Is the claw foot always considered a disease?

What it is and how it works

The foot has a complex skeletal structure, composed of 26 bones that work together thus enabling us to stand up, walk and run.
When walking, the foot goes from an arched position to positions where it is flat.
The Gait analysis (the study of motion patterns) allows us to analyze three different cycles: loading response, swing phase and suspension (when the foot is suspended).

Imagine your foot is a spring. When the foot is loaded, it has the functional advantage of being flat because it has to act like a cushion. On the contrary, when swinging the foot acts as a rigid lever and so has the advantage of being arched.

A high-arched foot, therefore, does not perform well when cushioning, and results more functional in the swing phase rather than in the load phase especially at a normal pace. When running, however, the movement resembles a sequence of jumps so the foot is almost constantly kept in supination.
This explains why sports that require agility, rapid changes in direction and speed best suit athletes with a claw-foot. Tennis champion, Nadal, whose ‘fast feet’ have made his success, could have nothing but high-arched feet!

On the other hand, sportsmen with high-arched feet who practice sports such as marathons or other activities in which feet are put under mechanical strain for long periods of time (such as military troopers), are more subject to fractures of the fifth metatarsus due to their foot’s reduced capacity of cushioning.

If a patient has suffered from an ankle or foot injury such as can be an ankle sprain, the best advice is to walk on regular surfaces in order to re-educate the foot to act as if it were a spring. When the patient is recovering but walking still proves painful, water will be the best choice. The exercise will no longer consist in walking along the beach but in ankle-high water.

The Pathology

A Pes Cavus turns into pathology when its characteristics are hyper-expressed. There are no rigidly defined limits, but rather precise pathologies and causes that may be of skeletal, neurological or post-traumatic nature.

When the skeleton is not correctly programmed

Flat-foot or cavus foot genes do not exist, but rather common development patterns (a sort of construction project of our body) on which external corrective stimuli do not have efficient and stable effects in time.
Due to different structures being involved, the symptomatic onset may vary considerably, which is why it could be difficult to trace it back to a pathological high-arched foot.
Patients may list symptoms similar to hyperkeratosis (or callus) beneath the first metatarsus, deformed claw-shaped toes and hallux (more evident in neurological feet), lateral back-foot pain, internal ankle pain or even feelings of instability, repeated ankle distortions and sprains.
The overall scheme posed by these symptoms is tied to the numerous anatomic structures that a high-arched foot brings with it. First of all, the forefoot is excessively stimulated during the loading phase and this may induce a metatarsalgia at the first metatarsal level. A callus is nothing more than the organism’s primary defence against improper strains.
The main problems occur at the back-foot and ankle level, where deformities are a synonym of loading alterations with consequent risks of instability (peritalar instability).
Patients frequently refer numerous ankle distortions characterized by ankle inversion and the feeling of constant instability. An MRI (Magnetic Resonance Imaging) may verify the presence of ankle ligament lesions (Anterior Tibia-Fibular Ligament, Calcaneo-Fibular Ligament, Posterior Tibio-Fibular Ligament), however it is vital that the patient understands that his/her instability is caused by the shape of the foot: it is highly-arched.
As a matter of fact, a frequent cause for ankle ligament reconstruction surgery gone bad is inextricably tied to a missing cavus foot diagnosis. In these cases, instability may be solved correcting the foot shape and not intervening on the ligaments, which is fundamental to prevent ankle arthrosis.

American author, Manoli, divides the claw foot into two distinct nosological families: “forefoot-driven” (determined by the front foot) and “hindfoot-driven” (determined by the back foot).
The forefoot-driven cavus foot is associated with a plantarflexion of the first metatarsus. This condition produces an adaptation of the hind-foot during supination (three-plane motion), resulting in a highly-arched foot.
A very simple test can help with the diagnosis (Coleman Block Test). The patient is asked to stand in front of us while a wooden block of about 1 cm in height is placed beneath the toe. If the hind-foot goes back to its natural position (not arched anymore), we are facing a “fore-foot driven” deformity which is only determined by the forefoot and viceversa should the correction not be visible.
This apparently simple difference is difficult to spot but actually conditions every therapeutic choice that follows.

The patient with a forefoot-determined claw foot may benefit from custom-made orthopedic insoles designed with a cut-off at the first metatarsal level (a depression at plantar level). Rarely is this conservative approach unsatisfying. In some cases, however, an osteotomy (bone correction) of the first metatarsal is a must, and can be carried out today with minimally invasive surgery and a fast recovery.

