Boutonniere deformity

Boutonniere Deformity

A hand showing boutonniere deformity

Boutonniere deformity is a condition affecting the fingers, characterized by the flexion of the proximal interphalangeal joint (PIP) and hyperextension of the distal interphalangeal joint (DIP). This deformity is commonly associated with rheumatoid arthritis, but it can also result from trauma or other connective tissue disorders.

Pathophysiology

Boutonniere deformity occurs due to the disruption of the central slip of the extensor tendon that inserts into the base of the middle phalanx. This disruption leads to the inability to extend the PIP joint, while the lateral bands of the extensor tendon slip below the axis of the joint, causing the DIP joint to hyperextend.

Causes

The primary causes of boutonniere deformity include:

• Trauma: Direct injury to the dorsal aspect of the finger can lead to rupture of the central slip.
• Rheumatoid arthritis: Chronic inflammation can weaken the extensor mechanism, leading to deformity.
• Osteoarthritis: Degenerative changes can also contribute to the development of boutonniere deformity.

Diagnosis

Diagnosis of boutonniere deformity is primarily clinical, based on the characteristic appearance of the finger. A physical examination will reveal:

• Flexion at the PIP joint
• Hyperextension at the DIP joint

Close-up of a hand with boutonniere deformity

In some cases, imaging studies such as X-rays may be used to assess the extent of joint involvement and rule out fractures or other conditions.

Treatment

Treatment of boutonniere deformity depends on the underlying cause and the severity of the condition. Options include:

• Splinting: Non-surgical management often involves splinting the PIP joint in extension to allow the central slip to heal.
• Physical therapy: Exercises to improve range of motion and strengthen the surrounding muscles.
• Surgery: In cases where conservative treatment fails, surgical intervention may be necessary to repair the extensor mechanism.

Prognosis

The prognosis for boutonniere deformity varies. Early intervention with splinting and therapy can lead to good outcomes, especially in cases caused by trauma. However, in chronic conditions like rheumatoid arthritis, the deformity may be more challenging to correct.

Related Pages

• Rheumatoid arthritis
• Extensor tendon injuries
• Hand anatomy