Question

A child with a left femur shaft fracture, managed by plating. Which of the following types of callus formation occurs?

• A. Creeping substitution
• B. Primary callus
• C. Secondary callus

Hint:

Primary callus formation occurs in fractures treated with rigid fixation, such as plating, allowing for direct bone healing without much secondary callus.

Answer 1

The Correct Option is B

In the context of bone healing, particularly with a femur shaft fracture managed by plating, understanding the type of callus formation is essential. The key factor here is the biomechanical stability provided by the plating. This stability significantly influences the type of callus formed.

Bone Healing Process:
Bones heal through a series of stages, starting with hematoma formation, followed by a soft callus, hard callus, and finally remodeling to restore the bone's normal structure. The type of callus formed depends on the stability of the fracture fixation.

Types of Callus Formation:

• Creeping Substitution: This is primarily associated with the internal reconstruction of bone, often seen in grafts, rather than fractures.
• Primary Callus: This occurs when a fracture has absolute stability, which is typically achieved with rigid fixation methods like plating. The bone heals directly through a process similar to intramembranous ossification without a significant cartilaginous phase.
• Secondary Callus: This type forms when there is relative stability at the fracture site, commonly seen with non-rigid fixation like casting or nailing. It involves an initial cartilaginous phase, followed by endochondral ossification.

Given the scenario of a child with a left femur shaft fracture managed by plating, the correct type of callus formation is Primary callus. This is due to the rigid stability provided by the plating, facilitating direct bone healing.