Definition
A tarsal coalition is an abnormal fibrous, cartilaginous or osseous connection between two or more tarsal bones due to failure of normal segmentation.
Common types
- calcaneonavicular coalition
- talocalcaneal coalition
Presentation
Symptoms commonly appear in late childhood or adolescence as the coalition becomes more rigid.
- painful rigid flatfoot
- recurrent ankle sprains
- restricted subtalar motion
- peroneal spasm in some cases
Imaging
- weight-bearing radiographs
- oblique view for calcaneonavicular coalition
- CT defines osseous anatomy
- MRI is useful for fibrous or cartilaginous coalition
Treatment
Non-operative
- activity modification
- NSAIDs
- orthoses
- short period of immobilisation for symptomatic flares
Operative
Coalition resection may be appropriate for persistent symptoms when adjacent joints are preserved. Arthrodesis is considered when coalition is extensive, deformity is severe or significant adjacent arthritis exists.