Weight-Bearing Computed Tomography Analysis of Scapholunate Ligament Injury

Area of Science:

• Orthopedics
• Radiology
• Biomechanics

Background:

• Scapholunate interosseous ligament (SLIL) injuries can cause dynamic carpal instability.
• Non-weight-bearing imaging may not detect subtle instabilities.
• Weight-bearing computed tomography (WBCT) offers a method to assess carpal alignment under physiologic load.

Purpose of the Study:

• To evaluate carpal position under physiologic load in healthy and SLIL-injured wrists using WBCT.
• To determine if WBCT can identify dynamic instabilities in SLIL injuries.

Main Methods:

• Ten healthy controls and 10 participants with SLIL injuries underwent WBCT.
• Imaging was performed in non-weight-bearing neutral, weight-bearing push-up bar (WBPUB), and forced wrist extension positions.
• Radiographic parameters including scapholunate interval, capitate radius index, and scapholunate angle were analyzed.

Main Results:

• In SLIL injuries, the capitate radius index decreased significantly under weight-bearing.
• The scapholunate angle significantly decreased in weight-bearing positions for both groups.
• WBCT revealed reduced dorsal scaphoid translation in SLIL-injured wrists in the WBPUB position.

Conclusions:

• WBCT can demonstrate reduction of the scaphoid in SLIL injuries under load.
• Both WBPUB and forced wrist extension WBCT positions showed significant reduction of the scapholunate angle.
• WBCT may help identify reducible SLIL pathology preoperatively and guide intraoperative reduction.