Updated: 9/22/2018

Cavovarus Foot in Pediatrics & Adults

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https://upload.orthobullets.com/topic/4063/images/Colman block test - flexible hindfoot - courtesy Miller_moved.png
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https://upload.orthobullets.com/topic/4063/images/meary.jpg
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Introduction
  • Deformity characterized by   
    • cavus (elevated longitudinal arch) 
    • plantarflexion of the 1st ray and forefoot pronation
    • hindfoot varus
    • forefoot adduction
  • Epidemiology
    • seen in both pediatric and adult populations
    • 67% due to a neurologic condition 
    • when bilateral often hereditary or congenital
  • Pathophysiology
    • neurologic
      • diagnosis of neurologic condition is critical to render appropriate treatment 
      • unilateral - rule out tethered spinal cord or spinal cord tumor
      • bilateral - most commonly Charcot-Marie-Tooth (CMT) disease
      • muscle imbalances generate deformity 
        • weak tibialis anterior and peroneus brevis overpowered by strong peroneus longus and posterior tibialis  
        • results in plantarflexed 1st ray and forefoot pronation with compensatory hindfoot varus
          • with the 1st metatarsal plantflexed and forefoot pronated, the medial forefoot strikes ground first
          • the subtalar joint supinates to bring the lateral forefoot to the ground and maintain three-point contact, resulting in hindfoot varus
          • while initially flexible, hindfoot varus can become rigid with time
    • idiopathic
      • usually subtle and bilateral
    • traumatic 
      • talus fracture malunion
      • compartment syndrome
      • crush injury
  • Associated conditions
    • conditions which present with cavovarus foot
      • Charcot-Marie-Tooth disease  
      • Cerebral palsy
      • Freidreich's ataxia 
      • Spinal cord lesions
      • Polio
    • conditions caused by the presense of cavovarus foot
      • see complications below
  • Prognosis
    • depends on
      • deformity severity
      • etiology
      • patient age
Presentation
  • History
    • recurrent ankle sprains and lateral ankle pain
      • peroneal tendon pathology
    • lateral foot pain
      • excessive weight bearing by the lateral foot due to deformity
      • can result in 5th metatarsal stress fractures
    • painful plantar calluses under 1st metatarsal head and 5th metatarsal head or base
    • plantar fasciitis
      • elevated medial arch, forefoot pronation and tight gastronemius lead to contracture of the plantar fascia
  • Physical exam
    • Coleman block test 
      • evaluates flexibility of hindfoot deformity  
      • technique
        • place 1" block under the lateral foot
        • eliminates contribution of the plantarflexed 1st ray and forefoot pronation to the hindfoot deformity
      • findings
        • flexible hindfoot will correct to neutral or valgus when block placed under lateral aspect of foot 
        • rigid hindfoot will not correct to neutral
      • guides surgical treatment
        • flexible hindfoot deformities resolve with forefoot corrective procedures
        • rigid hindfoot deformities require corrective hindfoot osteotomy in addition to forefoot procedures
    • peek-a-boo heel  
      • anterior standing examination shows varus heel "peeking" around the ankle 
    • prominent first metatarsal fat pads
    • Silfverskiold test
      • check dorsiflexion with both knee flexion and knee extension
        • if tight only with knee extension, then gastrocnemius is tight
        • if tight also with knee flexion, then soleus is also tight
      • gastronemius tightness often present with cavovarus foot
    • altered gait
      • unstable base of support
      • increased double limb stance and decreased single limb stance
    • wasting of 1st dorsal interosseous muscle of the hand
      • suggestive of CMT
    • spine exam
      • scoliosis is suggestive of CMT
      • spinal dysraphism 
Imaging
  • Radiographs
    • recommended views
      • standing anteroposterior (AP), lateral radiographs of the ankle
      • standing AP, lateral and oblique radiographs of the foot
    • findings
      • AP foot
        • talocalcaneal angle < 20° (nl 20-45°)  
          • hindfoot varus
        • talonavicular overcoverage  
          • talonavicular angle > 7° indicates forefoot adduction
        • metatarsal overlap  
          • forefoot pronation
      • lateral foot
        • lateral talo-first metatarsal angle (Meary's angle) > 4° apex dorsal  
          • break in Meary's line caused by plantarflexion of the 1st ray
        • calcaneal pitch or inclination angle > 30°  
        • sinus tarsi see-through sign and double talar dome sign  
          • due to external rotation of the ankle and hindfoot relative to the xray cassette, which is placed along the medial border of the adducted forefoot
        • bell-shaped cuboid
        • increased distance between base of 5th metatarsal and medial cuneiform
      • oblique foot
        • metatarsal stress fractures
        • calcaneonavicular coalitions
Studies
  • Electrodiagnostic Studies (EMG/NCS)
    • diagnostic algorithm for CMT generally dictates
      • a neurologic physical exam
      • electrodiagnostic studies
      • genetic testing
  • Genetic studies
    • used to confirm diagnosis after physical exam and electrodiagnostic studies
Treatment
  • Nonoperative
    • accomodative shoe wear
      • indications
        • rarely sufficient except in mild deformity
    • full-length semi-rigid insole orthotic with a depression for the first ray and a lateral wedge 
      • indications
        • mild cavus foot deformity in adult (not indicated in children)
    • supramalleolar orthosis (SMO) 
      • indications
        • more severe cavovarus deformity recalcitrant to shoewear accomodations
    • ankle foot orthosis (AFO)
      • indications
        • may be needed if equinus also present, resulting in equinocavovarus foot deformity
        • works best if equinus is a dynamic defomrity (not rigid)
    • lace-up ankle brace and/or high-top shoe or boots
      • indications
        • may consider in moderate deformities when patient does not tolerate the more rigid bracing with an SMO or AFO
  • Operative
    • soft tissue reconstruction
      • indications
        • failure of nonoperative treatment
      • performed with a combination of the following procedures
        • plantar release
          • indications 
            • cavus deformity
          • technique 
            • plantar fascia release
            • Steindler stripping (release short flexors off the calcaneus)
        • peroneus longus to brevis transfer
          • indications 
            • plantar flexed first ray
          • technique 
            • decreases plantarflexion force on first ray without weakening eversion
        • posterior tibial tendon transfer
          • indications 
            • muscle imbalance 
              • posterior tibialis typically is markedly stronger than evertors and maintains strength for a long time in most cavovarus feet
            • may consider transfer of posterior tibialis to dorsum of foot if severe dorsiflexion weakness of anterior tibialis
        • lengthening of gastrocnemius or tendoachilles (TAL) 
          • indication 
            • true ankle equinus
            • gastrocnemius recession produces less calf weakness and can be combined with plantar release simultaneously
            • TAL should be staged several weeks after plantar release
        • 1st metatarsal dorsiflexion osteotomy 
          • indications 
            • flexible hindfoot varus deformities (normal Coleman block test)  
              • corrects the forefoot pronation driving the hindfoot deformity
        • lateral ankle ligament reconstruction (e.g. Broström ligament reconstruction) 
          • indications 
            • chronic ankle instability due to lignamentous incompetence following long-standing cavovarus
        • Jones transfer(s) of EHL to neck of 1st MT and lesser toe extensors to 2nd-5th MT necks 
          • indication 
            • toe clawing combined with cavus foot  
            • performed if the indication is met and time permits
    • lateralizing calcaneal valgus-producing osteotomy
      • indications 
        • rigid hindfoot varus deformity (abnormal Coleman block test) 
    • triple arthrodesis
      • indication 
        • almost never indicated due to very poor long-term results
Complications
  • Ankle instability 
    • standard lateral ankle ligament reconstruction will fail if cavovarus deformity is not concomitantly addressed
    • untreated can lead to varus ankle arthritis
  • Stress fractures
    • 5th metatarsal base (Jones fracture)
    • 4th metatarsal
    • navicular
    • medial malleolus 
  • Hallux sesamoiditis
    • overload from plantarflexed 1st metatarsal head
  • Peroneal tendon pathology
    • tendonitis, tears, subluxation or dislocation 
    • peroneus brevis most commonly involved
  • Plantar fasciitis
    • contracture of the plantar fascia results from elevated medial arch, forefoot pronation and tight gastronemius
 

