**Question:** Fracture lateral condyle of the humerus is a common injury in children. Which one of the following is the most ideal treatment for a displaced fracture lateral condyle of the humerus in a 7-year-old child?

A. Plaster cast
B. Intramedullary pin fixation
C. Reduction and external fixation
D. Open reduction and internal fixation

**Correct Answer:**

**Core Concept:**
Lateral condyle fractures are common in pediatric patients, particularly those aged between 5-10 years. These fractures are typically non-displaced or minimally displaced, and the treatment primarily focuses on reducing the fracture and immobilizing it to allow for proper healing.

**Why the Correct Answer is Right:**
The most ideal treatment for a displaced fracture lateral condyle of the humerus in a 7-year-old child would be option C: Reduction and external fixation. In children, open reduction and internal fixation (option D) is not recommended due to the risk of damaging the growing periosteum, which could lead to malunion or non-union. Moreover, intramedullary pin fixation (option B) could potentially harm the growth plate and cause growth disturbances. On the other hand, a plaster cast (option A) may not provide sufficient stability for the fracture to heal properly, as it does not hold the fracture fragments in place effectively. External fixation, on the other hand, offers stable fixation, maintains the reduction, and allows for early motion of the elbow joint, promoting healing and preventing complications.

**Why Each Wrong Option is Incorrect:**

A. Plaster cast (Option A) is not the ideal choice for a displaced fracture as it does not provide sufficient stability to the fracture fragments, leading to a higher risk of malunion, non-union, or damage to the growth plate.

B. Intramedullary pin fixation (Option B) carries the risk of damaging the growth plate, which could result in growth disturbances.

C. Reduction and external fixation (Option C) is the best choice among the given options as it provides stable fixation, maintains the reduction, and allows for early motion of the elbow joint, promoting healing and preventing complications.

D. Open reduction and internal fixation (Option D) is not suitable for pediatric patients due to the risk of damaging the growing periosteum and causing malunion, non-union, or growth disturbances.

**Clinical Pearls:**

* Ensure to use a well-fitted cast or splint to immobilize the affected limb and protect it from further trauma.
* Early motion is essential for fracture healing in pediatric patients. External fixation allows for this, preventing complications associated with immobilization methods that limit joint motion.
* Growth plates in children's bones are vulnerable, so selecting the correct fixation method is crucial to prevent long-term complications.