What is Ankle Fusion Surgery?
Ankle fusion surgery, also known as ankle arthrodesis, is a surgical procedure that fuses the ankle joint into a fixed position. During the surgery, the cartilage lining between the bones is removed and the bones are fused together with the help of metal plates and screws or sometimes an intramedullary nail placed inside the tibia and talus bones. This prevents any movement in the ankle joint and provides stability to the ankle.
Ankle fusion surgery is often recommended for patients who have severe ankle arthritis, injuries like ankle fractures that damage the joint beyond repair, or other conditions like rheumatoid arthritis that cause significant ankle pain and stiffness. By fusing the ankle bone, it eliminates pain from the damaged joint. The surgery immobilizes the joint and transfers stresses to adjacent less affected joints like the subtalar and midtarsal joints.
Types of Ankle Fusion Surgery
There are two main types of ankle fusion surgery - external fixation and internal fixation.
External Fixation
The external fixation method uses plates and screws on the outside of the ankle bones to fuse them. Metal plates are placed on the tibia and talus bones and held together with screws from the outside. This allows monitoring of wound healing from the outside. However, it requires pin sites and has risks of pin site infections.
Internal Fixation
In internal fixation, also called intramedullary nailing, a hollow metal nail called an ankle fusion nail is inserted inside the tibia bone from the knee down and across the ankle joint into the talus bone. The nail acts as an internal splint to fuse the bones together internally. This technique provides strong fixation and early weight bearing. It has advantages like protected wound healing and fewer risks of infections compared to external fixation.
Surgical Procedure for Ankle Fusion Using Intramedullary Nail
Here are the key steps involved in ankle fusion surgery using an intramedullary nail:
- The patient is given general or spinal anesthesia and placed in a supine position. Antibiotics are administered before the surgery.
- An incision is made either anteriorly in front of the ankle or laterally on the outside.
- The cartilage between the ankle bones is removed using surgical tools to completely prepare the bony surfaces for fusion.
- A recess is created in the tibia and talus bones with the help of drills and reamers.
- An intramedullary nail of the appropriate size and length is inserted from the knee down through the recess in the tibia bone.
- The nail is advanced across the ankle joint and into the recess in the talus bone under fluoroscopic guidance.
- The position of the nail is checked using imaging to ensure proper alignment of the ankle.
- The incision is closed in layers with absorbable sutures. A sterile dressing is applied.
- A cast or removable boot is placed depending on the implant used for initial immobilization and weight bearing restrictions.
Benefits of Ankle Fusion over Ankle Replacement
While ankle replacement surgery is an alternative procedure to ankle fusion for end-stage arthritis, ankle fusion using an intramedullary nail has certain advantages:
- Fusion provides a more stable and rigid ankle joint compared to replacement implants that may loosen or fail over time requiring revision surgery.
- The surgery has a lower risk of complications and revision rates compared to complex ankle replacement procedures.
- Younger and more active patients are better candidates for fusion that can withstand stresses better than replacement joints.
- Fusion is more cost-effective than ankle replacement surgery and has greater long term survivorship.
- Replacement implants have limited life spans of 10-15 years while fusion provides a permanent solution.
- Nail fixation allows early weight-bearing post-surgery unlike replacement surgery requiring longer non-weight bearing.
So in summary, ankle fusion using a nail provides a durable, rigid solution for severely damaged ankles in suitable patients needing a definitive fix. It eliminates arthritic pain while restoring stability and mobility.
Recovery after Ankle Fusion Surgery
Recovery from ankle fusion surgery using a nail takes about 3-6 months. Here are the key steps:
- The leg is placed in a rigid cast or boot for 6-8 weeks to immobilize the fusion site allowing bones to initially knit together.
- Strict non-weight bearing is advised initially with progressive toe-touch weight bearing once fusion begins between 2-6 weeks.
- Regularity follow ups monitor fusion progress with x-rays every 4-6 weeks.
- Removable walking cast/boot is applied once solid fusion is seen on x-rays allowing full weight bearing around 3 months.
- Physiotherapy focuses on range of motion exercises of neighboring joints like subtalar joint to maintain mobility.
- Most patients can return to daily activities within 3-6 months but high impact exercises may take up to a year to resume once fusion is complete.
- The nail may be removed surgically later if causing discomfort otherwise often left permanently inside.
With diligent postoperative care and physiotherapy, ankle fusion using intramedullary nail can restore stability, improve mobility and alleviate pain from arthritis in the ankle joint. Though mobility is sacrificed at the fused ankle, overall function can be significantly improved.
Common Risks and Complications of Ankle Fusion Surgery
As with any surgery, ankle fusion also carries some risks and potential complications including:
- Delayed or non-union of bones requiring bone grafting - Seen in 5-10% cases.
- Infection of surgical site - Risk is low <3% with proper precaution.
- Nerve injuries - Temporary or permanent nerve injuries may occur near incision site.
- Implant failure or breakage - Rare, especially with locked intramedullary nails.
- Adjacent joint problems - Increased stress on neighboring joints like subtalar joint over time.
- Blood clots in legs (DVT) - Low risk with preventive measures like stockings and early mobility.
- Stiffness in neighboring joints like subtalar joint if over-immobilized during recovery.
Proper patient selection, meticulous surgical technique and rehabilitation can help minimize risks and complications after ankle fusion with intramedullary nailing. Many newer generation implants also address some past concerns.