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(OBQ04.90) An 18-year-old male presents with recurrent ankle sprains of the left ankle and painful callus underneath the 5th metatarsal. Standing examination is shown in Figures A and B. During Coleman block testing the hindfoot is positioned in 3 degrees of valgus. The peroneus brevis and anterior tibialis have 4/5 strength compared to 5/5 strength in peroneal longus, gastrocsoleus complex, and posterior tibialis. Using a semi-ridged orthotic with a recess for the head of the first ray and lateral hindfoot posting has failed to improve symptoms. Which of the following is most appropriate as one part of the surgical plan?? Review Topic

QID: 1195
FIGURES:
1

Peroneus brevis to longus transfer with medial calcaneal slide osteotomy

31%

(209/671)

2

Triple arthrodesis

2%

(15/671)

3

First ray dorsiflexion osteotomy with plantar fascia release

62%

(413/671)

4

Subtalar arthrodesis

2%

(11/671)

5

First tarsometatarsal joint arthrodesis and metatarsophalangeal capsular release

2%

(16/671)

ML 3

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PREFERRED RESPONSE 3
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(OBQ09.32) What is the preferred orthotic device for a symptomatic adult foot deformity that is shown in Figure A, has no arthritis on radiographs, and responds to Coleman block testing as shown in Figure B? Review Topic

QID: 2845
FIGURES:
1

Short walker boot

0%

(8/2666)

2

Accommodative custom orthotics

5%

(136/2666)

3

Lace up soft ankle brace

1%

(15/2666)

4

Medial hindfoot posting with arch support

16%

(438/2666)

5

Lateral hindfoot posting with recessed first ray

77%

(2060/2666)

ML 2

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PREFERRED RESPONSE 5
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