The usual features associated with a pes cavus foot include:
- An overall shortening of foot length
- Elevated hind foot
- Downward deflected mid foot
- Inward bent forefoot
The high arch shape is either due to a tight or contracted plantar fascia (the tough sheet of fibrous tissue that runs along the sole of the foot) or due to a weakness in one muscle group causing unopposed action of the other, resulting in fixed plantar flexion of the foot.
Common causes include:
- Charcot Marie Tooth disease
- Cerebral palsy
- Spinal cord tumor
- Friedreich’s ataxia
- Malunion of heel or anklebone fractures
- A consequence of burns or compartment syndrome
In about 20% of cases, the cause is unknown and is referred to as idiopathic pes cavus; these cases are usually non-progressive.
Effects on foot physiology:
The high arch affects the normal mechanics of the foot, making it rigid and decreasing its shock-absorbing capability. The foot is less well balanced and does not distribute load as efficiently as a foot with a normal arch shape.
The usual complaints associated with pes cavus include:
- Pain on the lateral side of the foot
- Metatarsalgia (pain in the ball of the foot)
Plantar fasciitis (pain at the bottom of the heel)
Achilles tendonitis (pain at the back of the heel)
- Ankle arthritis (inflammation of the ankle joint)
- Callosities (thickening of the skin over painful areas)
- Problems with wearing shoes
- Stress fractures
- Knee and lower back pain
It is essential to diagnose the actual cause of the problem. The goal of treatment is to support the foot and improve its balance, as well as load distribution, thereby relieving pain and preventing further progress of the condition.
Insole devices are quite helpful in relieving the pain associated with pes cavus deformity.
- They increase the foot surface area contacting the ground, thus providing a greater area for load distribution. This prevents excessive loading of the heads of the metatarsal bones, reducing metatarsalgia and formation of callosities.
- A high-arched foot is usually accompanied by lateral ankle instability, and the foot usually rolls outwards excessively (over-supinates) during walking. insole devices not only help to check this excessive supination, but also prevent excessive pronation (inward rotation) of the foot during walking, providing better stability to the ankle.
Exercises to strengthen the weak muscles reduce muscle power imbalance. Chiropractic therapy also helps to improve the symptoms.
Surgery is indicated only when a conservative approach fails to solve the problem.
Surgical procedures include:
- Manipulation of ligaments and tendons, such as plantar fascia release, to decrease its contracture, Achilles tendon lengthening, etc.
- Osteotomy (bone cutting) of heel bone or metatarsal bones to improve alignment and flatten the arch
- Triple arthrodesis: artificial union of three joints in the ankle region to relieve pain and improve ankle stability
An early diagnosis helps to produce a better prognosis.