A 35-Year-Old Man with Thumb Pain After a Fall

Differential Diagnosis

• Avulsion fracture of the first MCP sesamoid
• Bipartite sesamoid
• Rupture of the joint lateral ligament
• Rupture of the palmar plate

Figure 2.

Diagnosis
This patient suffered an avulsion fracture of the first MCP sesamoid.

Learnings/What to Look for

• This fracture can be very subtle, and is usually visible as an avulsion fragment in close proximity to the sesamoid
• It is most often associated with forceful hyperextension of the thumb, and may accompany dislocation
• Anatomic variant bipartite sesamoid can mimic this injury

Pearls for Urgent Care Management and Considerations for Transfer

• The patient may be placed in a thumb spica splint for healing and comfort
• Follow-up with primary care or orthopedics within 3-4 days
• Ice, elevation, and acetaminophen and/or ibuprofen for comfort
• Transfer for diagnostic uncertainty, intractable pain, open fracture, or concern for infection