What is the most common cause of PIP dorsal dislocation?

The most common cause of proximal interphalangeal (PIP) dorsal dislocation is hyperextension with rupture of the volar plate. This injury occurs when the finger is subjected to a force that causes it to bend backward beyond its normal range of motion. The volar plate, a fibrous structure on the palm side of the PIP joint, stabilizes the joint and allows for smooth movement. When hyperextension occurs, it can lead to the rupture of this plate, resulting in the dislocation of the joint.

In cases of hyperextension, the bones in the joint can be forced apart, leading to a dorsal dislocation where the proximal phalanx is displaced towards the back of the hand. Understanding the mechanism of this injury is crucial for treatment, as it often requires specific interventions to restore joint stability and function. Meanwhile, while direct trauma to the finger may cause dislocations, it is less common than the mechanism of hyperextension involving the volar plate. Similarly, twisting of a semi-flexed phalanx and shearing forces may contribute to other types of finger injuries or dislocations but are not the primary causes of PIP dorsal dislocation.