2002 OITE Question 4

Question

When treating a distal radius fracture by closed reduction and external fixation, palmar tilt can be restored by combining longitudinal traction with

1- wrist flexion.

2- wrist extension.

3- volar shift of the carpus.

4- forearm supination.

5- forearm pronation.

Figures

Answer (click for answer)

Correct Answer: 3- volar shift of the carpus.

This is one of Dr. Zelouf’s favorite points in fracture conference. The referenced article is by John Agee and basically describes the biomechanics of the distal radius fracture. This has been subsequently incorporated into Agee’s commercially available wrist jack. In the case of the dorsally displaced distal radius fracture, the article demonstrates that two separate and distinct types of ligamentotaxis are required for reduction. The first involves longitudinal traction, which typically restores length and improves appositional and angular alignment. However, at this point the distal fragment is still tilted dorsally. A palmar translating force of the midcarpal joint (volar shift) is needed to tilt the distal radial fragment palmarly. The article points out that palmar tilt can actually also be obtained with wrist flexion; however, adequate reduction is only achievable and can only be maintained at the extremes of wrist flexion. Maintaining such a position until healing would result in a much compromised hand. Therefore, longitudinal traction with volar shift of the carpus is the better way to reduce this fracture.

Reference: Orthop Clin North Am 1993;24:265-274.