Ankle Replacement
What is an ankle replacement ?
This operation replaces the arthritic joint with metal and plastic implant. Walking will be more normal, and the joint will remain mobile and mostly painfree; though joint movement is rarely better.
The newer ankle replacements have little long-term outcome data, though the 10 year results are encouraging with - 80-90% of operations remaining a success.
How is the surgery performed ?
The surgery is performed through a 15cm incision over the front of the ankle. The arthritic joint surfaces are removed and the tibia and talus are shaped to accommodate the implants. The implants are are uncemented and are coated with a special material (hydroxyapatite) that allows them to form a biological bone with the bone. The operation takes approximately 2 hours. After surgery, your leg will be immobilised in a backslab plaster cast for 2 weeks. You will remain in hospital at least 1 night.
What happens after the operation ?
The foot must be elevated (above the level of the pelvis) for 90% of the time for the first 10 days. This helps to reduce swelling and the risk of infection, and helps wound healing. Naturally, short periods of walking/standing are allowed but no weight must be taken through the operated leg for 2 weeks. After 2 weeks the backslab and the stitches are removed. The leg is then put into an Aircast boot for the next 4 weeks and this can be removed twice a day to perform range of motion exercises. Weight-bearing can begin at 4 weeks postoperatively if the wound has healed.
What are the risks of surgery ?
Stiffness & swelling.
Initially the foot will be very swollen and needs elevating. The swelling will disperse over weeks/months but may still be apparent at 6-9 months. Often shoes will remain tight for 8-12 weeks.
Infection.
There is always a risk of infection with surgery, and this is the biggest risk after joint replacement. Smoking increases this risk 16 times, and rheumatoid arthritis over 8 times. You will be given 1 dose of intravenous antibiotics during surgery, and 2 doses after surgery. The best way to reduce the chance of acquiring an infection is to keep the foot elevated for 10 days. If there is an infection it normally resolves with a course of oral antibiotics. Rarely it can be severe, requiring further surgery.
Nerve Damage.
Two nerves lie alongside the incision - the superficial peroneal and the saphenous nerves; and one deep inside the wound - the deep peroneal nerve. They supply sensation to the side and the top of the foot and toes, and the first web space. They may become damaged during the surgery and this will leave a patch of numbness, either at the side of the foot or over the top of the foot and toes. The numbness may be temporary or permanent. There is approximately a 10-15% of this happening.
Wear of the replacement.
The metal / polyethylene joint replacement has an unknown lifespan at present, though 10-15 years is a reasonable estimate. When it fails, it is either due to infection or to wearing away of the plastic component, which slowly occurs over many years. Once the joint wears out, further surgery is normally required to fuse the joint together.
Dislocation.
This is rare.
How much time will i need off work ?
4 weeks off work for sedentary jobs
6-8 weeks off work for standing/walking jobs
We will provide a sick note for the first 2 weeks; further notes can be obtained from the GP.
What are the usual follow up arrangements ?
2 weeks - Removal of sutures and change to Aircast boot.
4 weeks - Fully WB in an Aircast, Ankle Xrays. Physiotherapy referral.
3 months - Ankle Xrays
Article written by
Mr Henry Atkinson
Consultant Orthopaedic Surgeon
North London Sports Orthopaedics
Last updated 16/3/10 |
