Below is an illustration of the varying degrees of heel position when view from behind relative to the ground. Inverted or varus heel is pictured to the left (A), neutral or perpindicular position is center (B), and everted or valgus heel to the right (C).
- Seldom present at birth, the deformity gradually becomes apparent as childs foot grows and matures;
- Heightened longitudinal arch - "Cavus".Plantarflexion of first ray and pronation of the forefoot.
- Responsible for cavus appearance of foot.
- On weightbearing 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 (CMT).
- Paralytic muscle imbalance.
- Congenital clubfoot: residual deformity.
- Spinocerebellar degeneration.
- Spinal cord conditions.
- Occult hydrocephalus.
- Peripheral neuropathy.
- Muscular dystrophy.
- Peroneal nerve injury.
- Flexibility of hindfoot is evaluated using Coleman Block Test.
- Weightbearing radiograph.
- Metatarsals are excessively plantarflexed.
- Midfoot is elevated.
- Hindfoot is in varus position - reduced plantarflexion of the talus.
- Dorsiflexion of the MP joints is also apparent.
- In previously normal foot in which neurological problem is considered, EMG should be done and possible evaluation of neck and/or brain;
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.
- PF release.
- Younger children can be treated w/ radical plantar release, followed by sequential manipulations and cast applications;
- Even with flexible hindfoot, soft tissue release must usually accompanied by osteotomy of either the first metatarsal of medial cuneiform.
- First metatarsal osteotomy.
- 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.
- Address claw toes.
Pic of Patient with ankle and hindfoot varus prior to surgical reconstruction
Pre and Postop Cavus Reconstruction with calcaneus and first metatarsal osteotomy