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Sinus Tarsi Implant for flexible flatfeet

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  • Sinus Tarsi Implant

  • Gastrocnemius Lengthening

What are flexible flatfeet?

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Flexible flatfeet are feet that appear flat when the patient stands but when the patient stands on tip toe the arch reforms. Flexible flat feet appear in children from a young age and may disappear after the age of 7-10 for many children. We know that in individuals who have lifelong flat feet that they are more susceptible to failure of the structures which support the arch. If individuals develop warning signs that the arch of the foot is failing it may be that surgery to protect the structures which support the arch of the foot is advisable.

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What is the Tibialis Posterior Tendon?

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The Tibialis Posterior is a muscle that runs deep in the calf and its tendon inserts onto the arch of the foot. The tendon is one of the key arch supports along with several ligaments (and also the bones whose shape forms the arch of the foot).

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When the tibialis posterior tendon fails the arch collapses and the entire foot changes shape. Pain is often the most common reason for an individual to seek a specialist opinion but severe swelling can also occur in the period when the tendon ruptures.

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Patients without a normal arch find that their foot feels very inefficient. The failing arch continues to tear the damaged soft tissue which once held the arch in place. The tearing leads to episodes of pain and swelling in the medial ankle and foot.

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Sometimes there is some warning that the tendon is failing. It can help patients to have a sinus tarsi implant which can prevent the foot from moving into positions that cause the tendon to be injured.

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What is the Spring Ligament?

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The Spring Ligament supports the arch of the foot. It is deep inside the plantar foot under the tibialis posterior tendon. We know that in some individuals the Spring Ligament tears before the tibialis posterior tendon tears. When is tears it can resemble the rotator cuff tear that shoulder patients suffer from. Repair is possible but it is deep within the foot so healing is slow. The spring ligament is always repaired when a patient has a tibialis posterior tendon reconstruction but a sinus tarsi implant can help to support the arch of the foot and should stop further tearing in the spring ligament.

 

What are the treatment options when a patient has a painful flatfoot?

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When the tendons and ligaments which support the arch of the foot are inflammed or damaged but still working there are options:

  1. Insoles to elevate the arch and stiff soled shoes such as walking boots or even custom shoes.

  2. Release the tight muscle in the back of the legs to allow the arch supports to work better.

  3. In some special cases keyhole surgery on the tendon to take away painful inflammed tissue around the tendon.

  4. Key hole surgery to insert a sinus tarsi implant which will allow the spring ligament and tibialis posterior tendon a chance to rest and repair. Gastrocnemius lengthening is needed in combination with this surgery.

 

Why do the soft tissues heal so slowly?

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In relative terms surgery on bone heals very quickly and keyhole bony surgery heals even faster. By contrast surgery which requires tendons to heal is very slow. (Tendons are very specialised soft tissue made up largely of dense protein which is super-organised in order to give the tendon strength. Tendons have a poorer blood supply and only a small amount of cells within them. It is the cells which must make the proteins and because their are few cells, little blood supply of nutrients and a complex structure to heal; the end result is slow healing.)

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What is a Sinus tarsi Implant?

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A sinus tarsi implant is a small metal spacer which sits between the calcaneus and the talus. It holds these bones apart and prevents the arch from collapsing. The implant is also called an arthroereisis screw. The arthroereisis screw sits between the two bones in an area that does not have any cartilage, called the sinus tarsi. This is why the screw is called a sinus tarsi implant.

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How Long Should a Sinus Tarsi Implant Stay in For?

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There are no clear guidelines about how long the implant should stay in for. If the implant causes no pain there is no need to remove it but if there are any symptoms, it can be removed after 6 months. There are reports that the implant produces some positive changes to how some patients use their arch permanently. If the implant causes no symptoms and allows the patient to resume normal life - it is unlikely that the surgeon and patient will decide to remove it.

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What can I expect on the day of surgery?

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  • The surgery will normally be under a general anaesthetic.

  • Normally this is a day surgery case (unless the surgery is combined with a surgery to realign a bone which is a bigger surgery).

  • I will numb the ankle with local anaesthetic so that you will be comfortable when you wake.

  • There will be a big bandage on your ankle which you will keep clean and dry

  • You will be placed in a removable boot (such as the Aircast boot)

  • You will be given crutches and told to weight bear in the boot with the aid of crutches as needed

What are the risks and complications?

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The vast majority of patients do extremely well. A small group of patients need extra physio due to swelling or stiffness. Complications include infection, blood clots (DVT), nerve damage, painful screw requiring removal.

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There are extremely rare reports that the implant can lead to arthritis in the joint or to fracture of the bones around it.

When can I drive?

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The best guide that you are safe to return to driving is that you are able to walk well without crutches and without a plaster or a boot. The usual time scale also depends on whether you had surgery on your right or left foot and whether you drive a manual or an automatic

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  • Right side and all car types: 2-4 weeks

  • Left side and manual car: 2-4 weeks

  • Left side &automatic car: 2 weeks

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How long should I take off work?

