A 13-year-old girl complains of activity-related pain along the medial border of her foot with a prominent bony lump. The arch flattens slightly on standing but corrects on tiptoeing. Radiograph shows a small ossicle adjacent to the navicular tuberosity separated by a fibrocartilaginous junction. The most likely diagnosis is:
- A Kohler disease
- B Type II accessory navicular ✓
- C Tarsal tunnel syndrome
- D Stage II posterior tibial tendon dysfunction
Correct answer: B. Type II accessory navicular
Explanation
B type II accessory navicular is a secondary ossification centre connected to the navicular body by a fibrocartilaginous synchondrosis into which the tibialis posterior tendon inserts. Traction across this junction in an adolescent girl produces medial arch pain and a prominent tuberosity, and it predisposes to later posterior tibial tendon dysfunction. Kohler disease is avascular necrosis of the navicular in younger children with sclerosis and fragmentation. Tarsal tunnel syndrome causes burning neurological symptoms, and stage II PTTD occurs in adults with fixed deformity.
Reference: Campbell's Operative Orthopaedics, 14th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.