Boutonniere Deformity: Symptoms, Types, Causes and Treatment

Boutonniere deformity is a distinct finger or thumb abnormality that can significantly impact hand function and quality of life. Recognizing its symptoms, understanding the different types, unraveling its causes, and being aware of the latest treatment options are crucial for patients and healthcare providers alike. This comprehensive article synthesizes current research to provide an authoritative overview of boutonniere deformity, empowering readers with evidence-based insights and practical information.

Symptoms of Boutonniere Deformity

Boutonniere deformity is most readily identified by its characteristic finger or thumb posture, but its clinical presentation extends beyond the visible deformity. Early recognition of its symptoms can lead to more effective management and better outcomes. Let’s explore what to look for.

Symptom	Description	Impact	Source(s)
Flexed PIP	Proximal interphalangeal (PIP) joint bent down	Limits finger straightening	2 3 6 13
Hyperextended DIP	Distal interphalangeal (DIP) joint bent back	Causes awkward finger posture	2 6 14
Thumb Deformity	Extension at MCP, flexion at IP in thumb	Affects thumb grasp	1
Reduced Motion	Loss of active PIP extension, limited grip	Hinders daily activities	3 6 13 14

Table 1: Key Symptoms

Detailed Explanation of Symptoms

Flexion at the PIP Joint

The hallmark of boutonniere deformity is a persistent flexion of the finger’s PIP joint. This means the middle joint of the affected finger is bent toward the palm and cannot be straightened actively. This posture arises from disruption to the central slip of the extensor mechanism, which normally straightens the finger at the PIP joint 2 3 6.

Hyperextension at the DIP Joint

While the PIP joint is flexed, the DIP joint (the one closest to the fingertip) is often hyperextended. This results in a “buttonhole” appearance—hence the name “boutonniere,” French for buttonhole 6 14. This imbalance disturbs the normal motion of the finger, making it difficult to perform precise tasks.

Thumb-Specific Deformity

In the thumb, boutonniere deformity presents as a flexed interphalangeal (IP) joint and hyperextended metacarpophalangeal (MCP) joint. This unique pattern reflects the thumb's anatomy and can impair pinching or grasping functions 1.

Reduced Motion and Function

Patients may notice a progressive loss of the ability to extend the finger at the PIP joint, making tasks such as grasping, typing, or buttoning clothes challenging. Chronic cases may also present with stiffness, pain, or swelling—especially if underlying conditions like rheumatoid arthritis are present 3 6 13 14.

Types of Boutonniere Deformity

Boutonniere deformity isn’t a one-size-fits-all condition. Its presentation and severity can vary, and understanding the different types is key to choosing the right treatment approach.

Type	Description	Correction Feasibility	Source(s)
Early	Passively correctable, flexible deformity	Fully correctable	1 3 13
Moderate	Some stiffness, passively correctable, joint involved	Partially correctable	1 13
Advanced	Fixed deformity, joint changes, loss of flexibility	Not correctable	1 7 13 14
Chronic	Present for >6-8 weeks, may be fixed or flexible	Variable	3 6 14

Table 2: Types of Boutonniere Deformity

In-Depth Exploration of Types

Early (Flexible) Deformity

Early boutonniere deformity is characterized by a flexible posture. The PIP joint can be straightened with gentle pressure, indicating that the deformity is not yet fixed. This stage responds best to non-surgical treatments such as splinting or relative motion orthoses 1 3 13.

Moderate Deformity

At this stage, the deformity becomes less flexible. Although some passive correction is still possible, joint involvement and soft tissue changes make management more challenging. Surgical interventions may be considered, especially if function is deteriorating 1 13.

Advanced (Fixed) Deformity

Advanced boutonniere deformity involves a fixed contracture of the PIP joint. The joint can no longer be straightened, even with force. This stage is often accompanied by degenerative changes in the joint and surrounding tissues, and surgical options—such as joint fusion or arthroplasty—may be necessary 1 7 13 14.

Chronic Deformity

A deformity is considered chronic when it persists for more than 6–8 weeks. Chronic cases may be fixed or still partly flexible. Treatment strategies depend on the chronicity and the degree of joint involvement, with options ranging from serial casting and splinting to reconstructive surgery 3 6 14.

Causes of Boutonniere Deformity

Understanding the mechanisms behind boutonniere deformity is crucial for prevention and targeted treatment. The condition can arise from several distinct pathways, all converging on disruption of the finger’s extensor mechanism.

Cause	Mechanism/Description	Commonality	Source(s)
Central Slip Injury	Rupture/tear of central slip of extensor tendon	Most common	2 3 9
Rheumatoid Arthritis	Chronic synovitis weakens extensor mechanism	Frequent in RA	1 7 13
Trauma	Laceration, crush, or dislocation injuries	Varied	9 12
Burns	Damage to tendons and soft tissue	In burn victims	4 11
Dupuytren’s Disease	Fibrous contraction displaces extensor apparatus	Rare	8

Table 3: Causes of Boutonniere Deformity

Exploring the Underlying Causes

Central Slip Injury

The most common direct cause is a rupture or avulsion of the central slip of the extensor tendon over the PIP joint. This injury prevents the finger from straightening at the PIP joint, and if untreated, the lateral bands of the extensor mechanism slip to the sides and below the axis of the joint, reinforcing the deformity 2 3 9. Notably, injury to the central slip alone may not cause the full deformity; damage to other supporting structures (triangular ligament, interosseous hood) is often necessary for the classic boutonniere posture to develop 2.

