Definition:

'Boutonniere deformity' is a deformed position of the fingers or toes, in which the joint nearest the knuckle (PIP) is permanently bent toward the palm while the farthest joint (DIP) is bent back away (proximal interphalangeal joint flexion with distal interphalangeal joint hyperextension). It is commonly caused by injury or by an inflammatory condition like rheumatoid arthritis.

Symptoms:

• Joint nearest the knuckle (PIP) is permanently bent toward the palm while the farthest joint (DIP) is bent back away (PIP flexion with DIP hyperextension)
• Decreased ROM in the affected finger
• Cannot fully straighten finger
• Swelling and pain in the finger

Causes:

• Rheumatoid arthritis
• Forceful blow to a bent finger
• Deep cut to top of finger

Treatment:

• Finger splint
• Finger ROM and stretching
• Hand intrinsic muscle strengthening