Foot Conditions - Anatomy 1st Year Viva

1. FLAT FOOT (Pes Planus)

Definition

Anatomy Basis

• Bones: Calcaneus, talus, navicular, cuneiforms, and 1st-3rd metatarsals
• Ligaments: Spring ligament (plantar calcaneonavicular ligament) - most important; plantar fascia
• Muscles: Tibialis posterior (dynamic key support), flexor hallucis longus, intrinsic foot muscles
• Plantar fascia: Acts as a tie-beam holding the arch

Types (Important for Viva!)

Key Facts

• All children under 3 years have physiological flat feet (fat pad obscures arch)
• 15% of adults have flat feet - influenced by familial and racial factors
• Flexible flat foot = no treatment needed if painless
• Rigid flat foot = due to tarsal coalition (most commonly calcaneonavicular bar) or inflammation - needs investigation

Clinical Test

2. CLUB FOOT (Congenital Talipes Equinovarus - CTEV)

Definition

The Four Components (Mnemonic: CAVE)

Anatomy of the Deformity

• The talonavicular joint is subluxed - navicular is displaced medially relative to the talar head
• Ligaments (especially calcaneofibular) are shortened and thickened, containing contractile myofibroblasts
• Gastrocsoleus and tibialis posterior muscles are smaller than normal with increased connective tissue
• Dorsalis pedis artery supply may be diminished

Epidemiology

• Incidence: 1-6 per 1000 live births
• More common in boys; bilateral in 50% of cases
• Familial tendency with multifactorial inheritance
• Causes: mostly idiopathic; neuromuscular causes include spina bifida and arthrogryposis; syndromic causes include trisomy 15

Treatment

• Ponseti method = gold standard - serial above-knee plaster casts beginning within weeks of birth, correcting CAVE deformity in sequence; percutaneous Achilles tenotomy for residual equinus (needed in ~90%); followed by foot abduction orthosis (FAO) worn for up to 4 years
• Corrects 95% of idiopathic cases without formal surgical release
• Surgical release reserved for failures or non-idiopathic cases

3. METATARSALGIA

Definition

Anatomy Basis

• Metatarsal heads bear weight during the toe-off phase of walking
• Under each metatarsal head lies a fat pad that cushions the load
• The plantar plate (fibrocartilaginous) stabilizes the metatarsophalangeal (MTP) joint
• Intrinsic muscles (lumbricals, interossei) maintain balance of MTP joints

Causes (Classify as Primary / Secondary)

• Primary: Abnormal metatarsal length or angle, cavus foot, tight gastrocnemius
• Secondary: Rheumatoid arthritis, hallux valgus (increased load on 2nd MTP), Freiberg's disease, Morton's neuroma, claw toes

Key Anatomy Points for Viva

• Pain is over the plantar surface of metatarsal heads (2nd most commonly)
• Fat pad migration = loss of protective padding under heads
• Associated with transfer metatarsalgia: when one metatarsal is surgically shortened, load shifts to adjacent metatarsals
• Treatment: offloading with metatarsal pads, proximal IP joint resection and MTP soft-tissue release; distal metatarsal osteotomy to elevate and proximally translate metatarsal head

4. PLANTAR FASCIITIS

Definition

Anatomy (Most Important for Viva!)

• Originates from the medial tuberosity of the calcaneus
• Inserts into the bases of the proximal phalanges (at the toes)
• Supports the longitudinal arch of the foot - acts as a tie-beam (windlass mechanism)
• During toe-off, toe extension tightens the fascia, which raises the arch (Windlass mechanism)

Pathology

• Overuse and increased strain (excessive running, prolonged standing, obesity) → microtears at the calcaneal origin
• Leads to disorganization of collagen fibers and degeneration
• Can trigger a traction osteophyte (calcaneal spur) at the insertion
• It is a degenerative process (fasciosis), not primarily inflammatory - though called "fasciitis"

Key Risk Factors

• BMI > 30 kg/m² (biggest risk factor)
• Tight gastrocnemius-soleus complex
• Excessive running or prolonged standing
• Cavus or flat foot

Classic Clinical Features

• First-step pain in the morning (most characteristic) - due to re-injury of the healing fascia after overnight rest
• Pain after prolonged sitting
• Tenderness at the medial plantar tuberosity of the calcaneus
• MRI shows thickening of plantar fascia at calcaneal insertion

Treatment

1. Conservative (90-95% resolve within 1 year):
   • Plantar fascia-specific stretching + Achilles tendon stretching (key)
   • Cushioned heel inserts, night splints, NSAIDs
   • Corticosteroid injection (short-term relief only, risk of fat atrophy/fascia rupture)
   • Platelet-rich plasma (PRP), extracorporeal shock wave therapy (ESWT)
2. Surgical (< 5% of cases): Limited release of medial half of plantar fascia
   • Caution: complete release risks arch collapse and lateral column overload

Quick Comparison Summary for Viva