Rheumatoid Arthritis

Chronic synovitis and inflammation in rheumatoid arthritis can weaken and stretch the extensor mechanism, leading to progressive boutonniere deformity. Synovial proliferation may erode the central slip and surrounding ligaments, undermining joint stability 1 7 13. In the thumb, rheumatoid changes produce a similar, though anatomically distinct, boutonniere pattern 1.

Traumatic Injuries

Direct trauma, such as lacerations, crush injuries, or dislocations, can disrupt the central slip or lateral bands. Post-traumatic boutonniere deformity may also develop after closed injuries (e.g., forced flexion of an extended finger), and in rare cases, following dislocations in the toes 9 12.

Burns

Severe burns can damage the dorsal extensor apparatus and lead to scarring, contracture, and subsequent boutonniere deformity—especially if healing is complicated by tendon adhesions or soft tissue loss 4 11.

Dupuytren’s Disease

Boutonniere deformity may rarely occur as a complication of Dupuytren’s disease, due to fibrous thickening and contracture of the transverse retinacular ligament, which pulls the extensor mechanism out of alignment 8.

Treatment of Boutonniere Deformity

Effective treatment of boutonniere deformity hinges on early diagnosis and tailoring interventions to the deformity’s type and underlying cause. Therapies range from conservative splinting to advanced surgical reconstruction, with promising results from newer, less invasive techniques.

Treatment Modality	Indication/Stage	Key Features	Source(s)
Splinting/Orthosis	Early, flexible, or some chronic cases	Non-invasive, preserves function	3 5 13
Serial Casting	Chronic, fixed but passively correctable	Gradual correction	3
Relative Motion Splint	Acute and chronic, preserves hand use	Allows early motion, low morbidity	3
Surgical Repair	Moderate/advanced, failed conservative	Various reconstructive techniques	1 7 12 14
Tendon Grafts	Chronic, lateral bands deficient	e.g., palmaris longus autograft	14
Joint Fusion/Arthroplasty	Advanced, fixed deformity, arthritis	Restores alignment, sacrifices some motion	1 7 13

Table 4: Treatment Options

Modern Approaches to Treatment

Non-Surgical Management

• Splinting and Orthoses: Early-stage boutonniere deformity responds well to splinting, which holds the PIP joint in extension while allowing movement at the DIP joint. This can be achieved with static or dynamic splints and is often combined with hand therapy 3 5 13.
• Relative Motion Splinting: A newer approach, relative motion flexion orthosis, positions the injured finger in slightly more MCP flexion than adjacent digits, permitting early active movement and functional use of the hand during healing. This approach has shown excellent results, even in chronic cases, with minimal morbidity and no need for extended therapy after splinting 3.
• Serial Casting: In chronic, fixed deformities that remain somewhat flexible, serial casting can gradually restore extension at the PIP joint before transitioning to orthosis-based therapy 3.

Surgical Treatment

• Direct Tendon Repair: For acute injuries with torn central slips, surgical repair may be necessary if non-surgical approaches fail 12.
• Reconstructive Surgery: For chronic or severe deformities, reconstructive techniques aim to restore the anatomy of the extensor mechanism. Options include staged release of contracted ligaments, tendon transfers, and repair or reconstruction of the central slip and lateral bands 12 14.
• Tendon Grafting: When lateral bands are irreparably damaged, tendon autografts (e.g., palmaris longus) can be used to reconstruct the extensor mechanism, offering good functional recovery 14.
• Joint Fusion or Arthroplasty: In advanced, fixed deformities with joint destruction (often due to rheumatoid arthritis), fusion (arthrodesis) of the PIP joint or joint replacement (arthroplasty) may be necessary to restore alignment and function, albeit with some loss of motion 1 7 13.

Special Considerations

• Postburn Deformity: Surgical repositioning of the lateral bands and reconstruction of the central slip can restore mobility in most burn-related cases, with soft tissue coverage as needed 11.
• Rheumatoid Thumb: Treatment choice depends on the stage; early cases may be managed with synovectomy and tendon rerouting, but moderate and advanced cases often require fusion or arthroplasty 1.

Conclusion

Boutonniere deformity is a complex condition with significant functional implications. Early recognition, precise diagnosis, and tailored management are critical for optimal outcomes. Here’s a quick summary of the key points:

• Symptoms: Characterized by a flexed PIP joint and hyperextended DIP joint, leading to loss of finger extension and functional impairment.
• Types: Ranges from early, flexible deformity to advanced, fixed contractures; chronic cases may be flexible or fixed.
• Causes: Most commonly due to injury to the central slip of the extensor tendon, but also associated with rheumatoid arthritis, trauma, burns, and, rarely, Dupuytren’s disease.
• Treatment: Early cases respond well to splinting and relative motion orthoses; chronic and advanced cases may require surgical reconstruction or joint fusion; tendon grafts and staged repair techniques offer solutions for complex presentations.

By staying informed about the evolving landscape of boutonniere deformity management, both patients and clinicians can work together to restore hand function and improve quality of life.