3 – Congenital foot deformities

Basics of foot

DDH is the most common congenital problem of the musculoskeletal system
Congenital foot deformities are the second
Foot = everything distal to tibiotalar joint
Arches of the foot
- Soft tissues like muscles, tendons and ligaments are important in maintaining the arches of the foot
- The three arches form a triangle under the foot
- Transverse arch
- Lateral longitudinal arch
- Medial longitudinal arch
Characteristics of healthy foot
- Pain free
- Good muscle balance
- No contractures
- Heel in physiological position (no varus or valgus)
- Toes without deformity
Parts of foot
- The forefoot is comprised of the metatarsal bones and the phalanges
- The midfoot is comprised of the navicular, the cuboid, and the cuneiform bones
- The hindfoot is comprised of the talus and calcaneus
Function
- Dynamic functions
  - The medial structures (talus, navicular, cuneiform and first three metatarsal bones)
  - Provide shock absorption when walking
- Static functions
  - The lateral structures (calcaneus, cuboid, fourth and fifth metatarsal bones)
  - Provide stability
The majority of the pressure is on the calcaneus and the first two metatarsal bones
Forefoot deformities
- Pes adductus (skew-foot)
- Pes supinatus
Hindfoot deformities
- Often have associated forefoot deformities
- Clubfoot (talipes equinovarus)
- Vertical talus (rocker-bottom foot)

Clubfoot is one of the two hindfoot deformities (the other being rocker-bottom foot)
- It is a hindfoot deformity, but it also has associated forefoot deformities
Clubfoot is also called congenital talipes equinovarus (CTEV)
The clinical appearance involves
- Concave medial side and convex lateral side
  - Think banana pointing medially
- Heel varus
- Adducted and supinated forefoot
- Can be unilateral or bilateral
Congenital clubfoot
- Common
  - The 2nd most common congenital deformity
- Incidence depends on race
- Etiology: Neuromuscular problem
  - Dominant posterior musculature
  - Weak peroneus muscles
  - Shortened Achilles tendon
- For management of congenital clubfoot: see topic 24
Acquired clubfoot
- Rare
- Etiology of acquired clubfoot
  - Paralytic causes
    - Paralysis of muscles can cause clubfoot
  - Teratologic (tibia hypoplasia)
  - Syndromic (Larsen/Marfan syndrome)
  - Secondary (arthrogryposis)
  - Postural (mechanical)
    - Due to abnormal intrauterine position of feet
Pathology of clubfoot
- Heel varus and equinus
- Forefoot adductus and supinatus
- Concave medial side
- Convex lateral side
- The long axis of the talus and calcaneus run parallel to each other in the AP and lateral views

See topic 22 for more general information about clubfoot
Conservative treatment
- The conservative technique for treating congenital clubfoot is called the Ponseti method
- This method is the standard of care, and is successful in almost 100% of cases
- The Ponseti method takes 4 – 6 weeks
- Begins as soon as the baby’s skin is ready (can be even after 2 days after birth)
- Procedure
  - The foot is manually manipulated into a more correct position
    - This type of manipulation is called talus derotation
    - Talus derotation creates an angle between talus and calcaneus
  - The foot is then casted in that position
  - After some days the cast is removed, the foot is once again manipulated and re-casted
  - This procedure is repeated multiple times until the deformity is confirmed corrected by x-ray
  - Achilles tenotomy is finally performed
Operative treatment
- Needed if conservative treatment is unsuccessful
- Surgical treatment should finish before 12 months of age
Aftercare
- Exercises
- Follow-up (with x-ray)
  - Taking x-rays is important to determine that the bones are being corrected and not just the soft tissue is being moved
- Splinting – important to keep the foot in normal position

Rocker-bottom foot (vertical talus) is one of the two hindfoot deformities (the other being clubfoot)
- Despite being a hindfoot deformity, vertical talus has associated forefoot deformities
It is a congenital disorder
The clinical appearance involves
- Concave lateral side and convex medial side
  - Think banana pointing laterally
- Concave dorsal side and convex plantar side
- A prominent calcaneus
Vertical talus and clubfoot have opposite macroscopic appearance (they’re opposite deformities)
Etiology
- Structural (genetic)
- Paralytic (neurologic)
- Teratologic (fibula hypoplasia)
- Symptomatic (Larsen/Marfan syndrome)
- Postural (mechanical)
Pathology
- The talus sits vertically instead of normally
- The angle between the long axis of the talus and calcaneus in the AP view is > 32 degrees
- The angle between the long axis of the talus and tibia in the lateral view is > 120 degrees
Treatment
- Start with conservative treatment
  - Manipulation + cast (similar to Ponseti method, but in the opposite direction)
  - Check result with X-ray
- Perform surgery before 1 year of age if results are not satisfactory
  - Surgery of congenital foot abnormalities must be finished before 1 year (before the child will stand)