Kohler’s disease

definition

· osteonecrosis of the navicular

epidemiology

· present at age 4-6 yrs

· more common in males (5:1)

· bilateral in 20%

aetiology

· repetitive trauma to maturing ossific nucleus

clinical features

· pain and soft tissue swelling over navicular

radiology

· flattening and sclerosis of navicular

treatment

· usually resolves within 18-36 mths

· aim to provide symptomatic relief

· short-leg cast for 6-8 wks

Accessory navicular

definition

· accessory bone of foot

· lies in medial plantar border of navicular

· may be

· sesamoid of tibialis posterior tendon

· connected to navicular by fibrocartilagenous union

· fused to navicular

epidemiology

· common finding

· 5-25% of feet

clinical features

History

· painful lump over medial aspect of foot

Examination

· prominence over tuberosity of navicular

· often associated with flexible flat foot

Radiology

· accessory ossicle near tuberosity OR

· cornuate-shaped navicular

treatment

Nonoperative

· foot orthosis to prevent pressure

Operative

· simple excision

· tendon of tibialis posterior split

· ossicle and prominent navicular tuberosity removed

· tendon repaired

· Kidner procedure of rerouting tibialis posterior not necessary