Ankle Fusion Surgery

Background: Ankle Arthritis

Arthritis is a process which results in damage to the normally smooth articulating surfaces of a joint, resulting in pain, stiffness and often swelling. Arthritis damages the highly specialized cartilage which lines the end of bones allowing smooth joint movement. Arthritis can occur in any of the joints of the foot and ankle but is most common in the big toe joint, midfoot, and ankle.

The arthritic process can cause inflammation of the joint and over time can sometimes lead to deformity. There are various different types of arthritis, some occurring in a single joint as a result of previous injury and others occur in more than one joint as a result of inflammatory problems for example.

Symptoms of Arthritis in the Foot & Ankle

Arthritis can occur in a joint without any noticeable symptoms. However, as it progresses, patients often report symptoms of stiffness, pain, swelling, and later on, deformity can occur. Some patients will develop a bony prominence called an osteophyte (“bone spur”). This can cause pinching of the lining of the joint (synovium) which is called impingement. Gradually, these symptoms can limit activity and when more advanced, patients can begin to report symptoms even when resting or in bed at night.

Treatment of Arthritis in the Foot & Ankle

Treatment such as footwear modification, anti-inflammatory medication and physiotherapy can be very effective. Sometimes injections (cortisone) can help to damp down inflammation. If these treatments are insufficientthen surgery may be necessary and can be very successful.

Surgery in the earlier stages of arthritis may be “keyhole” (arthroscopy). Mr Redfern has developed a specialist practice in keyhole techniques including arthroscopy which allows the surgeon to operate using a tiny camera inside a joint. This allows the surgeon to assess and treat the joint from the inside with minimally invasive surgery. The joint can be tidied up if the arthritic process is not too advanced but is not a cure for the condition.

In more advanced arthritis the surgeon may recommend that the joint is fused or replaced. Fusing the joint effectively removes the painful joint surfaces and joins the two surfaces of the bone together (permanently stiffening the joint). Sometimes this can also be performed by keyhole surgery. Replacing the joint may also be an option in advanced arthritis and this involves replacing the painful worn joint surfaces with artificial joint bearings made of highly specialised metals and/or polyethylene. (see specific information sheets for joint fusion and joint replacement).

Ankle Fusion (Arthrodesis)

The goal of this type of surgery is to glue together (fuse / arthrodese) the painful and arthritic ankle joint.  This is generally offered to patients for severe painful arthritis and/or deformity.

The joint will then be rigid and, in the majority of patients, no longer painful. 

This reduces the normal movement by 60-70% although the majority of this motion has often already been lost due to the arthritic process which tends to gradually stiffen the joint. Walking pattern will be altered, but not usually noticeably on flat ground (walking pattern usually improves after this type of surgery due to the abolition of pain).  Walking on slopes and stairs is different after ankle fusion and driving requires a different technique with pushing of the pedals using the leg rather than pushing them by bending the ankle.

In the vast majority of patients the surgery is performed by Mr Redfern via a ‘keyhole’ technique (arthroscopic fusion) which involves two small incisions (1cm) over the front of the ankle and two small incisions (2cm) over the inside of the ankle / leg. Through these keyholes, the joint can be visualised using fibre-optic technology and the joint surfaces prepared using mini instruments. Screws are then guided across the joint (using xray screening) fixing it in the desired position for fusion. Once the joint is fused the screws are redundant but are rarely removed.

Sometimes, if there is severe deformity a more traditional ‘open’ surgical technique has to be used with a 15 cm incision over the outer side of the ankle. The arthritic joint surfaces are excised (removed) and the joint fixed together with screws in a similar fashion. The operation takes approximately 1.5 hours.

General Recovery Facts:

Arthroscopic Ankle Fusion

• You will be in a cast / removable boot for 3 months after surgery

• You will not be taking weight on the operated leg for ~6 weeks

• After six weeks you can partial weight bear (~ 40% body weight)

• Crutches / frame / walker required for 3 month

• There will be some persisting swelling for 6 months after surgery

• Your strength will continue to improve up to 9 months after surgery

• You can expect some soreness / aching for approximately 4 months after surgery

• Driving is usally not possible until 3 months post surgery unless surgery to left foot only and automatic vehicle.

Non-operative alternatives to ankle fusion surgery

Your surgeon may have discussed the following with you:

1.   Oral analgesics (pain relieving medication)

2.   Activity modification (reducing activity which brings on symptoms)

3.   Custom orthotics (insoles)

4.   Modified footwear 

5.   Ankle foot orthosis (AFO) - brace

6.   Steroid injection

Main Risks Of Ankle Fusion Surgery:

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

Infection – this risk is very small with the arthoscopic type of surgery (~1:200).  Smoking increases the risk 16 times.  You will be given intravenous antibiotics to help prevention. However, keeping the foot elevated over the first 10 days helps reduce this risk.  If there is an infection, it may resolve with a course of antibiotics but often results in failure of the fusion.  

Mal-position – ideally, the ankle is fuse in a position that allows optimum function and gives the best appearance. 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 quite optimal following surgery, an insole will be sufficient treatment in most cases.  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 saphenous nerves.  They supply sensation to the side and the top of the foot and toes.  They may rarely become damaged during the surgery and this might 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 <5% chance of this happening.

CRPS – This stands for complex regional pain syndrome. It occurs rarely (1%) in a severe form and is not properly understood. It is thought to be inflammation of the nerves in the foot and it can also follow an injury. We do not know why it occurs. It causes swelling, sensitivity of the skin, stiffness and pain. It is treatable but in its more severe form can takes many months to recover.

Post-Operative Course: Ankle Arthrodesis

 Day 1

1.   Below knee cast (backslab plaster) applied at end of surgery

2.   Expect some numbness in foot for 12-24 hours

3.   Pain medication and elevation of foot

4.   Blood drainage through cast expected

 Day 2

1.   An xray may be obtained

2.   Elevation of leg as much as possible for first 2 weeks

3.   Mobilisation non-weight bearing with physiotherapist (crutches / frame)

4.   Discharge home day 2 usually possible with arthroscopic fusion

5.   Discharge home day 3 – 4 usual with open fusion technique

6.   No weight bearing on operated leg for first 6 weeks

 2 Weeks

1.   Outpatient review of wounds and removal stitches

2.   Application of new cast  / removable boot

3.   May shower / bath if wounds healed 

4.   Allowed to weight bear on operated leg when standing only 

5.   No weight bearing on operated leg when walking for 6 weeks

6.   May return to driving at this stage ONLY IF left leg surgery only and automatic vehicle – otherwise unable to drive until 3 months post surgery

6 Weeks

1.  Outpatient review and partial weight bear in removable boot (~50% body weight)

2. Increase weight bearing to full body weight at 10 weeks from surgery

3.   To remain in boot until 3 months following surgery

4.   Using crutches / frame until 3 months post surgery

 12 weeks (3 months)

1.   Outpatient review with xray on arrival

2.   Usually the boot can be removed at this stage if xrays satisfactory

3.   Begin physiotherapy and rehabilitation program

4.   Gradually increase activity level as symptoms dictate

5.   May return to driving at this stage

Sick Leave

In general 4 weeks off work is required for sedentary employment, 12 weeks for standing or walking work.  We will provide a sick certificate for the first 2 weeks; further certificates can be obtained from your GP.

Driving

May return to driving after outpatient review at  2 weeks post surgery ONLY IF left leg surgery only and automatic vehicle – otherwise unable to drive until 3 months post surgery.

These notes are intended as a guide and some of the details may vary according to your individual surgery or because of special instructions from your surgeon.