Total Ankle Replacement, An Issue of Foot and Ankle Clinics, 1e (The Clinics: Orthopedics)

Novel Approaches in Total Ankle Replacement Surgery: A Comprehensive Examination

Introduction:

Total ankle replacement (TAR) has emerged as a viable surgical option for patients with severe ankle arthritis. This procedure offers the potential for pain relief, improved mobility, and a return to active lifestyle. However, understanding the nuances of TAR surgery, including the complexities of the ankle joint, implant designs, and surgical techniques, is crucial for successful patient outcomes.

Biomechanics of the Normal and Pathological Ankle Joint:

The ankle joint, composed of the talus, tibia, and fibula, plays a vital role in weight-bearing, stability, and locomotion. In healthy individuals, the ankle joint exhibits a complex interplay of bones, ligaments, and tendons, allowing for a wide range of motion. However, in pathological conditions such as rheumatoid arthritis, these structures can become inflamed and damaged, leading to pain, stiffness, and instability.

Ankle Arthrodesis versus Ankle Replacement:

In cases of severe ankle arthritis, patients face the decision between ankle arthrodesis (fusion) and TAR. While arthrodesis involves fusing the bones of the ankle to eliminate pain, it comes with the limitation of significantly reduced mobility. TAR, on the other hand, aims to preserve ankle motion while alleviating pain. The choice between these procedures depends on factors such as the severity of arthritis, patient activity level, and bone quality.

The Concept of Ankle Joint Preserving Surgery:

Recognizing the importance of preserving ankle motion, surgeons have developed techniques known as ankle joint preserving surgery (AJPS). These methods focus on restoring function and stability while minimizing damage to the surrounding joint structures. AJPS includes procedures such as:

• Ligament repair and reconstruction
• Osteochondral grafting
• Joint distraction arthroplasty

Issues in Treatment of Patients with Rheumatoid Arthritis:

Rheumatoid arthritis (RA) presents unique challenges in TAR surgery. The systemic nature of RA can affect multiple joints, making it essential to consider the overall health of the patient. Additionally, RA can lead to bone erosion and osteoporosis, which can compromise the stability and longevity of the ankle implant. Surgeons must carefully assess the condition of the bone and ligaments before proceeding with TAR.

Mobile and Fixed Bearing Prostheses:

TAR prostheses come in two primary designs: mobile bearing and fixed bearing. Mobile bearing prostheses allow for greater range of motion than fixed bearing prostheses, but they may be prone to dislocation and wear. Fixed bearing prostheses are more stable and durable, but they provide a more limited range of motion. The choice between these designs depends on the patient’s individual needs and preferences.

Techniques and Pitfalls with Specific Prostheses:

Different TAR prostheses have unique designs and techniques associated with them. Surgeons must familiarize themselves with the specific nuances of each prosthesis to optimize outcomes. For example:

• Salto prosthesis: The Salto prosthesis is a mobile bearing prosthesis that uses a unique “ball-and-socket” joint design. Proper positioning and alignment of this prosthesis are essential to avoid instability and wear.
• Hintegra prosthesis: The Hintegra prosthesis is a fixed bearing prosthesis that features a porous surface for bone ingrowth. Surgeons must carefully prepare the bone bed to ensure adequate integration of the prosthesis.
• Mobility Total Ankle Replacement: The Mobility Total Ankle Replacement is a mobile bearing prosthesis that offers a high range of motion. However, it requires precise balancing and ligament tensioning to prevent instability.

Treatment of the Arthritic Valgus Ankle:

Valgus ankle deformity, characterized by an inward deviation of the ankle, poses specific challenges in TAR surgery. Surgeons may employ techniques such as lateral column lengthening or medial column shortening to correct the alignment and improve outcomes.

Treatment of the Arthritic Varus Ankle:

Varus ankle deformity, characterized by an outward deviation of the ankle, requires a different set of surgical techniques. These may include medial column lengthening or lateral column shortening to restore alignment and stability.

Revision Total Ankle Replacement:

In some cases, TAR surgery may fail, necessitating revision surgery. This can be a complex procedure due to the presence of scar tissue and bone loss. Surgeons may need to use specialized techniques, including bone grafting and revision prosthetics, to achieve satisfactory outcomes.

Salvage Arthrodesis after Failed Total Ankle Replacement:

If revision TAR surgery fails, salvage arthrodesis may become necessary. This involves fusing the ankle joint to eliminate pain and provide stability. Surgeons must carefully assess the condition of the joint and surrounding structures to determine the appropriate technique for salvage arthrodesis.

Managing Specific Complications Related to Total Ankle Replacement:

TAR surgery carries the potential for various complications, including:

• Infection
• Instability
• Loosening
• Nerve damage

Surgeons must be vigilant in identifying and managing these complications promptly to minimize their impact on patient outcomes.

The New Zealand Total Ankle Registry:

The New Zealand Total Ankle Registry collects data on all TAR procedures performed in New Zealand. This registry provides valuable information on implant performance, surgical outcomes, and complications. It serves as a resource for surgeons to evaluate and improve their techniques.

Conclusion:

Total ankle replacement surgery offers a promising option for patients with severe ankle arthritis. Understanding the biomechanics of the ankle joint, the nuances of implant designs, and the complexities of surgical techniques is essential for successful patient outcomes. By embracing a comprehensive approach that addresses the unique needs of each patient and employing the latest advancements in surgery, surgeons can maximize the benefits of TAR and improve the quality of life for those suffering from ankle arthritis