Calcaneo Cavus

Definition

 

Pure Cavus Deformity characterised by 

- dorsiflexion of Calcaneus 

- plantarflexion of Forefoot

 

Aetiology

 

Weakness of Tendoachilles

 

Usually neuromuscular

- Polio (Most common worldwide) 

- Spina bifida

- CP (can be due to overcorrection of T Ach)

- Spinocerebellar Degen (Friedreich's Ataxia)

- CMT

- Spinal dysraphism

 

Compartment Syndrome Deep Posterior 

 

Pathology

 

Imbalance of tendoachilles 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

- result is elevated longitudinal arch 

 

History

 

Difficulty walking 

Obvious deformity 

Shoe fitting & wear problems 

Painful callosities

 

Examination

 

Elevated longitudinal arch 

 

Prominent heel with abundant callus on plantar aspect 

- called pistol grip deformity 

 

Heel usually in neutral

 

Usually claw toes 

 

Xray

 

Lateral xray

- calcaneal pitch > 30o

- Meary's angle > 30o

 

MRI 

 

Exclude dysraphism

 

Management

 

Non-operative

 

Modification of shoe wear & orthoses required 

- cannot control deformity alone

- doesn't work

 

Operative

 

Age 0 - 5

 

Best avoided

 

Tendon transfer

- T Ant to T Achilles

 

Age 5-12

 

Grice arthrodesis STJ 

- extra-articular

- stabilise STJ

 

Transfer muscles

- must be > Grade 5 power

 

Options

- Tibialis anterior

- Tibialis posterior

- peroneals

 

Age >12

 

As Above

 

Triple arthrodesis