Hypermobile Pes Planus (Flexible Flatfoot)
Key Points
- Most common pediatric foot condition (10-23% of population)
- Physiological in children under 6 years
- Characterized by loss of medial longitudinal arch during weight-bearing
- Usually asymptomatic and self-limiting
- Treatment mainly required for symptomatic cases
Definition
Hypermobile pes planus is characterized by flattening of the medial longitudinal arch during weight-bearing, with restoration of the arch when non-weight-bearing or standing on tiptoes. The condition involves ligamentous laxity and is typically bilateral.
Associated Syndromes & Conditions
- Ehlers-Danlos Syndrome
- Generalized joint hypermobility
- Skin hyperextensibility
- Higher risk of chronic pain
- Marfan Syndrome
- Associated with aortic root dilation
- Tall stature and long extremities
- Lens dislocation
- Down Syndrome
- Increased ligamentous laxity
- Higher prevalence of severe flatfoot
- Cerebral Palsy
- Often associated with spasticity
- May require more aggressive management
Pathophysiology
- Primary factors:
- Ligamentous laxity
- Developmental absence of arch
- Muscular weakness
- Secondary contributors:
- Obesity
- Tight Achilles tendon
- Accessory navicular bone
Clinical Features
Symptoms
- Often asymptomatic
- When symptomatic:
- Fatigue pain in feet, ankles, or legs
- Activity-related discomfort
- Early shoe wear along inner border
- Difficulty with prolonged standing/walking
Physical Examination
- Standing examination:
- Too many toes sign
- Heel valgus > 10 degrees
- Collapsed medial longitudinal arch
- Dynamic assessment:
- Restoration of arch with toe-standing
- Jack's test (dorsiflexion of great toe)
- Heel-rise test
- Range of motion:
- Ankle dorsiflexion
- Subtalar joint motion
- Midfoot flexibility
Diagnosis & Assessment
Clinical Tests
- Jack's Test
- Dorsiflexion of hallux
- Positive: arch formation
- Indicates flexibility
- Heel Rise Test
- Observe heel inversion
- Arch formation on toe-standing
- Beighton Score
- Assessment of generalized hypermobility
- Score ≥ 4 indicates hypermobility
Imaging
- Weight-bearing radiographs:
- AP, lateral, and oblique views
- Talar-first metatarsal angle
- Calcaneal pitch angle
- Talonavicular coverage angle
- Additional imaging:
- Stress radiographs
- CT/MRI (rarely needed)
Management Approach
Conservative Treatment
- Observation
- Primary approach for asymptomatic cases
- Regular monitoring until skeletal maturity
- Physical Therapy
- Arch strengthening exercises
- Tibialis posterior strengthening
- Balance training
- Proprioception exercises
- Orthotic Devices
- Custom orthoses for symptomatic cases
- UCBL orthosis for severe cases
- Supportive footwear
Surgical Management
- Indications:
- Failed conservative treatment
- Persistent pain
- Progressive deformity
- Significant functional limitation
- Procedures:
- Calcaneal lengthening osteotomy
- Subtalar arthroereisis
- Medial soft tissue reconstruction
- Triple arthrodesis (rarely in children)
Disclaimer
The notes provided on Pediatime are generated from online resources and AI sources and have been carefully checked for accuracy. However, these notes are not intended to replace standard textbooks. They are designed to serve as a quick review and revision tool for medical students and professionals, and to aid in theory exam preparation. For comprehensive learning, please refer to recommended textbooks and guidelines.
