Cavus Foot

Most cavus feet have an underlying pathologic cause i.e. Not idiopathic
Consider
- CNS – CP, tumor
- Freidrich’s ataxia
- Cord – tether, lipoma, myelomengocele
- Nerve – CMT, post traumatic
- Muscle – posterior compartment syndrome
Last is idiopathic

History

Birth history, weight, milestones
Family History
Previous injuries
Previous foot surgery

Examination

Look at the neck & back
Look at the neurologic examination
Evidence of plantar fascia contracture
Coleman block test
Motion subtalar & midfoot

Investigations

Xray
- Plain films will show plantar flexion of the first metatarsal = talo – 1st metatarsal angle is normally 0 (Meary)
MRI
- Get MRI where indicated

Treatment

Nonoperative
- Transfer pain & metatarsalgia
- Accommodative orthotic
Operative
- Principles
  - soft tissue reconstruction in the face of bony deformity will stretch out
- Bony correction in growing child may recur, especially if soft tissue not balanced
  - Young & Flexible
    - Soft tissue procedure
    - Always a plantar release
    - May consider transferring the toe extensors to the metatarsal necks
  - Young with more rigid deformity
    - Plantar fasciotomy
    - Dorsal closing wedge osteotomy
    - If rigid varus closing wedge laterally – Dwyer
  - Older – rigid
    - Bony fusion & corrective osteotomy

CMT

Weak tib anterior & also dorsiflexors of the toes & peroneals
tendon transfer of choice is Tib posterior through the interosseous membrane

Polio

Calcaneocavus
Weak gastroc & tib post
Transfer the tib anterior posteriorly to the ankle plantar flexor