BOUTONNIERE DEFORMITY and

SWAN NECK DEFORMITYBy Team III:

MJ/DW/NA/DB

ANATOMY

• Boutonniere deformity : the finger postures in PIP flexion and DIP hyperextension

• Boutennire → button hole → head of proximal phalanx button hole throght extensor hood secondary to rupture central slip

ETIOLOGY

• Direct trauma or rheumatoid disease• The injury may be open or closed.

PATHOLOGY

• Disruption of the central slip of the extensor tendon

• Lateral bands (LB) to slip volar to the PIP joint axis of motion → flexor forces on the PIP joint.

• The imbalance results → hyperextension DIP joint.

• The oblique retinacular ligament (ORL) of Landsmeer, which is located at the dorsal DIP joint → tight.

CLINICAL

• In anyone with tenderness or a cut over the dorsum of the PIP joint, especially if they cannot actively extend the IP joint with the MCP joints and wrist flexed.

• Elson’s test → determine possible tear the central slip before the deformity evident

CLASSIFICATION

• Mild → PIP joint lag of 10⁰ - 15⁰ in extension• Moderate → PIP joint lag of 30⁰ - 40⁰ in

extension• Severe → PIP joint in fixed flexed postion with

joint involment

Treatment Options for Boutonniýre Deformity of the Finger

Stage PIP Joint DIP Joint

I—Mild Dynamic splinting Extensor tenotomy

Injection vs synovectomy

II—Moderate Correct any wrist flexion first Extensor tenotomy

Extensor reconstruction

III—Severe Fusion (standard) Extensor tenotomy

Arthroplasty

SWAN NECK DEFORMITY

ANATOMY• Swan neck deformity → The finger postures

with PIP hyperextension and DIP flexion • The middle phalanx tends to be flexed, and the

finger appears to zigzag when observed from the side. The IP joints may be passively correctable, or they may be fixed in their deformity positions. The IP positions in the swan neck deformity are the opposite of their positions in the boutonnieredeformity.

ETIOLOGY

• Intrinsic tightness secondary to MCP joint disease

• Intrinsic contracture • FDS rupture• Volar plate insuffisiency• Mallet deformity• Extrinsic spastycity

PATHOLOGY

• The swan neck deformity can be caused by injuries at the level of the DIP, the PIP, or the MP joint.

• DIP level, a mallet injury can lead to swan neck deformity.

• The terminal extensor tendon is disrupted. This allows the extensor force to be more powerful proximally at the PIP joint, leading to PIP hyperextension.

• At the PIP level, the volar capsule is involved, with hyperextension at the PIP joint.

• The losse body are dorsally displaced, contributing to PIP hyperextension; this minimizes the pull on the terminal extensor tendon; therefore, the DIP joint assumes a flexed position. Normally the FDS helps deter PIP hyperextension.

• However, if the FDS has been ruptured or lengthened, PIP hyperextension forces are less restricted or controlled. Intrinsic muscle tightness compounds the problem.

• Painful snapping may be noticed with active flexion. This snapping is caused by the losse bodyvat the proximal phalanx condyles.

• MP level, MP volar subluxation and ulnar drift may be the initiating factors, as is seen in rheumatoid arthritis.

• The MP joint disturbance leads to intrinsic muscle imbalance and tightness, with resulting PIP hyperextension forces.

CLASSIFICATION (Nalebbuff types)

1. Flexible hyperextension deformity of the PIP joint

2. PIP joint flexion is limited when the MCP joint is maintained in extension. Intrinsic muscle tightness is present

3. Limited PIP joint flexion in all MCP joint positions, but the PIP joint surface is still preserved

4. PIP joint is stiff and there is destruction of the articular surface of the joint

Treatment Options for Swan Neck Deformity in Fingers

Type MP Joint PIP Joint DIP JointI Splint Fusion Dermadesis FDS sling

Littler's ORL reconstruction

II Intrinsic release As for type I FusionIII As for type II As for type II Fusion

MP joint reconstruction as needed

PIP joint manipulation

Skin release

Lateral band mobilization

Check flexor tendons IV As for type III As for type III Fusion Arthroplasty Fusion

THANK YOU