Ankle Replacement (Total Ankle Arthroplasty): Procedure, Candidates, and Recovery

Can you replace an ankle?

Yes, it is possible to surgically replace an ankle joint through a procedure known as total ankle arthroplasty (TAA), which involves removing damaged bone and cartilage and implanting prosthetic components.

Understanding Ankle Replacement (Total Ankle Arthroplasty)

Total ankle arthroplasty (TAA), commonly referred to as ankle replacement surgery, is an orthopedic procedure designed to alleviate pain and restore function in a severely damaged ankle joint. Unlike ankle fusion (arthrodesis), which permanently joins the bones of the ankle to eliminate motion, TAA aims to preserve or restore a degree of movement while providing significant pain relief. The procedure involves the precise removal of the diseased portions of the tibia (shin bone), fibula (smaller lower leg bone), and talus (ankle bone), which form the ankle joint. These damaged surfaces are then replaced with artificial components, typically made of metal and a high-density polyethylene (plastic) spacer, mimicking the natural joint's structure.

Why Ankle Replacement is Performed: Indications

The primary reason for undergoing total ankle arthroplasty is severe, debilitating ankle arthritis that has not responded to conservative treatments. Arthritis causes the cartilage cushioning the ends of the bones to wear away, leading to bone-on-bone friction, pain, stiffness, and loss of mobility.

Common indications for TAA include:

• Osteoarthritis: Often a result of long-term wear and tear, or more commonly, a history of ankle injuries (post-traumatic arthritis).
• Rheumatoid Arthritis: An autoimmune disease that causes chronic inflammation of the joints, leading to cartilage destruction.
• Other Inflammatory Arthropathies: Conditions like psoriatic arthritis or ankylosing spondylitis affecting the ankle.
• Avascular Necrosis of the Talus: A condition where the bone tissue dies due to a lack of blood supply, often leading to collapse and arthritis.
• Failed Ankle Fusion: In some cases, patients who have previously undergone ankle fusion may be candidates for conversion to an ankle replacement if they experience pain in adjacent joints or other complications.

Candidates for TAA typically experience significant pain that limits daily activities, functional impairment, and have exhausted non-surgical options such as physical therapy, bracing, anti-inflammatory medications, and injections.

The Surgical Procedure: What to Expect

Total ankle arthroplasty is a complex orthopedic surgery performed under general or regional anesthesia. The specific approach can vary based on the surgeon's preference and the patient's anatomy, but generally involves:

• Incision: An incision is made on the front or side of the ankle to access the joint.
• Bone Resection: The damaged ends of the tibia and talus are carefully cut and removed using specialized instruments. The goal is to create precise surfaces for the prosthetic components.
• Implant Placement: Metal components are then secured to the prepared bone surfaces of the tibia and talus. These are often porous-coated to encourage bone ingrowth for long-term stability.
• Polyethylene Spacer: A durable plastic (polyethylene) component is inserted between the two metal implants, acting as the new cartilage surface, allowing smooth articulation.
• Closure: The incision is closed in layers, and the ankle is typically immobilized in a splint or cast.

The surgery usually takes 1.5 to 3 hours, and patients typically remain in the hospital for a few days post-operation.

Who is a Candidate for Ankle Replacement?

While TAA can offer significant benefits, it is not suitable for everyone. Patient selection is crucial for optimal outcomes.

Ideal candidates generally possess:

• Severe Ankle Arthritis: As outlined above, with persistent pain and functional limitations.
• Failed Conservative Treatment: All non-surgical options have been tried without adequate relief.
• Sufficient Bone Stock: Adequate bone quality to support the implants.
• Good Overall Health: No active infections, uncontrolled diabetes, severe peripheral vascular disease, or other conditions that could compromise healing or increase surgical risks.
• Realistic Expectations: Understanding the limitations of the procedure, including the need for activity modification post-surgery. Ankle replacements are generally not recommended for high-impact sports.
• Commitment to Rehabilitation: Willingness to diligently follow a post-operative physical therapy program.

Contraindications (reasons not to perform TAA) may include:

• Active infection in the ankle or foot.
• Significant peripheral neuropathy (e.g., severe diabetic neuropathy).
• Charcot arthropathy (a progressive degenerative joint disease).
• Severe osteoporosis.
• Poor blood supply to the foot and ankle.
• Unstable ankle joint due to ligamentous laxity.
• Significant deformity that cannot be corrected with the replacement.

