Forearm Shortening Impact on Pronation and Supination.

Area of Science:

• Orthopedic surgery
• Biomechanics
• Anatomy

Background:

• Forearm shortening is a recognized treatment for severe limb trauma and nonunions.
• The specific impact of forearm shortening on rotational function remains incompletely understood.
• This study investigates how the location and extent of forearm shortening affect rotational capacity.

Purpose of the Study:

• To quantify the effect of forearm shortening location on rotational range of motion.
• To determine the relationship between the amount of shortening and rotational loss at different forearm levels.

Main Methods:

• Nine fresh cadaveric forearms were utilized, preserving proximal and distal radioulnar joints and the interosseous membrane.
• Peak interosseous distance (PID) and its level (PIDL) were measured.
• Progressive osteotomies were performed at 1 cm intervals in the distal, middle, and proximal thirds, with rotation measured after each step.

Main Results:

• Forearm rotation loss was greatest in the middle third (5.31°–6.12°/cm) and distal third (1.62°–2.20°/cm).
• Shortening up to 5 cm in the proximal third did not significantly affect forearm rotation.
• The average forearm rotation was 157°, with supination averaging 80° and pronation 77°.

Conclusions:

• Shortening in the middle and distal thirds of the forearm has a more detrimental effect on rotational function compared to the proximal third.
• These findings provide crucial biomechanical data for surgical planning involving forearm shortening procedures.