Certified Hand Therapist (CHT) Practice Exam

Which of the following best describes Eaton classification type 3 for sprain/dislocations?

1. Complete tear between the accessory and proper collaterals

2. Fracture with dorsal dislocation and avulsed small fragment

3. Dorsal dislocation with complete destruction of articular surface

4. Dislocation without fracture

The correct answer is: Fracture with dorsal dislocation and avulsed small fragment

Eaton classification type 3 is characterized by a specific type of injury that involves both ligamentous injury and bone involvement. In this classification scheme, type 3 signifies a more severe injury that includes a fracture along with a dorsal dislocation. The presence of an avulsed small fragment indicates a fracture where a piece of bone has been pulled away by the ligament during the dislocation process. This type of injury often results in substantial instability within the joint as well as potential disruption of surrounding soft tissues, making it critical for assessment and treatment planning in rehabilitative therapy. The context of the other classifications provides a clearer contrast to type 3. For instance, type 1 would involve a sprain without dislocation or fracture, while type 2 may include more minor disruptions or sprains. Type 4 typically addresses complete dislocations without accompanying fractures, highlighting the nuances in ligament, bone, and joint stability found in the Eaton system. Understanding these distinctions is essential for developing effective treatment strategies and rehabilitation protocols.