the patients are referred to the surgical management of the condition. This article will discuss fusion surgeries for ankle osteoarthritis.

What Is an Ankle Arthrodesis?

• The term arthrodesis refers to the surgical procedure which involves the fusion of one or more joints.

• The orthopedic surgeon removes the diseased cartilage, aligns the ends of the bone, and fuses them into a single bone by using metal internal fixation such as plates and screws.

• The ankle joint or talocrural joint is a hinged joint formed by the articulation of the tibia (shin bone), fibula (calf bone), and talus (foot bone) bone.

• The ankle joint is also formed by another joint called the subtalar joint where the talus and calcaneus bone (bone located below the ankle bone) articulates. Osteoarthritis of the ankle can affect these joints.

• Arthrodesis of the ankle involves the surgical fusion of two or more bones in the ankle joint.

What Is the Difference Between Ankle Arthroplasty and Arthrodesis?

Ankle arthroplasty also referred to as total ankle replacement surgery is used as an alternative to arthrodesis. In arthrodesis, there is the fusion of bones in the ankle joint and it is stabilized with no further movement in the joint, and the pain due to instability is treated successfully. In ankle arthroplasty, it involves the surgical replacement of the ankle with artificial prosthetics to preserve or retain some range of motion in the joint.

What Are the Indications for Ankle Arthrodesis?

The indications for performing ankle fusion surgery involve:

• Indicated in individuals with a failed total ankle replacement surgery.

• In post-traumatic osteoarthritis of the ankle joint.

• In patients with idiopathic end-stage osteoarthritis of the ankle joint.

• In patients with severe necrosis of more than 75% of the talus bone.

• In young and active patients.

• In patients less than 55 years of age.

• Presence of infection.

• In patients with no improvement toward non-surgical treatment.

What Are the Surgical Techniques for Arthrodesis?

• The surgical techniques for performing ankle arthrodesis are based on the goals of the treatment, the patient's characteristics, and the surgeon’s preference.

• The surgical techniques involve the conventional open technique with different approaches and the arthroscopic technique.

• The arthroscopic technique of performing ankle fusion surgery is the gold standard treatment of choice for ankle osteoarthritis with the less invasive procedure and requires minimal operative time.

• However, the open technique provides ease in applying internal fixation and less difficulty in correcting the misalignment and they are reserved for patients with moderate to severe deformities with healthy skin.

What Happens Before the Procedure?

• The orthopedic surgeon will explain the details and approach for the surgery to the patients and informed consent is obtained.

• The orthopedic surgeon along with other teams of healthcare professionals will perform the procedure.

• The patient is given either general anesthesia or spinal anesthesia by the anesthesiologist to make the patient sleep and not feel any pain.

• All the vital signs of the patient are assessed.

How Is Ankle Fusion Surgery Performed?

• Open Arthrodesis

  • During this procedure, the patient is positioned in a supine position.

  • The anatomical landmarks such as the lateral malleolus, medial malleolus, fourth and fifth metatarsal bone, sural nerve, and peroneal nerve are marked using a sterile marker.

  • The surgeon will make a hockey-shaped incision over the lateral aspect of the lateral malleolus.

  • Once the tibiofibular joint is identified, the surgeon performs surgical resection of the anterior inferior talo-fibular ligament, interosseous membrane, and interosseous ligaments. And surgical cutting of the distal fibula is performed.

  • Once the joint surface is fully exposed, the diseased cartilage is removed from the talus and tibia.

  • The tibiofibular joint is aligned in an optimal position.

    • With five to ten degrees of external rotation.

    • Neutrally dorsiflexed.

    • 0-5 degrees of slight valgus.

    • 5 millimeters of talar translation.

  • The adequate alignment is assessed through fluoroscopy.

  • The lateral malleolus is fused with the tibia with the help of guidewires and screws.

  • Bone grafts may be placed around the fusion site to enhance the union of two bones.

• Arthroscopic Arthrodesis

  • The patient is positioned in a supine position with ipsilateral flexion of the hip and supported by a leg holder.

  • The anatomical landmarks are marked using a sterile marker.

  • This procedure is performed using the anterolateral and anteromedial portals and occasionally with the posterolateral portal.

  • The surgeon creates the arthroscopic portals using the nic and spread technique.

  • A 2.7 to 4 mm arthroscopy is used.

  • Once the ankle joint surface is visualized, the diseased cartilage is removed using a burr, or curette.

  • The surgeon performs the tibiotalar fixation with the help of cannulated screws and Kirschner wire, once the adequate alignment of the talocrural joint is obtained.

  • The proper alignment of the joint is confirmed through arthroscopy and fluoroscopy.

After any surgical techniques, the patients are advised to be immobilized for the next six weeks and are given a short-leg cast.

What Are the Risks of Ankle Arthrodesis?

• Failure of the ankle bones to fuse.

• Arthrodesis may cause arthritis of the foot bone since it will increase the stress on the nearby joints.

• Infection of the surgical site.

• Misalignment of the bones.

• Bleeding.

• Damage to the nearby nerves or blood vessels.

• Blood clot.

Conclusion

Fusion surgery referred to as arthrodesis is the surgical fixation of two or more bones in a joint. Osteoarthritis of the ankle is a chronic age-related disease that affects the talocrural and subtalar joints of the ankle. Patients in the end stage of osteoarthritis who are not responding properly to the conventional non-surgical treatment options are referred for surgical arthrodesis. The main ultimate goal of the surgery is to provide a pain-free foot while performing daily and weight-bearing activities. Both open and arthroscopic arthrodesis have successful clinical outcomes.