Introduction
A boutonniere deformity happens when the tendon responsible for straightening the middle joint of the finger becomes injured, weakened, or overstretched. This injury causes the middle joint to bend (flex) while the end joint extends and pulls back (hyperextends), giving the finger a crooked appearance.
This deformity can lead to pain and reduced function. Treatment options include splinting, hand therapy, and surgery. Early intervention generally leads to better outcomes.
Anatomy
Fingers consist of three bones, known as phalanges, which are separated by two joints. The distal interphalangeal (DIP) joints are near the fingertips, while the proximal interphalangeal (PIP) joints are in the middle. Extensor tendons allow the fingers to straighten and extend.
Causes
Boutonniere deformity occurs when the extensor tendon attached to the middle phalanx is damaged, preventing the PIP joint from straightening and leaving it bent. The DIP joint hyperextends due to an imbalance in the extensor mechanism, resulting in a crooked, poorly functioning finger.
Conditions such as arthritis, burns, Dupuytren’s contracture, and injuries can damage the extensor tendon. The tendon may tear partially or completely, or it may remain intact while pulling a piece of bone from its attachment site, known as an avulsion fracture.
Symptoms
The PIP joint may feel painful and swollen, and you may be unable to straighten it. The DIP joint may become hyperextended, making the finger look crooked.
Diagnosis
Doctors can diagnose boutonniere deformity by examining the hand. X-rays may be used to check for fractures and assess joint health.
Treatment
In some cases, splinting can treat boutonniere deformities, addressing both new and old injuries. Different splint types are available, and hand therapy is crucial for symptom relief and functional improvement. Splinting typically lasts for at least six weeks.
Surgery
Surgery might be needed to repair or reconstruct the tendon or joint. If treatments fail, finger bones may be fused to prevent movement. All surgeries are followed by splinting and hand therapy.
Recovery
Recovery from surgery may take three to four months, with full recovery potentially lasting up to six months. Your doctor will provide a personalized recovery plan based on your condition.
Prevention
If you notice signs of boutonniere deformity, consult your doctor right away. Early treatment is often linked to the best outcomes. Your hand therapist can provide advice on how to perform daily activities safely to prevent future injuries.
