Updated: 10/15/2018

Equinovarus Foot

Topic
Review Topic
0
0
Techniques
3
https://upload.orthobullets.com/topic/4064/images/equinovarus.jpg
https://upload.orthobullets.com/topic/4064/images/equinovarus-foot.jpg
https://upload.orthobullets.com/topic/4064/images/equinovarus-gait.jpg
Introduction
  • Epidemiology
    • incidence
      • common foot deformity seen with
        • cerebral palsy (usually spastic hemiplegia)
        • Duchenne muscular dystrophy
        • residual clubfoot deformity
        • spina bifida
        • tibial deficiency (hemimelia)
          • though this condition is very rare
  • Pathophysiology
    • pathomechanics
      • imabalance of invertors and evertors (invertors overpower the evertors)
      • relative overpull of
        • tibialis posterior and/or 
        • tibialis anterior 
        • gastoc-soleus complex
      • example: in cerebral palsy
        • the causative muscles for the varus are the 
          • anterior tibialis (AT) in 1/3 of patients
          • posterior tibialis (PT) in 1/3 and 
          • both the AT and PT in the remaining 1/3
    • foot deformity muscle imbalance overview 
Presentation
  • Symptoms
    • pain
      • painful weight bearing over the lateral border of the foot
    • instability
      • during stance phase
      • results in shortened single limb stance
    • poor shoe and/or brace fitting and shoe wear problems
  • Physical Exam
    • inspection
      • inverted heel (tibialis posterior typically implicated)
      • supinated forefoot (tibialis anterior)
      • callous and pain along lateral border
      • intoeing gait (foot progression angle is more internal than knee progression angle)
    • provocative tests
      • active dorsiflexion of foot
        • if foot supinates with dorsiflexion, the anterior tibialis is implicated
      • confusion test
        • indications
          • used in those with poor selective motor control, as in CP, and cannot dorsiflex foot when asked)
        • method
          • patient performs active hip flexion (with or without resistance) while seated
          • results in ankle dorsiflexion due to mass action pattern of leg
          • if the foot supinates with dorsiflexion, the tibialis anterior is likely a contributing to the varus deformity
    • Coleman block test
      • indications
        • to test rigidity of the varus deformity
        • do not do this in children with limited balance such as CP
      • method
        • patient stands on a block with the first ray off the block 
        • if the varus corrects, the deformity is flexible
    • manual manipulation of the hindfoot
      • can be used to asses rigidity of the varus deformity
        • passive eversion of the hindfoot past neutral demonstrates that the varus deformity is flexible
Imaging
  • Radiographs
    • recommended views
      • AP + lateral of foot
    • findings
      • forefoot adduction is seen on the AP radiograph 
      • the talus and calcaneus are more parallel than in typical feet
      • one can often "look down" the sinus tarsi through a visual hole there
      • the calcaneus looks foreshortened on the lateral view
      • the metatarsals are often "stacked" on the lateral view (instead of being in line with one another)
      • stress fractures along the fourth and/or fifth metatarsal bases can develop secondary to repetitive load along the lateral border of the foot.
Studies
  • dynamic EMG
    • may be useful in distinguishing whether tibialis anterior and/or tibialis posterior is/are causing the varus
    • in CP, 
Treatment
  • Nonoperative
    • ankle foot orthosis (AFO)
      • helps provide stability for the foot and a more stable base of support during gait
      • should have a "wrap around" hindfoot component of the brace to help control the varus and minimize pressure points
    • serial casting 
      • indication
        • rigid deformity
    • botulinum toxin injection into tibialis posterior and/or gastrocnemius
      • indication
        • flexible or dynamic deformities
        • desire to delay surgery
  • Operative
    • gastrocnemius recession or tendoachilles lengtheing (TAL) for equinus
      • indications
        • fixed equinus unresponsive to non-operative measures
        • gastrocnemius recession should be performed if the anke can be brought to neutral or above neutral with the knee flexed and hindfoot inverted, but not when the knee is extended
        • TAL should be performed if the ankle can not be dorsiflexed to neutral with the knee flexed or extended
    •  split-posterior tibialis tendon transfer [SPOTT] or posterior tibial tendon lengthening (PTTL)
      • indications 
        • soft tissue balancing is required if varus is flexible or rigid
        • varus foot recalcitrant to non-operative measures and posterior tibialis contributing to varus (dynamic EMG, when available is helpful)
        • tibialis posterior spastic in both stance and swing phase (continous activity)
        • common patient:  spastic hemiplegia in ages 5 to 7 years old
      • technique
        • SPOTT
          • reroute half of tendon laterally and insert into peroneus brevis
        • PTTL
          • fractional lengthening of the tendon in the distal third of the lower leg
        • either PTTL or SPOTT may be combined with SPLATT
      • outcomes
        • results for both surgeries are good, without clear indications for transfer versus lengthening
    • split-anterior tibialis tendon transfer [SPLATT] 
      • indications
        • overactive anterior tibialis on EMG
        • when anterior tibialis contributes to varus foot, whether flexible or rigid varus deformity
      • technique
        • split anterior tibialis transfer to cuboid, peroneus tertius, or peroneus brevis
        • may be combined with SPOTT or PTTL
    • calcaneal osteotomy 
      • indications
        • required for a rigid hindfoot varus deformity
      • technique
        • lateral closing wedge osteotomy (Dwyer) to incur valgus to the heel, OR
        • lateral calcaneal sliding osteotomy to correct the varus
        • typically combined with soft tissue balancing (as above)
Complications
  • Overcorrection (resultant valgus deformity)
    • increased risk in
      • children who undergo surgery at younger age
      • children with diplegia (as oppose to hemiplegia)
  • Wound complications
    • most common with calcaneal osteotomy lateral incision
    • risk decreased by using absorbable suture
  • Hardware Pressure sores/ulcers
    • from buttons on bottom of foot (from SPLATT to cuboid)
    • has led some surgeons to always transfer SPLATT to peroneus tertius or brevis
 

Please rate topic.

Average 3.9 of 14 Ratings

Thank you for rating! Please vote below and help us build the most advanced adaptive learning platform in medicine

The complexity of this topic is appropriate for?
How important is this topic for board examinations?
How important is this topic for clinical practice?
Technique Guides (3)
ARTICLES (4)
Topic COMMENTS (6)
Private Note