Benefits of Ankle Replacement

For appropriate candidates, total ankle arthroplasty offers several compelling advantages over other treatment options like ankle fusion:

• Pain Relief: The primary benefit, often leading to a significant reduction or complete elimination of chronic ankle pain.
• Preservation of Motion: Unlike fusion, TAA maintains a functional range of motion in the ankle, which can reduce stress on adjacent joints (like the knee and subtalar joint), potentially preventing secondary arthritis in those areas.
• Improved Function and Mobility: Patients often experience improved gait, ability to perform daily activities, and participate in low-impact recreational activities.
• Enhanced Quality of Life: Reduced pain and improved mobility contribute to a better overall quality of life.

Potential Risks and Complications

As with any major surgery, total ankle arthroplasty carries potential risks and complications, though serious complications are relatively rare.

Potential risks include:

• Infection: Can range from superficial wound infections to deep joint infections, potentially requiring further surgery or implant removal.
• Nerve Damage: Temporary or permanent numbness, tingling, or weakness in the foot.
• Blood Clots: Deep vein thrombosis (DVT) in the leg, which can potentially travel to the lungs (pulmonary embolism).
• Fracture: Fractures of the bones around the implants during or after surgery.
• Component Loosening or Failure: The implants may loosen over time, requiring revision surgery.
• Continued Pain or Stiffness: While pain relief is a primary goal, some patients may still experience discomfort or limited motion.
• Wound Healing Problems: Especially in patients with diabetes or vascular issues.
• Non-Union or Mal-Union: Bones not healing correctly or healing in an incorrect position.
• Need for Revision Surgery: The lifespan of an ankle replacement is typically 10-15 years, but can vary widely. Revision surgery may be needed if components fail or complications arise.

Post-Operative Rehabilitation and Recovery

Rehabilitation is a critical component of a successful ankle replacement outcome. It is a structured, progressive process that begins almost immediately after surgery and continues for several months.

Key phases of rehabilitation typically include:

• Initial Immobilization (0-2 weeks): The ankle is usually kept in a splint or cast, with strict non-weight-bearing. Focus is on wound care, pain management, and gentle, non-weight-bearing range of motion exercises (e.g., toe wiggles).
• Early Motion and Gradual Weight-Bearing (2-6 weeks): Once the incision is healed, a walking boot is often used. Gentle range of motion exercises for the ankle begin, along with partial weight-bearing as tolerated and directed by the surgeon.
• Strengthening and Proprioception (6-12+ weeks): As weight-bearing increases, physical therapy progresses to strengthening exercises for the ankle and surrounding muscles, balance training (proprioception), and gait retraining.
• Return to Activity (3-6+ months): Gradual return to light activities and exercise, avoiding high-impact sports. The full recovery process can take up to a year or more.

Adherence to the physical therapy program is paramount for regaining strength, flexibility, balance, and functional mobility.

Ankle Replacement vs. Ankle Fusion (Arthrodesis)

When faced with severe ankle arthritis, the two primary surgical options are total ankle arthroplasty (TAA) and ankle fusion (arthrodesis). The choice between them depends on various factors specific to the patient.

• Ankle Fusion: Involves surgically joining the bones of the ankle (tibia and talus) permanently. This eliminates all motion at the ankle joint, providing excellent pain relief and a very stable platform for weight-bearing. However, the loss of motion can place increased stress on adjacent joints, potentially leading to arthritis in the subtalar joint or other foot joints over time. It is often preferred for younger, more active individuals or those with significant bone loss or deformity.
• Ankle Replacement: Aims to preserve motion while relieving pain. It is generally favored for older, less active individuals, or those who wish to maintain more natural ankle mechanics. While it preserves motion at the ankle, it has a higher rate of potential complications and the implants have a finite lifespan, potentially requiring revision surgery in the future.

The decision is a complex one, made in close consultation with an orthopedic surgeon, considering the patient's age, activity level, specific type and severity of arthritis, bone quality, and overall health.

The Importance of Lifelong Ankle Care

Following an ankle replacement, lifelong care and adherence to post-operative recommendations are crucial for the longevity of the implant and continued ankle health.

Key aspects of lifelong care include:

• Activity Modification: Avoiding high-impact activities such as running, jumping, or aggressive sports that could prematurely wear out or damage the implant. Low-impact activities like walking, swimming, cycling, and elliptical training are generally encouraged.
• Maintaining a Healthy Weight: Reducing excess stress on the ankle joint.
• Appropriate Footwear: Wearing supportive, comfortable shoes that provide good cushioning and stability.
• Regular Follow-ups: Routine check-ups with the orthopedic surgeon to monitor the implant and ankle health, typically with X-rays.
• Adherence to Exercise Program: Continuing with prescribed exercises to maintain strength, flexibility, and balance.

By understanding the intricacies of total ankle arthroplasty and committing to the recovery and lifelong care process, individuals can often achieve significant pain relief and improved function, enhancing their quality of life.