- Spontaneous adult onset tarsal navicular bone osteonecrosis
- Adults in 40-60 years
- More common in women
- Ipsilateral
- Imaging
- Weight-bearing radiographs of the foot
- Decreased volume and increased sclerosis
- A comma-shaped deformity
- Fragmentation of the navicular bone into two unequally sized major fragements
- Progressive perinavicular osteoarthritis
