Boutonniere Deformity
What is Boutonniere deformity?
Boutonnière deformity is a finger injury that affects the tendon system on the back of the finger, leading to a characteristic bent posture. The deformity causes the middle joint of the finger (PIP joint) is bent toward the palm, while the tip of the finger (DIP joint) is bent backward (hyperextended). It most commonly affects the ring or little finger, but any finger (including the thumb, rarely) can be involved.
What causes Boutonniere deformity?
Boutonnière deformity occurs when the central slip of the extensor tendon, located on the top part of the finger, is damaged or ruptured.
Common causes include:
- Trauma: forceful blow to a bent finger (e.g., sports injuries)
- Lacerations to the back of the finger
- Rheumatoid arthritis (most common non-traumatic cause)
- Finger dislocations or fractures
- Untreated or improperly treated finger sprains
When the central slip fails, the lateral bands of the tendon move downward, pulling the finger into the deformity.
What are the symptoms of Boutonniere deformity?
Early symptoms
- Pain and swelling at the middle (PIP) joint
- Difficulty straightening the PIP joint
- Tenderness on the back of the finger
Later symptoms
- Persistent bending of the PIP joint
- Hyperextension of the end (DIP) joint
- Stiffness and loss of grip strength
- Difficulty with fine motor tasks
What are the treatment options of Boutonniere deformity?
Treatment depends on how early it is diagnosed. Non-Surgical Treatment (Early / Acute) may include use of Anti-inflammatory medication, ice and elevation (early phase), and continuous PIP joint extension splinting. Splint must be worn 24/7—even brief bending can reset healing time. If the deformity is classified as chronic or severe, surgical intervention may be indicated by the orthopedic surgeon. Indications for surgery may include delayed diagnosis (>3–4 weeks), tendon rupture not responding to splinting, or associated fractures or rheumatoid deformity. In addition, the surgeon may also recommend other protocols. Splinting may be suggested to correct forces to decrease deformity.
What is the rehabilitation for a Boutonniere deformity?
Rehabilitaion is usually guided by a Certified Hand Therapist (CHT) or OT specialized in upper extremity injuries. Rehabilitation will occur in phases; splinting phase, early motion, strengthening, and return to prior level of function.
- Phase 1 (Early Motion) – Gentle active PIP flexion, continue night splinting, and avoid forceful gripping
- Phase 2 (Strengthening) – Gradual resistance exercises, functional hand tasks, tendon gliding exercises
- Phase 3 (Return to Function) – Full range-of-motion goals, and sport- or work-specific activities
Full rehab can take up to 3–4 months, or longer in chronic cases.
The rehabilitation process and timeline will vary based on multiple factors such as instability, delayed healing, or other guidelines from the surgeon. It is important that you see a therapist that specializes in Orthopedic care of the Upper Extremity such as a Certified Hand Therapist, to ensure proper progression through the rehab process to avoid re-injury.
