**Core Concept**
In pediatric orthopedics, the management of suspected fractures in young children requires careful consideration of their unique anatomy and physiology. The growth plates in children's bones are more susceptible to injury and may be affected differently than in adults.

**Why the Correct Answer is Right**
The correct approach for a suspected medial epicondylar fracture in a 4-year-old child involves immobilization to prevent further injury and promote healing. This is because children's bones have growth plates that are still open, and excessive movement can disrupt the healing process and lead to growth disturbances. Immobilization with a cast or splint helps to maintain the reduction and prevent further injury.

**Why Each Wrong Option is Incorrect**
**Option A:** Reduction and percutaneous pinning are not typically recommended for medial epicondylar fractures in young children due to the risk of growth plate damage and the potential for complications.

**Option B:** MRI is not the initial imaging modality of choice for suspected fractures in children, as it is not as readily available as X-rays and may not provide sufficient information to guide treatment.

**Option C:** Open reduction and internal fixation are typically reserved for more complex fractures or those that are not amenable to closed reduction and immobilization.

**Clinical Pearl / High-Yield Fact**
In pediatric orthopedics, it's essential to remember that the management of fractures in young children often involves a more conservative approach than in adults, with a focus on minimizing the risk of growth disturbances and promoting healing.

**Correct Answer: C. Open reduction and internal fixation are typically reserved for more complex fractures or those that are not amenable to closed reduction and immobilization.