Fractional Dolphin Tenotomy for Boutonniere Deformity: A Cadaveric Study

Area of Science:

• Orthopedic Surgery
• Hand Surgery
• Reconstructive Surgery

Background:

• Chronic boutonniere deformity often involves distal interphalangeal (DIP) joint hyperextension.
• Terminal extensor tenotomy, or Dolphin tenotomy, is a recognized treatment approach.

Purpose of the Study:

• To evaluate the efficacy of incremental partial Dolphin tenotomy in correcting DIP joint hyperextension.
• To assess the risk of iatrogenic mallet finger formation with this technique.

Main Methods:

• A boutonniere deformity model was created in 38 cadaveric fingers.
• Incremental fractional terminal extensor tenotomy was performed (one-third, one-half, two-thirds, complete).
• DIP and proximal interphalangeal (PIP) joint positions were measured after each tenotomy step.

Main Results:

• DIP joint hyperextension improved incrementally with increasing tenotomy fractions (one-third, one-half, two-thirds).
• Complete tenotomy resulted in a significant extensor lag (25°).
• No iatrogenic mallet finger occurred with fractional tenotomy up to two-thirds.

Conclusions:

• Fractional terminal extensor tenotomy offers a graded approach to correct DIP joint hyperextension in boutonniere deformity.
• This technique may be suitable for patients with mild PIP joint involvement and primary DIP hyperextension.
• Tailoring the tenotomy extent allows for precise correction of the preoperative deformity.