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The time you require off from work depends on what type of job you do. The first two weeks of healing are critical and so you must have this time off work. Many people are able to work from home and so if you can avoid commuting in the first four weeks, you will find that your ankle does better. If your employer can be flexible with your activity at work you may be able to do some lighter duties or reduced hours from 2 weeks onward. If you work on your feet all day, do a manual job, or are required to wear dress shoes you may need 4-6 weeks before you are back at work.

Clear Advice About DVT

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A DVT is a Deep Vein Thrombosis or a blood clot in the leg. A blood clot occurs after surgery where patients are placed in a splint for about 1 in every 100 patients. You can help prevent a blood clot by keeping your knee and ankle moving. Keeping yourself hydrated is also helpful to prevent a DVT. Finally elevating your leg to the level of your heart will minimise the amount of swelling you have which will also help to prevent a DVT. You will be given Aspirin for the first two weeks when you at your least active.

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We will discuss how best to prevent a DVT and for most patients we opt to use Aspirin. If you have had a previous DVT we will opt to give you injections of  blood thinners for the first two weeks after surgery. After two weeks the risk is not completely gone however, you will be able to be more active. Most patients would rather stop blood thinners at that stage and monitor their leg for symptoms.

 

If you were to develop a DVT you would likely have some symptoms and so it is very helpful if know what to look for:

  • The leg (above the dressing/foot) would become hard, heavy, swollen, painful and/or red

  • If you were to have any of the above symptoms you would have to have a scan to look for a blood clot and then be treated with blood thinners

If the blood clot were to move to the lungs you would have a pulmonary embolism which is a medical emergency

  • The symptoms of a pulmonary embolism are breathless & chest pain- Call 911

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The Recovery After Sinus Tarsi Implantation and Gastrocnemius Lengthening

Instructions 0-2 weeks

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  1. Elevate Leg Above Heart most of the time

  2. Keep dry for two weeks

  3. Aspirin 75mg once a day

  4. Partial weight bearing in air cast boot with an arch support insole and crutches

  5. Move toes, ankle and knee

  6. No weight bearing in bare feet!

 

2 weeks in clinic

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  • I will arrange to have your plaster & sutures removed

  • You will then be referred for physiotherapy

  • You can weight bear fully in the aircast boot with your insole

  • Your physio will help you start to do range of motion exercises out of the boot

  • You will then be able to wash the ankle

  • You can remove the boot at night and when doing physiotherapy

 

4 weeks

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  • You can progress to full weight bearing in the aircast boot

  • It is essential that you have put your arch support insole into the aircast boot

  • Week on week you should find that you can put more weight through the boot

  • Eventually you will take your weight fully through the boot

 

6 weeks in clinic

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  • I will send you for a X-rays of the ankle and you will be able to weight bear out of the boot for these xrays

  • Provided the X-rays show some early healing you will be allowed to wean out of the Aircast boot

 

6 weeks- 3 months

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  • Discontinue boot

  • Work on developing strength in foot with physiotherapy - see the Surrey Stages Program Below

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 Physiotherapy instructions once able to weightbear and remove the Aircast boot

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  • Use the Boot for comfort

  • When your physio and surgeon OK you coming out of the boot you must not be bare foot

  • Instead use a shoe with your insoles

  • Gradually use the boot less and less as comfort allows

  • Use Contrast bathing with bowls of hot and cold water. Place foot for 20 sec in cold and then alternate for 30 sec in hot. Do for 5 min.

  • Your physiotherapist can use other local modalities to reduce swelling

  • You may ice the ankle if this helps

  • Use a compression stocking and elevate the ankle above the heart to help swelling

  • Start to work on strengthening

    • Theraband Resistance

    • Cycling on stationary cycle

    • Swimming and Hydrotherapy

    • Work on developing an even gait

    • Progressing to double heel rises

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THE ‘SURREY STAGES’ PHYSIOTHERAPY STRENGTHENING PROGRAM

 

BRONZE AWARD

DOUBLE HEEL RISES (DHR)

  • You can go up and down on tiptoes in sets of 3, slowly and 15 reps in each

  • You can stand on a skipping rope and adjust your foot position

  • You can hold a DHR for 15 seconds

  • It can be difficult to progress to the next award level because the ankle will take double the weight when you move to lifting the good leg to lower only on the operated leg.

  • You are better to stay at the bronze award level but to add in a back pack with increasing weight as you feel ready for more

  • When you have done this for some time you will be ready to progress to the silver award level

 

SILVER AWARD

DOUBLE HEEL RISES WITH A LIFT

  • May need to add weight in backpack on DHR to reach silver level

  • You go up on both feet but lift unoperated leg and lower slowly only on operated leg

  • 3 sets, working up to 15 reps in each

  • You can stand both feet on a wobble board

  • You can hold a solid DHR for 20 seconds

 

GOLD AWARD

SINGLE HEEL RISES

  • 3 sets, working up to 15 reps in each

  • You can stand on one foot on wobble board

  • You can hold a solid DHR for 40+ seconds

  • Many patients decide to finish physiotherapy when they have achieved this level

 

PLATINUM AWARD

  • Progress to hopping in all directions

  • Double Hops

  • Gentle jogging to reintroduce running

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