A flat or low arched foot is not considered abnormal and the height of the arch does not have any bearing on how well a foot can function. A foot that rolls in excessively with most of the weight passing over the inside border may be a cause for concern.
Surgical treatment is required in the severe cases when the poor alignment of the foot causes pain or fatigue or has a high chance of doing so. These patients are considered to have a pathological flat foot. The majority of these cases respond well to a combination of muscle stretching exercises, orthoses (shoe inserts), braces and supportive footwear. If the patient doesn’t respond to conservative treatment, then surgery might be considered.
Cases of a pathological flat foot
The foot is poorly aligned when a person is standing but when sitting with the weight off the foot the deformity usually corrects itself. It can be manipulated into a better position by hand.
The foot remains in a poor position whether the person is weight bearing standing or not. It cannot be manipulated into a straight position by hand.
The diagnosis is made following an examination of the foot. In certain cases, further investigations may be required such as X-ray, ultrasound, MRI or CT.
The vast majority of patients find that they can control their symptoms with the use of non-surgical treatments. Footwear is a key factor. The correct size, width and depth of shoe are key with adequate support to hold the foot in position (laced up). You will be advised on the best shoe for your problem. Flexible footwear is to be avoided. If inadequate shoes are worn, the rest of the non-surgical treatments are unlikely to be effective over the longer term.
Often, a combination of the following options are used:
Surgery to correct a flatfoot can be complex and is not necessary in the majority of cases. It is only considered when a person experiences severe pain that does not improve with conservative care and occasionally in children where the deformity is severe. Cases where the position of the foot is severely affected or where the joints are very flexible (hypermobile) may be more likely to require surgical correction.<
A combination of techniques and procedures is normally needed to restore a good position to the foot. The different types of surgery include osteotomies (cutting bones to re-align them), fusing joints, tendon lengthening and transfers as well as implanted devices to help maintain correction. The combination required for you will be determined by Podiatric Surgeon and will be discussed with you if you decide to proceed with surgery.
The majority of patients who undergo surgery to correct a flatfoot need to go through a long and challenging postoperative regime.
In most cases, the operation will involve several different procedures being performed at the same time with the aim of providing a well-positioned and functional foot. Listed below are some of the commonly performed procedures. Your podiatric surgeon will provide you with an opinion on which are suitable for you.
The operation normally lasts for about two hours and a cast is put on the leg after the surgery has finished. The cast will run from just below your knee to your toes. This reduces the likelihood of damage or movement at the surgery sites. X-rays of your foot will be taken during the surgery.
In many flat foot surgeries, we need additional bone to help with repositioning of joints or to fill in gaps between two bones. In these cases, we can take a graft of bone from the calcaneus (the heel bone). The calcaneus has a very good blood supply and so the ‘gap’ that is left in the bone fills in by itself. Calcaneal grafts can sometimes be used to improve the chance of healing between bones that we are trying to fuse.
A tight calf muscle will force your foot to roll inward. This can be prevented by lengthening the tendon just below the calf muscle (gastrocnemius). An incision of approximately 7 cm is made in centre of the back of your leg and the tendon is cut and lengthened. Lengthening of the tendon helps normal foot function but the calf is often weaker than the other side.
The tibialis posterior muscle is a powerful muscle that stops the foot rolling in too far. In some cases the attachment of the tendon is affected by an extra bone or the tendon may have stretched out affecting its function.
A condition called os naviculare is when an extra bone sits between the tibialis posterior tendon and the bone where it attaches in the arch of the foot (the navicular bone). The additional bone and the navicular bone can develop inflammation where they sit against one another. The additional bone can be removed and the tendon is then reattached to the navicular bone. The incision runs from around the inside of the ankle to the middle of your foot.
In cases where the tibialis posterior tendon has torn or become damaged, the foot will collapse inwards. In most cases the tendon is beyond repair. Another tendon that runs along side the tibialis posterior called flexor digitorum longus, can be used as a replacement. This tendon runs from the back of the leg into the toes and is used to curl the toes downward. It can be used without greatly affecting toe function as there is another tendon, which performs almost the same job within the foot. For this reason, it is often considered a ‘spare tendon’. Flexor digitorum longus is cut and attached under tension onto the navicular and replaces tibialis posterior. The incision runs from around the inside of the ankle to the middle of your foot.
This procedure is used to place the heel bone back in line with the lower leg. In cases where the foot excessively rolls inward, the heel bone can tilt out of position (see photo below). If this is the case then the heel bone is cut and moved back into an improved position. This helps provide greater stability and can improve the function of some of the muscles around the ankle in controlling the position of the foot.
The excessive rolling inward of the foot is reduced by placing a metal implant into the gap between the calcaneus and the talus called the sinus tarsi. When the foot rolls inward this gap reduces in size and expands when the foot rolls outward. By placing the right size implant into the sinus tarsi, the amount by which the foot can roll inward is reduced. This implant is normally well tolerated by the patient, but in certain cases it can cause irritation and needs to be removed. We have noticed that when the implant is removed, not all the correction is lost. This is considered to be an experimental procedure by the National Institute of Clinical Excellence although it has been performed for many years.
It is important to note that a sinus tarsi implant when used alone, does not work particularly well for the majority of flat feet needing surgery and as a result, it is normally performed with additional procedures.
This procedure lengthens the outside border of the foot in cases where the foot has become severely mal-aligned. There are a number of variations in the exact technique but effectively, a bone graft is inserted into the side of the heel bone or one of the joints on the side of your foot. Lengthening the outside border realigns the foot and increases the arch height. A screw or plate is normally used to help stabilise the bone graft.
In cases where the foot is rigid either because of arthritis or due to the abnormal formation of bones (tarsal coalition) then joining together of two or more bones in the foot might be considered. The aim of this is to stop excessive collapsing of the foot. Pain related to arthritis of the joints (when present) will be relieved and the foot would be repositioned to restore better alignment and stability.
Fusing joints solid is not always ideal but may be the only suitable option in patients who have severe deformity or are overweight.
The fusion might be of an individual joint as seen below with a talo navicular arthrodesis
Or of multiple joints with a triple fusion of three joints of the hindfoot.
These operations are normally carried out on a day care basis i.e. you would be admitted to the hospital on the day of your operation and will go home later the same day.