A new radiographic method of measuring carpal collapse

Area of Science:

• Orthopedic Surgery
• Radiology
• Biomechanics

Background:

• Carpal collapse is a significant indicator of wrist instability.
• Accurate diagnostic methods are crucial for timely intervention.
• Existing methods like revised carpal height (RCH) may lack sufficient diagnostic power.

Purpose of the Study:

• To validate the diagnostic accuracy of the capitate-radius (CR) index for assessing carpal collapse.
• To compare the efficacy of the CR index against the revised carpal height (RCH) method.
• To establish reference values for the CR index in normal wrists.

Main Methods:

• Measurement of the capitate-radius (CR) distance on standard plain radiographs.
• Comparison of CR index with the revised carpal height (RCH) method in normal subjects and patients with Kienböck's disease.
• Utilizing Receiver Operating Characteristic (ROC) curves to evaluate diagnostic accuracy.

Main Results:

• A significant difference was observed in the left/right CR index between normal wrists and those with Kienböck's disease (p < 0.001).
• The left/right RCH index showed no significant difference (p = 0.30).
• The CR index demonstrated higher diagnostic accuracy compared to the RCH index based on ROC curve analysis.

Conclusions:

• The capitate-radius (CR) index is a reliable and accurate radiographic method for diagnosing unilateral carpal collapse.
• The CR index can be effectively used for monitoring disease progression in bilateral carpal collapse.
• A CR index value less than 0.92 is suggested as abnormal, with a mean value of 0.999 +/- 0.034 in normal wrists.