Adult cavovarus foot

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J Am Acad Orthop Surg. 2005 Sep;13(5):302-15.

Adult cavovarus foot.

Younger AS, Hansen ST Jr.

Foot and Ankle Program, Providence Health Care, University of British

Columbia, Vancouver, Canada.

Cavovarus foot deformity, which often results from an imbalance of

muscle forces, is commonly caused by hereditary motor sensory

neuropathies. Other causes are cerebral palsy, cerebral injury

(stroke), anterior horn cell disease (spinal root injury), talar neck

injury, and residual clubfoot.

In cavovarus foot deformity, the relatively strong peroneus longus

and tibialis posterior muscles cause a hindfoot varus and forefoot

valgus (pronated) position. Hindfoot varus causes overload of the

lateral border of the foot, resulting in ankle instability, peroneal

tendinitis, and stress fracture. Degenerative arthritic changes can

develop in overloaded joints.

Gait examination allows appropriate planning of tendon transfers to

correct stance and swing-phase deficits. Inspection of the forefoot

and hindfoot positions determines the need for soft-tissue release

and osteotomy.

The block test is invaluable for assessing the cause of

hindfoot varus. Prolonged use of orthoses or supportive footwear can

result in muscle imbalance, causing increasing deformity and

irreversible damage to tendons and joints.

Rebalancing tendons is an early priority to prevent unsalvageable

deterioration of the foot. Muscle imbalance can be corrected by

tendon transfer, corrective osteotomy, and fusion. Fixed bony

deformity can be addressed by fusion and osteotomy.