[Deformities of the finger joints]

Area of Science:

• Hand surgery
• Orthopedics
• Rehabilitative medicine

Background:

• Finger extension is a complex biomechanical process.
• Boutonnière deformity involves proximal interphalangeal (PIP) joint flexion and distal interphalangeal (DIP) joint hyperextension, caused by central slip disruption.
• Swan neck deformity features PIP joint hyperextension and DIP joint flexion, with intrinsic, extrinsic, and articular origins.

Purpose of the Study:

• To define and differentiate Boutonnière and swan neck deformities.
• To outline the underlying pathologies of these finger deformities.
• To discuss treatment considerations and the importance of realistic outcome assessment.

Main Methods:

• Review of anatomical and biomechanical principles of finger extension.
• Classification of swan neck deformity based on etiological factors (intrinsic, extrinsic, articular).
• Analysis of treatment modalities, encompassing both surgical and non-operative options.

Main Results:

• Deformities result from imbalances in finger tendons and ligaments.
• Treatment strategies are tailored to the specific underlying cause of the deformity.
• Successful management necessitates a clear understanding of potential functional gains versus associated risks.

Conclusions:

• Accurate diagnosis of finger deformities is crucial for effective treatment planning.
• A comprehensive approach considering the etiology is essential for managing Boutonnière and swan neck deformities.
• Realistic evaluation of functional outcomes and risks is paramount in patient management.