A patient with a hind-foot claw foot is unlikely to benefit from a conservative approach on the long run. These patients are usually listed for an osteotomy to reconstruct the deformities in order to bring the foot back to a natural shape, while optimal functioning is restored by means of surgery concerning muscles and tendons (tendon transfers).

When the peripheral nervous system is to blame

The foot is like a puppet mastered by muscles and tendons that, in turn, are governed by nerves. Lower limb peripheral nerve dysfunctions may therefore induce foot and ankle deformities and dysfunctions. In this case, problems may be either congenital or acquired.
In the first case, the main group of diseases is generated by the Charcot-Marie-Tooth 1 – 2 Syndrome (CMT 1-2), that is, hereditary neurological pathologies (regardless of gender), together with the rarer forms such as CMT-4 (autosomal recessive transmission) and CMT X (X-linked dominant transmission).
These diseases induce progressive axonal demyelination, so the stimuli the nerve sends along becomes progressively slower and inefficient.
The consequence is an initial inefficiency of intrinsic foot muscles (the ones that originate and connect within the foot) that then induces premature, claw-shaped deformity of toes and hallux. The latter is usually observed in high-arched feet and is more evident in neurologic pathologies.
Following the intrinsic muscles’ inefficiency, a front tibial muscle and peroneal inefficiency tend to occur inducing a common trait in the patient’s pace, who is obliged to lift the knee more than usual to avoid stumbling upon his/her own foot during the mid-moment between the foot on the ground and off the ground (oscillating phase).
For these patients, orthotic support may prove precious to enable a more comfortable step. However orthotics and orthopedic insoles cannot correct the deformities nor stop their progression.
Current surgery offers a valid solution for patients whose pathology has already lead to serious deformities as well as for those who have not yet incurred in it.
Skeletal surgical procedures on tendon transpositions may bring stability to the patient’s foot, guaranteeing a valid support to restore a physiological pace.
The diagnosis is neurological, however the orthopedic surgeon and the neurologist must work as a multidisciplinary team in order to carry out the best therapeutic plan to establish the surgery and its timing.

Acquired neurological pathologies are also an issue, and in the case of feet and ankles they are frequently caused by damage to single nerves or groups of nerves following central/peripheral ischemic pathologies, direct damage (traumas) or iatrogenesis. Once again, the neurologist and orthopedic expert should work on the diagnosis and the therapeutic plan together. In these cases, orthopedic braces may be of great help, aiding the patient in regaining a normal pace. At times, however, a tendon transfer surgery may be the best solution to enable the patient to achieve active control on motion without having to depend on orthopedic braces.

When traumas and fractures turn into ankle and subtalar arthrosis

The ankle and the back-foot are congruent anatomical structures with an intrinsic stability, meaning their anatomy makes it almost impossible to be subject to arthrosis. Arthrosis is the deterioration that affects articulations such as the back, the hip or the knee with ageing.
In some cases though, a trauma may change the design of a tibia, fibula, astragal and heel bone forever making them fracture-prone. An acute treatment intends to restore anatomical integrity even though it is rarely possible to restore the harmed part to a pre-trauma situation.

Patients who have suffered traumas of this kind may endure a post-traumatic claw foot, reporting reduced articulatory motion and a sense of asymmetry that tends to be confirmed by an uneven shoe consumption, or a feeling of constant pain both when walking and when at rest. These patients can be said to be affected by ankle arthrosis.
A Canadian author (S. Raikin) compared the impact of ankle arthrosis on his patients’ life quality; unsurprisingly ankle arthrosis has a negative effect similar only to that of the hip and greater than knee arthrosis.
Luckily, today there are many reliable solutions for the ankle but their application is dependent from the notion that in 80% of the cases, ankle arthrosis is of post-traumatic origin and therefore associated to a deformity. In most cases, be it the knee or the ankle, such deformity is manifested as a varus deformity.

Traumas and fractures involving the ankle (peroneal malleolus, tibia and astragal) or the heel, may leave us with a claw foot and a post-traumatic varus ankle. If left to their natural progression, these cases induce a progressive worsening of the deformity and function.
An early diagnosis of post-traumatic arthrosis allows the planning of a reconstructive surgery. The surgeon will adopt osteotomy techniques to correct the deformities (skeletal corrections), and the patient will go back to having realigned articulations without having to feel pain at every step.
A late diagnosis of post-traumatic arthrosis or serious articular damage still allow the recovery of ankle movements though a combination of osteotomy techniques and ankle prosthesis implants, thus giving the chance of putting the ankle and back-foot on axis without having to give up motion.