Effect of wrist position on extensor mechanism after disruption separation

Area of Science:

• Orthopedic surgery
• Hand surgery
• Anatomy

Background:

• Extensor tendon injuries in zones I (DIP joint) and III (PIP joint) can lead to tendon separation and functional deficits.
• Understanding tendon excursion and gap formation is crucial for effective treatment.

Purpose of the Study:

• To evaluate extensor tendon separation and excursion following zone I and III lacerations.
• To determine optimal splinting positions to minimize tendon gaps and improve outcomes.

Main Methods:

• A cadaveric study was conducted on extensor tendon injuries at the DIP and PIP joint levels.
• Tendon gap and joint lag were measured after simulated lacerations.
• The effect of various splinting positions on tendon separation was assessed.

Main Results:

• Lacerations at the DIP joint resulted in an average 1.5 mm gap and 30 degrees lag.
• PIP joint lacerations showed an average 1.1 mm gap and 18 degrees extension loss.
• Splinting the DIP joint in 5 degrees hyperextension and the PIP joint in 0 degrees extension eliminated gaps in most positions.
• Wrist and metacarpophalangeal joint flexion increased tendon gaps.
• Wrist extension effectively eliminated tendon gaps.

Conclusions:

• Splinting zone I and III extensor tendon injuries with the injured joint in full extension is effective in minimizing tendon separation.
• Incorporating neutral to mild wrist extension in splinting protocols may optimize treatment for extensor tendon injuries.
• Allowing other joints to move freely while immobilizing the injured joint and wrist can enhance functional recovery.