pathology: hollow foot

yogabook / pathologie / hollow foot

hollow foot (pes cavus, pes excavatus, pes cavovarus)

Definition of

Sometimes congenital, familial, but mostly acquired deformity of the foot with a raised longitudinal arch (also: plantarflexed metatarsus, especially Os metatarsale 1) and supinated(varus) calcaneus(hindfoot varus), more ventral bones are pronated(valgus). About 10% of the population have a more or less pronounced hollow foot.
Three types can be distinguished according to aetiology:

  1. Paralytic hollow foot: neurogenic
  2. Residual hollow foot after congenital clubfoot
  3. idiopathic hollow foot

For adequate therapy, the cause must be clarified with appropriate diagnostics.
Congenital (genetically determined muscle imbalance) or acquired depending on the load (heel or bunion):

  1. High-arched foot: slightly raised instep, hardly pathogenic, rather a normal variant
  2. Bunion hollow foot: especially steep 1st ray, a lot of weight on the metatarsophalangeal joint when walking, splayfoot tendencyand claw toe formation
  3. Heel hock: particularly steep calcaneus, reduced weight on the balls of the feet and toes, dystrophic calf muscles

The hollow foot usually has less cushioning, therefore poorer pressure distribution and an increased tendency to calluses, calluses and painful pressure points, as well as an altered gait pattern. There is usually a varus position of the calcaneus(hindfoot varus) and neighboring bones, sometimes resulting in overload-related ligament damage in the outer foot. The varus position of the calcaneus also leads to a tendency to ankle arthrosis in the joint between the talus and tibia via the overlying talus, as the two bones no longer articulate fully. This results in limited flexibility of the ankle joint and a tendency to impingement on the ventral caudal tibia, which can lead to osteoarthritis. A splayfoot with pressure points and corns often develops as a result of the forefoot strain, and claw toes (claw toes) and metatarsalgia frequently develop, usually due to intermetatarsal bursitis. The relatively rigid foot and the altered gait pattern usually result in weakness of the foot muscles and the fibularis muscles(fibularis brevis and fibularis longus) or their tendons, which can become chronically inflamed, but also lead to additional instability of the OSG (in addition to the angular deformity), as well as a tendency to plantar fasciitis, as the plantar fascia is too tight. The 20% idiopathic cases are usually mild and non-progressive. To a certain extent, the hollow foot is the opposite of the flat/flexed foot.

ICD Q66.7

Cause

  1. congenital, familial disposition
  2. neurogenic: Nerve damage to the foot muscles
  3. Paralysis: Polyneuritis, polymyelitis epidemica; consequences of spina bifida at birth
  4. traumatic: bone and joint damage, especially to the talus or calcaneus
  5. Secondary in muscle diseases, then often as the first sign

Predisposing

  1. unsteady gait
  2. Tendency to unkink(supination trauma)
  3. Disruption of the system of the tibialis anterior and fibularis longus that stabilizes the longitudinal arch of the foot
  4. Hallux valgus plus hindfoot varus (with or without bow leg)

Diagnosis

  1. Angle between the axis of the talus and the os metatarsale I 20-40 instead of 0°
  2. Inner longitudinal arch of the foot raised by at least two cm, in rare cases also raised outer edge
  3. X-ray (bone position), MRI (soft tissue, bone edema), neurological examination (innervation disorders: ENG or EMG). X-ray of the lumbosacral spine.
  4. If neurogenic causes are suspected, also myelography

Symptoms

  1. Pressure points on the instep, ball of the foot and toes, especially plantar under the metatarsophalangeal joints, possibly painful
  2. contracted plantar fascia, often plantar fasciitis, tendency to heel spurs, increased tendon tension, tendency to cramp, reduced longitudinal flexibility of the foot
  3. Hallux valgus
  4. Splayfoot
  5. Claw toes
  6. Hammer toes
  7. Varusposition/supination of the calcaneus(hindfoot varus)
  8. Transfer metatarsalgia
  9. Heel pain, Haglund heel
  10. Weakness of the foot muscles
  11. Pain on exertion, especially under the head of the 1st and 5th os metatarsale, possibly also diffuse in the tarsal area
  12. Apparently „too short“ foot
  13. Altered gait pattern, unsteady gait, pain when walking
  14. Lateral wear pattern of the shoes
  15. Usually mild symptoms at a young age, presentation to a doctor is usually due to associated foot or heel pain
  16. Possible rotational misalignment in the OSG, supination trauma exacerbates this
  17. Tingling on the instep (in shoes)

