Ankle Fusion (Arthroscopic)

Age, or more often past injury, can cause arthritis effecting the bones of the ankle and the tissues that cushion and lubricate their articulation. This operation removes the degraded parts of the joints joint and fixes the joint together using metal screws and shaped plates - with the aim that bone will grow across and 'fuse' the joint. The joint will then be rigid, but no longer painful.

Also known as Ankle Arthrodesis, fusing the ankle reduces the normal range of movement by around 50%, although often the majority of this has been lost already, due to the arthritis. Walking will be altered, but not noticeably on flat ground. Walking on slopes and stairs is the most apparent difficulty and driving requires the use of the leg to push the pedals rather than by flexing at the ankle.

The surgery is performed with key-hole technology, through 3 small incisions. The arthritic joint surfaces are excised (cut out) and the joint fixed together with screws. The operation takes approximately 1.5 hours. After surgery, your leg will be immobilised in a back-slab (half plaster) for 2 weeks.

Risks of surgery

Swelling

Initially the foot will be very swollen and needs elevating. The swelling will disperse over the following weeks & months but will still be apparent at 6-9 months.

Infection

This is the biggest risk with this type of surgery. You will be given intravenous antibiotics to prevent against it. The best way to reduce the chance of acquiring an infection is to keep the foot elevated for 14 days. If there is a mild infection, it often resolves with oral antibiotics. If the infection is severe, it may warrant admission to hospital and intravenous antibiotics. A severe infection often results in failure of the fusion, and extremely rarely may result in an amputation at a later date.

Malposition

Ideally, the ankle is fused in a position that al-lows optimum function and gives the best ap-pearance. I take great efforts to judge the best position for the fusion at surgery, but as you are asleep and lying down, it is not always possible to achieve this 'best' position. If the position is not optimal following surgery, most deformities can be accommodated by insoles and shoeware. Rarely is further surgery required.

Non Union

This is when the joint fails to fuse and bone has not grown across the joint. We won't know whether this is the case for 6-12 months. The risk of this is approximately 5%. Smoking increases this risk 4 times. If a non union does occur and is painful, then further surgery is usually needed.

Nerve Damage

Alongside the incision are two nerves – the superficial peroneal and the sural nerves. They supply sensation to the side and the top of the foot and toes. 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. This numbness may be temporary or permanent. There is approximately a 10-15% of this happening.

Recovery from surgery

Elevation of the foot (above the pelvis) for the first 10 days is vitally important to prevent infection. Naturally, small periods of walking and standing are necessary, but no weight must be taken through this leg for 6 weeks.

After 2 weeks the backslab will be removed and the stitches taken out, here in clinic. Another non-weight bearing plaster is applied for a further 4 weeks.

At this stage you will be reviewed in clinic with x-rays and changed to a protective boot for a further 6 weeks.

You will be reviewed again at 3 months following surgery, with x-rays. Usually no physiotherapy is required. If the fusion has not completely healed, then a further 6 weeks in a weightbearing cast will be necessary.

So, your approximate timetable is:

• 2 weeks: removal of sutures & Change of Plaster
• 6 weeks: Change to walker boot. AP & Lateral X-rays
• 3 Months: Final review. WB AP & Lateral X-ray. Mobilise Fully Weightbearing

Activity and time off work

This is more involved and significant surgery than many ankle procedures and accordingly it has a more extended recovery time.

In general, 4 weeks off work is required for sedentary posts, 12 weeks for standing or walking posts, 16 weeks for manual / labour intensive posts.

During the immediate post-operative period it is important to keep the fused ankle elevated to minimise swelling. Ideally this means keeping the ankle above the heart by lying down or sitting in a reclined position.

The tibia and talus require at least six to eight weeks before they are fused sufficiently to begin weightbearing – though it may take as long as 10 to 12 weeks. A variety of crutches, walkers, wheelchairs or knee scooters can be used to aid mobility.

After sufficient time has passed, you can slowly begin placing weight on the ankle using a walking boot. In some cases, physical therapy may help speed the transition to normal mobility.