Due to embryonic failure of segmentation of tarsal bones. Forming connecting bar between tarsal bones commonly calcaneonavicular and talocalcaneum. Less common in talonavicular and calcaneocuboidal. 70 % bilateral in calcaneonavicular and 50 % bilateral in talocalcaneal.
Tarsal coalition can be in form of
- Fibrous bar
- Cartilage bar
- Bone bar
Genetically inherited as autosomal dominant
Associated congenital abnormalities
- Fibular hemimelia
Clinical Presentation
- Most asymptomatic and painless
- Gradual onset pain
- Diffuse midfoot pain
- Stiffness
- Young adult
- Activity related pain
- Mechanical pain / discomfort
- Frequent ankle sprain
Clinical Examination
Hindfoot valgus
Forefoot Abduction
Limited subtalar motion
Too many toe sign
Positive Jack test (rigid flat foot)
Peroneal muscle spasm / contracture
Calf atrophy
Antalgic gait
Investigation
Plain radiograph
AP
Lateral
- Dorsal beaking of talus
- Calcaneal elongation anteriorly
- Narrow posterior subtalar joint
Oblique
- Calcaneonavicular bar
Axial
- Medial facet coalition
CT Scan
- If normal finding on plain radiograph or equivocal
- Preoperative confirmation and to rule out other coalition
- Bilateral CT
- Good in showing talocalcaneal coalition bar
Management
- Mostly asymtomatic
- Most resolve spontaneously with time and rest / splint
- Activity modification
- Rest
- Ankle foot orthosis / splintage
- Below knee walking cast 6 weeks
- NSAIDS
Surgical managemant
- If fails non operative
- Recurrent symptoms
- Resection of calcaneonavicular bar with interposition of extensor digitorium brevi
- Resection of talocalcaneal bar with interposition of fat graft
- Subtalar arthrodesis if coalition bar is > 50 %
Recurrent pain post operatively
- Incomplete bar resection
- Bar recurrence
- Missed coalition
- Infection
Entries (RSS)