Calcaneocavus

Definition

 

Deformity characterised by 

- dorsiflexion of calcaneus 

- plantarflexion of forefoot / plantaris / forefoot equinus

 

Both sides of foot have elevated arch

 

Aetiology

 

Weakness of triceps surae 

- polio - most common worldwide

- spina bifida

 

Polio LegPolio Leg

 

CP 

Spinocerebellar degeneration / Friedreich's Ataxia

CMT

Spinal dysraphism

Compartment Syndrome / Deep Posterior 

 

Pathology

 

Imbalance of T achilles and dorsiflexors

- dorsiflexion of calcaneus

- moves insertions of T achilles anterior

- further weakens the lever arm

 

Forefoot becomes flexed because of

- gravity 

- action of muscles during gait

 

Symptoms

 

Difficulty walking 

Obvious deformity 

Shoe fitting & wear problems 

Painful callosities

 

Signs

 

Elevated longitudinal arch 

 

Prominent heel with abundant callus on plantar aspect 

- called pistol grip deformity 

- usually claw toes 

 

Heel usually in neutral

 

X-ray

 

Lateral XR Foot 

 

1.  Calcaneal pitch > 30o

- dorsiflexion of calcaneus  

- < 20o normal

 

2.  Meary's angle > 10o

- talus - first metatarsal

 

MRI Spine

 

Exclude Spinal dysraphism

 

Management

 

Non-operative

 

Modification of shoe wear / orthoses

 

Operative

 

Principles

 

1. Correct deformity by soft tissue releases & osteotomy

2. Tendon transfer to calcaneus

 

Age 0-5

 

Indication

- spina bifida

- other conditions cause little disability

- don't operate

 

Operations

 

1.  T Achilles to fibula 

- prevents varus & stimulates fibula growth

 

2.  T Anterior to T Achilles

 

Age 5-12

 

Grice arthrodesis STJ + T Achilles transfer to fibula

 

Age > 12

 

Triple arthrodesis