Certified Hand Therapist (CHT) Practice Exam

When does the repair phase of fracture healing typically occur?

1. From day 1 to day 5

2. From day 5 to day 21

3. From day 21 to 18 months

4. From day 0 to day 10

The correct answer is: From day 5 to day 21

The repair phase of fracture healing typically occurs from day 5 to day 21 after the initial injury. During this critical phase, the body begins to lay down a new bone matrix that replaces the initial soft callus formed in the inflammation phase. Biologically, this phase is characterized by the transformation of the soft callus, primarily made of fibrous tissue and cartilage, into a hard callus that will eventually become bone. This is a pivotal time when osteoblasts, the cells responsible for bone formation, actively proliferate and mineralize the newly formed matrix, leading to increased mechanical stability of the fracture site. Understanding the timing of this phase is essential for rehabilitation and therapeutic interventions. Applying mechanical loading too early can disrupt the healing process, while too much immobilization can hinder bone strength development. Thus, knowledge of the repair phase's time frame is critical in planning effective treatment strategies for patients recovering from fractures.