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Cavovarus Foot

 - See: Pes Cavus:

- Discussion:
- seldom present at birth, the deformity gradually becomes apparent as childs foot grows and matures;
- components:
- heightened longitudinal arch - cavus -
- plantar flexion of 1st ray and pronation of the forefoot
- responsible for cavus appearance of foot;
- on wt bearing it forces heel into varus position causing wt to be born onto lateral border of foot;
- hindfoot varus: variable degree of hindfoot varus;
- pronation & adduction of forefoot;
- clawing of toes;
- long toe extensors become accessory dorsiflexors of the foot w/ resultant clawing of the toes;

- Diff Dx:  2/3 of these patients will have a neurological disorder
- charcot marie tooth: (anterior tibial muscle  weakness is characteristic of CMT);
- references:
- Prevalence of Charcot-Marie-Tooth disease in patients who have bilateral cavovarus feet.
- Correction of cavovarus foot deformity in Charcot-Marie-Tooth disease.
- paralytic muscle imbalance
- congenital clubfoot: residual deformity;
- idiopathic;
- spinocerebellar degeneration
- spinal dysraphism
- spinal cord tumor:
- polio
- cerebral palsy
- occult hydrocephalus
- peripheral neuropathy;
- becker muscular dystrophy
- peroneal nerve injury

- Exam:
    - flexibility of hindfoot is evaluated using Coleman Block Test;

- Radiographic Features:
- wt bearing radiograph:
- metatarsals are excessively plantar flexed;
- midfoot is elevated;
- hindfoot is in varus position - reduced plantar flexion of the talus;
- dorsiflexion of the MP joints is also apparent;

- Work Up:
    - in previously normal foot in which neurological problem is considered, EMG should be done;
- radiograph of lumbo-sacral spine taken;
- MRI of spinal cord (to r/o spinal cord tumor or dysraphic lesions),
- CT scan of the brain for evaluation of occult hydrocephalus;

- Treatment Options for Cavovarus Foot:
- surgical treatment of the cavovarus foot is based on rigidity of foot;
- tendon lengthenings and transfers are used for flexible feet, and bony procedures are added for fixed deformities;
- plantar fascia release;
- younger children can be treated w/ radical plantar release, followed by sequential manipulations and cast applications;
- even w/ flexible hindfoot, soft tissue release must usually accompanied by osteotomy of either the first metatarsal of medial cuneiform;
- first metatarsal osteototmy;
- dorsal closing wedge osteotomy of the first metatarsal base (or first cuneiform) is combined with radical plantar release;
- tendon transfers
- indicated for deformities due to neurologic disorder w/ muscle imbalance;
- long toe extensors are moved to metarsals (Jones technique) or to tarsals (Hibbs technique);
- also consider transfer of posterior lateral tendons to dorsolateral aspect of foot;
- in older children and adolescents, simple soft tissue releases are usually inadequate because adaptive bony changes have occurred;
- calcaneal osteotomy:
- indicated if lateral block test shows an abnormality;
- triple arthrodesis:
- reserved for rigid deformities in patients at maturity;
- in rare instances triple arthrodesis must be coupled with an osteotomy of the forefoot;
- claw toes:
- claw toe deformity is approached after cavovarus foot correction;
- in the report by Sammarco GJ, et al (2001), the authors report on 21 feet in 15 patients who underwent osteotomies
of the calcaneus and one or more metatarsals for symptomatic cavovarus foot deformity;
- etiologies included hereditary motor sensory neuropathy (HMSN) (15 feet), post-polio syndrome (two feet), sacral cord lipomeningocele (2 feet),
parietal lobe porencephalic cyst (1 foot), and idiopathic peripheral neuropathy (1 foot);
- presenting complaints were metatarsalgia (15 feet), ankle instablility (5), and ulceration beneath the 2nd metatarsal head (1 foot);
- Maryland Foot Rating Score (University of Maryland) improved from 72.1 (avg.) preoperatively to 89.9 (avg.) post-op (follow-up 70.9 months avg.).
- AOFAS Ankle-Hindfoot Score improved from 46.3 (avg.) pre-operatively to 89.1 (avg.) post-operatively, and the AOFAS Midfoot Score
improved from 40.9 (avg.) pre-operatively to 88.8 (avg.) post-operatively (follow-up 20.8 months avg.);
- postop AOFAS Ankle-Hindfoot Score for all 19 feet was 90.8 (avg.) and the post-operative AOFAS Midfoot Score for all 19 feet was 90.2 (avg.);
- ankle, hindfoot, and midfoot motion was maintained or improved in sixteen feet.
- complications included delayed union in two and nonunion in three of 66 metatarsal osteotomies;
- radiographic analysis revealed a decrease in forefoot adduction (9.6 degrees avg.) and a reduction in both hindfoot (9.1 degrees avg.)
and forefoot cavus (10.6 degrees) leading to an overall 13 percent reduction in the height of the longitudinal arch;
- ref: Cavovarus foot treated with combined calcaneus and metatarsal osteotomies.

Pes cavovarus. Review of a surgical approach using selective soft-tissue procedures.

Plantar release in the correction of deformities of the foot in childhood.

Pes cavovarus as a late consequence of peroneus longus tendon laceration.

"Idiopathic" pes cavus--an investigation into its aetiology.

Action of the subtalar and ankle joint complex during stance phase of walking.

A simple test for hindfoot flexibility in the cavovarus foot.

Hindfoot instability in cavovarus deformity: static and dynamic balancing.

Plantar opening-wedge osteotomy of cuneiform bones combined with selective plantar release and dwyer osteotomy for pes cavovarus in children.

The cavovarus/supinated foot deformity and external tibial torsion: the role of the posterior tibial tendon.

Tibial compartment syndrome and the cavovarus foot.

Adult cavovarus foot.