Flat Foot Correction 1: FDL Tendon Transfer

What will the surgery involve?

i. Anaesthetic – usually a general anaesthetic is required; as well as this, local anaesthetic will usually be placed around the knee close to the nerves that provide the sensation to your ankle and foot (popliteal nerve block). This will mean that the foot and ankle are likely to be numb when you wake after the surgery- this lack of sensation usually lasts between 12 and 24 hours. You will have a chance to discuss your anaesthetic with the anaesthetist before the operation.

ii. Incisions
 – one longitudinal incision is made on the inside of the foot
a further incision is made on the side of the heel bone (os calcis)
a further small incision is usually made at the back of the heel screw
incision(s) may be required over the calf muscle if it is tight and needs lengthening
other incisions may be required if additional procedures are performed

iii. The surgery – The abnormal tendon (tibialis posterior) is inspected and the abnormal area (usually the whole tendon) is removed. The flexor digitorum longus (FDL) tendon* that passes down to the second to fifth toes is then identified and transferred to the navicular bone, where the tibialis posterior tendon normally inserts, to replace it. It is secured here through a hole made in the navicular, either by stitching it back on to itself or using a special type of screw (interference) or anchor. The heel bone is then cut and either the back of the bone shifted medially (towards the inside) or the outside of the bone lengthened by inserting bone from your pelvis (lateral column lengthening).

The calf muscle is then assessed for tightness, as will the shape of the rest of the foot and further procedures then performed as required.

* The FDL tendon can be used to replace the tibialis posterior tendon, as there is a link further down in the foot connecting it to the tendon that bends the big toe (FHL), so that even after then FDL tendon has transferred you will still be able to bend all of your toes.

iv. Stitches – Removable, non-dissolving sutures will be used to close the skin. These will be removed at your appointment about two weeks after surgery.

v. Dressings – Special dressings will be placed on the ankle and a plaster backslab will be applied, these should all be left in place until you are reviewed in the clinic at two weeks following the operation.

The plaster should be kept dry, applying a waterproof cover when showering is useful, the most commonly used can be found at www.limboproducts.co.uk

What happens after the surgery?

i. Going home – This is usually the morning following surgery depending on how easy you find using the crutches and your home situation (i.e. how many stairs you have).

ii. Pain relief – The local anaesthetic ankle should provide some pain relief, but you will be supplied with pain relieving tablets by the hospital (usually co-codamol or paracetamol and tramadol) these should be taken regularly initially. You can gradually reduce these after a couple of days as your pain allows. You should avoid non steroidal anti-inflammatory tablets eg. nurofen as these could stop the heel bone joining.

You will find it more comfortable to keep your foot elevated, if possible above the level of your heart, as much as you can for the first two weeks after surgery. This will help reduce the swelling and therefore also help wound healing.

iii. Walking – The amount of weight you will be able to apply through the foot/ ankle is as follows:
Weeks 0-6 No weight
Weeks 6-12 Gradual increase to full weight bearing in removable boot. You will be referred to a physiotherapist to start a series of exercises during this time

iv. Follow up – Your dressings and plaster will be removed at your outpatient appointment about two weeks after surgery. The sutures will be removed and you will be fitted with a new plaster

You will then be seen six weeks after surgery, when the plaster will be changed to a pneumatic walking boot.

You will be seen twelve weeks after surgery when an X-Ray will be taken and if satisfactory then you will be able to remove the boot.

v. Driving – If you the surgery is on your left ankle and you have an automatic car you may be able to drive two weeks after surgery, but you should check with your insurance company first.

If the surgery is on your right ankle you will not be able to drive until you can walk without crutches (or boot/ plaster) confidently. At this point you should check that you can place your foot on the pedal with sufficient force to do an emergency stop without pain, this should be tried in a stationary car; if you are able to do this you should then contact your insurance company to ensure that they will provide cover for you.

vi. Return to work – Approximately:
Office job – 6 weeks
Mobile job requiring driving – 12-14 weeks
Manual labour – 4-5 months

What are the risks of the operation?

There are a small number of risks of surgery including infection, nerve damage, blood clots, ongoing pain and the need for further surgery (please see General Risks of Foot and Ankle Surgery for further information)