Flatfoot (also called pes planus) is a foot deformity characterised by the collapse of the arched shape of the foot and a deviation of the heel and the forefoot (valgus of the heel and abduction of the forefoot). It affects nearly 20% of the population in its asymptomatic form and remains a major reason for consulting a specialist.
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Flat foot symptoms and treatments
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Fig. 1
Normal foot
Talus, midfoot and forefoot aligned
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Fig. 2
Flatfoot
Note the flattening of the calcaneus, the plantar tipping of the talus and the misalignment of the foot bones.
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Fig. 3
Posterior view. Normal foot, aligned.
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Fig 4
Outwards deviation of the heel (calcaneal valgus)
It is important to distinguish between different forms of flatfeet:
- Flatfoot in children. Flatfeet in children are normal up to the age of six. This condition is due to muscle and ligament immaturity and corrects spontaneously with growth.
- Congenital flatfoot. Persistent form of flatfoot after childhood. It is usually asymptomatic and requires no specific treatment.
- Acquired (or adult) flatfoot. This is the pathological form of flatfeet. It develops in adulthood and usually causes pain, sometimes severe. This is typically the form that requires treatment and medical support.
The arch of the foot is maintained by a series of anatomical structures. The first of these is a bony structure that ensures the normal alignment in the shape of an arch. Ligament structures help maintain the position of these bones and overcome the crushing effect caused by the body’ weight pressing down on the foot. Finally, several ligaments and muscle structures are actively involved in the shape of the foot. The most important is the posterior tibial tendon, which attaches itself to the middle part of the foot and maintains the plantar arch and alignment of the heel. Any injury to this tendon will cause specific pain in the inner foot and a risk of painful flatfoot.
Clinical presentation
Acquired flatfoot is a common and often poorly tolerated condition. In the early phases, pain occurs at the insertion of the posterior tibial tendon.
Injury to the posterior tibial tendon (tendinopathy). Observe the position of the painful insertion, on the inner and lower part of the foot.
With the progression of the condition, the tendon will lose its efficacy and sometimes even tear. When this happens it can no longer support the foot and a flatfoot will develop, which quickly becomes painful. Moreover, the heel tips outward, the foot arch collapses and the forefoot deviates outwards.
When should you consult a specialist?
Flatfoot in infants is a common reason for consulting in paediatrics. Parents are usually reassured about the natural occurrence of this type of deformity.
However, the adult-acquired form causes pain and damage, which can be permanent, and a specialist should be consulted. In fact, untreated pathological flatfoot can cause severe deformities which can sometimes be very difficult to treat or may be irreversible.
The diagnosis is made by a specific clinical examination, radiological assessment and sometimes by an ultrasound or MRI. Triggering factors should be analysed such as weight gain, diabetes, history of trauma, anatomical malformations (coalitions, etc.), some drug treatments or incorrect footwear.
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Non-surgical treatment
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Surgical treatment
When conservative treatment with physiotherapy or orthotics is insufficient, surgery may be required. Any treatment will naturally relate to the cause in question.
As injury to the posterior tibial tendon is an inherent part of this condition, it will be systematically explored during surgery. Surgery will excise the most inflamed areas (synovectomy), repair any tendon tears and, in the most advanced cases, reconstruct the tendon by transferring another tendon located nearby (generally the flexor digitorum).
The outcome of the surgery will depend on the severity of the injury.
In flexible flatfoot and in mild to moderate conditions, the exploration of the posterior tibial tendon will be associated with a section of the heel bone, also called an osteotomy. This allows us to move the area that touches the ground and used as an attachment for the Achilles tendon. It is worth restating that in cases of flatfoot the heel deviates laterally. During the osteotomy, the rear of the heel is moved inwards to correct the axis of the hindfoot (= calcaneal varus osteotomy). All is maintained in position by a screw or bone clips.
Calcaneal osteotomy: the heel is cut and moved to restore the normal alignment of the hindfoot.
In general, this surgery is performed using a 6-cm incision on the lateral edge of the heel. Very recently, new techniques have emerged and we now perform this technique using a percutaneous minimally invasive method. This reduces the scar to 2 mm and limits the risk of injury to the surrounding soft tissues.
Finally, shortening the Achilles tendon is standard practice in flatfeet (gastrocnemius equinus); the surgery is completed by stretching the tendon in the calf either via open surgery or by endoscopy.
In rigid flatfoot cases, tendon transfer surgery and osteotomy is not enough, as a dynamic correction is required, which is dependent on the various joints working properly. Cases of severe rigid flatfoot require the blocking of the joint, which implies major surgery. Several of the joints affected will then by sacrificed by merging them into the correct position in the foot, to straighten the arch, reduce the deviation of the heel and restore the correct support to the foot. The fusion of the joints, also called an arthrodesis, results in significant changes to the axes and the rotation of the various parts of the foot (double or triple arthrodesis of the foot).
Other procedures can also be carried out during the surgery, depending on the overall clinical picture.
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Post-surgical follow up
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Risks and complications