Pes cavus/supinated foot
High arched foot. Literature is confusing regarding terminology.
1. Anterior cavus
a) Total type – plantarflexion of entire forefoot (also called simple pes cavus)
b) Local type – plantarflexion of first ray (also called pes cavovarus)
2. Posterior type – high inclination of calcaneus in relation to talus (also called pes calcaneocavus)
3. Combination (global) – anterior and posterior – (also calcaneocavus deformity)
Can also be classified if it is flexible, semiflexible or rigid.
Up to half are idiopathic – rest have underlying neurological problem (eg Charcot-Marie-Tooth disease; poliomyelitis; Friedreichs ataxia). Most have a rigid plantarflexed first ray supinatory force at subtalar joint ( cavus appearance) – amount of supination at subtalar joint will depend on ranges of motion of first ray and midtarsal joints.
Exaggerated medial longitudinal arch; plantarflexion of forefoot on rearfoot; plantarflexed first ray; limited ankle joint dorsiflexion; tarsal ‘humping’; plantar hyperkeratosis; claw toes; inverted rearfoot; history of ankle sprains.
Classic x-ray features – high calcaneal inclination angle; high metatarsal declination angle; prominent sinus tarsi (the ‘bullet hole’ sign)
Coleman Block test:
Investigate neuromuscular causes first
Conservative – foot orthoses (usually with forefoot valgus posting) and footwear accommodations
Surgical – soft tissue procedures (plantar fascia release, tendon release, tendon transfer); osteotomy (metatarsal, midfoot, calcaneus – depends on location of deformity); bone stabilisation procedures (eg triple arthrodesis)