Complications

  1. Repeated supination trauma
  2. Falls
  3. Irritation of the Achilles tendon(Achillodynia), anterior (retromalleolar or retrocalcaneal) bursitis and Haglund’s heel due to increased pressure from the shoe
  4. Sprains
  5. Formation of a splayfoot with claw toes
  6. Fatigue fractures of foot bones, especially laterally
  7. Consequential muscular imbalances andjoint damage further proximally, e.g. back pain and disc damage with one-sided hollow foot

Therapy

  1. Therapy of the causes
  2. Inlays
  3. PT
  4. orthopaedic shoes
  5. Surgery if necessary (osteotomy, transfer of tendons, intervention on the plantar fascia). If necessary: Arthrodesis
  6. Prophylaxis: walking barefoot on natural, soft surfaces; avoid tight shoes and high heels

Asana practice and movement therapy

The acquired hollow foot is often associated with a compensatory overstretching of the toe extensors, in which case it is necessary to stretch these extrinsic muscles with corresponding postures such as hip opener 5 or baddha padasana. This applies all the more if claw toes or claw toes have already developed. If there is a varus position of the calcaneus, the fibularis group must be checked for weakness and trained, whereby a distinction must be made between the fibularis longus and the other muscles of the fibularis group, see below. Particularly suitable for this are all standing postures with a balancing character in which the lateral part of the rein system of the ankle joint must be used to press the metatarsophalangeal joint area to the floor, e.g. in parivrtta trikonasana. A special case is the fibularis longus with its attachment tendon pulling medially over the sole of the foot, which can pull the forefoot too strongly towards the plantar side in hypertonicity if the tibialis anterior does not provide adequate counterforce. Exercises to harmonize the ankle ’s ligament system are indicated here, as in other cases, especially those with the pelvis turned towards one foot pointing forwards, such as in parivrtta trikonasana.

The tension of the active and passive tensile straps of the longitudinal arch of the foot must be reduced so that the cavity of the foot and the overloading of the forefoot can be reduced. Stretches with a fascia roll used transversely to the longitudinal direction of the foot are suitable for this, as are postures with the toes bent upwards on the wall and the sole of the foot resting on the floor, which stretch the longitudinal intrinsic toe flexors.

Irritation of the Achilles tendon ( Achillodynia), local bursitis and the presence of a Haglund heel must also be checked and therapeutic intervention provided if necessary. In principle, the function of the outer ligaments of the ankle should also be checked and, if necessary, treated with insoles. The steep position of the calcaneus(distal to the dorsal side of the foot) can also lead to bony impingement in the ankle joint with a tendency to ankle arthrosis. This tendency may also be due to the fact that the varus position of the calcaneus tilts the talus, which places unequal stress on the joint surfaces in the ankle joint, i.e. medial overloading. The high tension on the plantar fascia in hollow feet can also lead to plantar fasciitis, which requires stretching in the same way as the hollow foot itself.

The chronically overloaded forefoot must also be checked to see whether a splayfoot or even a hallux valgus has already developed. In addition, the patient’s history must be checked to determine whether the varus position of the calcaneus has caused supination trauma and, if so, the condition of the lateral ligamentous apparatus. Possible torsions in the OSG due to varus malalignment of the calcaneus can also lead to rotation of the foot in relation to the tibia and altered gait. Finally, the lateral knee joint must be checked for meniscus damage that may have been caused by the varus malposition of the calcaneus.

In the asanas, care must be taken to counteract an existing varus position of the calcaneus as much as possible. The fibularis group can help here, but also the adductors, which try to push the feet towards each other in standing postures with parallel feet such as tadasana and prasarita padottanasana. This creates a counterforce (or valgus moment) in the subtalar joint.