A 5-Year-Old with Foot Pain of Unknown Origin

Differential Diagnosis

• Osteomyelitis
• Osteosarcoma
• Freiberg disease
• Grierson-Gopalan syndrome
• Kohler’s disease
• Navicular fracture

Diagnosis

This patient was diagnosed with Kohler’s disease, indicated by a small, flattened, wafer-like navicular tarsal bone with sclerosis and fragmentation. Note localized soft tissue swelling. This condition is also known as avascular necrosis of the navicular tarsal bone.

Learnings/What to Look for

• Generally, isolated bony tenderness without trauma in children is concerning for bony infection, especially if fever is present. X-ray is helpful to evaluate for other pathology such as tumors, trauma, and avascular necrosis
• The diagnosis of Kohler’s disease is made on plain radiographs which show a small, thin, sclerotic and often fragmented navicular tarsal bone. MRI could be complimentary
• Most children present between age 4 and 5 years of age with limp, a painful inner arch of foot, swelling, and tenderness in the region of the navicular bone
• Kohler’s disease occurs in children during the developmental phase prior to complete ossification of the navicular bone
• Kohler’s disease is caused by excessive repetitive strain on the bone and its blood supply, leading to a temporarily compromised blood supply and resulting in avascular necrosis

Pearls for Initial Management

• Management requires immobilization and referral to a pediatric orthopedic specialist. The bone eventually heals and results in normal growth, rarely requiring surgical care

Acknowledgment: Image and case presented by Experity Teleradiology (www.experityhealth.com/teleradiology).