II. Epidemiology
- Prevalence: <1% of U.S. population
- Gradual onset in adolescence
III. Etiology
IV. Pathophysiology
- Tarsal Coalition results in range of motion loss
- Local irritation
- Protective spasm of the peroneal Muscles
V. Types
- Fusion or bridge type
- Fibrous fusion (Syndesmosis)
- Cartilaginous fusion (Synchondrosis)
- Osseous fusion (Synostosis)
- Distribution of fusion
- Calcaneonavicular coalition (53% of cases)
- Talocalcaneal coalition or Subtalar coalition (37%)
VI. Symptoms
- Bilateral involvement in 50% of cases
- Foot stiffness
- Painful limp
VII. Signs
- Tenderness over peroneal tendons or hindfoot
- Heel everted
- Subtalar joint (midtarsal) range of motion
- Limited and painful
- Provocative maneuvers
- Passive Stretching of peroneal tendons
- Forefoot Adduction and Inversion
- Swelling suggests other comorbid condition
VIII. Radiology: Foot XRay
- Associated findings: Hindfoot Arthritis
- Calcaneonavicular coalition (best visualized on oblique AP film)
- Talocalcaneal coalition (observe for secondary signs on lateral film)
- Talar beaking (talar head with superior margin flaring)
- Lateral talar process with flattening and broadening
- Posterior talocalcaneal joint narrowing
- C-Sign (Medial outline of talar dome and posteroinferior outline of substentaculum tali)
- Absent middle Facet Sign (Subtalar joint middle facet is obscured on standing lateral view)
IX. Management
- Asymptomatic
- No treatment is needed
- Orthotics are not recommended in asymptomatic flat foot in children
- Symptomatic
- Rest
- Heat
- NSAIDs
- Short Leg Walking Cast or boot intermittently as needed
- Surgery often necessary
- Arthritis
- Arthrodesis of hindfoot and Tarsal Navicular
- Tarsal Coalition
- Bony and cartilaginous bar resection
- Arthrodesis of hindfoot and Tarsal Navicular
- Indicated for failed resection
- Arthritis