Pes Cavus (Cavovarus Foot) in Adults
1. Overview / High-Yield Summary
Pes cavus is a structural foot deformity characterized by a persistently elevated medial longitudinal arch that does not flatten with weight bearing.
In adults, the deformity most commonly presents as cavovarus, combining:
high medial arch,
plantar-flexed first ray,
forefoot pronation/adduction,
hindfoot varus.
Pes cavus is not a diagnosis, but rather the end result of underlying muscle imbalance, most frequently of neurologic origin.
Failure to identify the underlying etiology and the driver of the deformity (forefoot vs hindfoot) leads to unsuccessful treatment and recurrence.
2. Etiology and Pathophysiology
2.1 Neuromuscular Causes (≈ 67%)
Neurologic disorders are the most common cause of pes cavus in adults.
Unilateral cavus deformity
Must prompt evaluation for:
tethered spinal cord,
syringomyelia,
spinal cord tumor.
Bilateral cavus deformity
Most commonly due to Charcot-Marie-Tooth (CMT) disease.
A negative family history does not exclude CMT.
Muscle Imbalance Mechanism (Classic Pattern)
Weak:
tibialis anterior,
peroneus brevis,
intrinsic foot muscles.
Relatively preserved / strong:
peroneus longus,
posterior tibialis,
triceps surae.
Resulting deformity cascade:
peroneus longus plantar-flexes the first ray,
medial forefoot contacts ground first,
subtalar joint supinates to maintain tripod contact,
progressive hindfoot varus develops,
initially flexible → later rigid.
2.2 Idiopathic Pes Cavus
Usually:
bilateral,
subtle,
slowly progressive.
Likely represents a subclinical neurologic lesion below detection threshold.
2.3 Traumatic Causes
Talar neck or body fracture malunion (varus),
Compartment syndrome,
Crush injury,
Severe burns.
These cases often present with fixed cavovarus deformity and limited subtalar motion.
3. Clinical Presentation
3.1 History
Common complaints include:
recurrent ankle sprains,
lateral ankle instability,
lateral foot pain,
painful plantar calluses:
first metatarsal head,
fifth metatarsal head or base,
medial heel.
stress fractures of:
fifth metatarsal,
fourth metatarsal,
navicular.
Associated conditions:
peroneal tendon tendinopathy or tears,
plantar fasciitis,
sesamoiditis,
progressive ankle arthritis.
3.2 Physical Examination
Key Inspection Findings
Elevated medial arch,
“Peek-a-boo heel” sign on anterior standing view,
Varus hindfoot,
Prominent first metatarsal head,
Clawing of toes.
Coleman Block Test (Critical Test)
Purpose: determines whether hindfoot varus is forefoot-driven or hindfoot-driven.
Technique:
A block is placed under the lateral foot.
First metatarsal head is unsupported.
Interpretation:
Hindfoot corrects to neutral/valgus → flexible hindfoot, forefoot-driven deformity.
Hindfoot remains in varus → rigid hindfoot deformity.
Clinical relevance:
Guides need for hindfoot osteotomy.
Additional Examination
Silfverskiöld test:
gastrocnemius tightness common.
Lateral ankle ligament integrity.
Peroneal tendon examination.
Neurologic screening:
intrinsic hand muscle wasting suggests CMT,
scoliosis suggests underlying neurologic disease.
4. Imaging
4.1 Weight-Bearing Radiographs (Essential)
Foot: AP, lateral, oblique
Ankle: AP, lateral
Typical Radiographic Findings
Increased calcaneal pitch (>30°),
Meary’s angle: 4° apex dorsal,
break due to plantar-flexed first ray.
AP talocalcaneal angle <20°,
Talonavicular overcoverage,
Forefoot adduction,
Sinus tarsi “see-through” sign,
Bell-shaped cuboid,
Lateral column overload and stress fractures.
4.2 Advanced Imaging
EMG/NCS:
indicated when CMT is suspected.
Genetic testing:
confirmatory after clinical and electrodiagnostic evaluation.
MRI:
peroneal tendon pathology,
cartilage damage,
osteochondral lesions.
Weight-bearing CT (WBCT):
useful in complex deformity analysis,
assesses hindfoot alignment and joint relationships.
5. Treatment Principles
Key Concept
Treatment must address:
the underlying etiology, and
the deformity driver (forefoot vs hindfoot).
Isolated correction of ankle instability or soft tissues will fail if cavovarus alignment is not corrected.
6. Nonoperative Treatment
Indicated primarily in mild, flexible deformities.
Options include:
accommodative footwear,
full-length semi-rigid orthoses:
lateral heel wedge,
recessed first ray,
lowered medial arch.
SMO or AFO for more severe deformities,
lace-up ankle brace or high-top shoes for instability.
Limitations:
rarely sufficient in moderate–severe adult cavus deformity.
7. Operative Treatment
Indicated for:
failure of conservative treatment,
progressive deformity,
recurrent ankle instability,
painful calluses,
stress fractures,
arthritic symptoms.
7.1 Forefoot-Driven Deformity
(Positive Coleman Block Test)
First metatarsal dorsiflexion osteotomy.
Corrects plantar-flexed first ray
Removes driver of hindfoot varus
Peroneus longus → brevis transfer.
Decreases plantarflexion force on first ray
Augments eversion without weakening it
Plantar fascia release (selected cases).
Lateral ankle ligament reconstruction if instability present.
Jones procedure (EHL transfer and IP fusion) for clawed hallux (if indicated).
7.2 Hindfoot-Driven Deformity
(Negative Coleman Block Test)
Lateralizing calcaneal valgus-producing osteotomy (e.g., Dwyer).
Converts varus heel to valgus
Restores hindfoot alignment
Combined with:
first ray dorsiflexion osteotomy (addresses forefoot pronation),
tendon transfers as needed.
Gastrocnemius recession or TAL for equinus.
7.3 Arthrodesis
Subtalar or triple arthrodesis:
reserved for advanced arthritis.
Generally avoided due to:
poor long-term functional outcomes.
7.4 Goals for reconstruction
Plantigrade foot
Stable hindfoot
Reduced lateral column overload
Prevention of recurrent lateral ankle instability
Improved gait and pain relief
8. Complications
Persistent ankle instability if cavus uncorrected,
Varus ankle arthritis,
Stress fractures (lateral column),
Peroneal tendon tears,
Plantar fasciitis,
Sesamoiditis.
9. Prognosis
Outcome depends on:
etiology (neurologic vs traumatic),
severity and rigidity of deformity,
accuracy of deformity analysis,
appropriate combination of procedures.
Early recognition and targeted correction provide the best functional outcomes.