**Core Concept**
Congenital coxa vara is a rare hip deformity characterized by a short, angled femoral neck, leading to limited hip abduction and external rotation. This condition arises due to an abnormality in the development of the proximal femur, specifically the femoral neck and head.

**Why the Correct Answer is Right**
The treatment of congenital coxa vara involves surgical correction to restore the normal anatomical alignment of the hip joint. This is typically achieved through a femoral osteotomy, where the femoral neck is cut and realigned to improve the hip's mechanical axis. The goal is to promote normal hip joint function, preventing future degenerative changes. The most common surgical procedure for coxa vara is a varus osteotomy of the proximal femur.

**Why Each Wrong Option is Incorrect**
* **Option A:** **Percutaneous pinning** is not a suitable treatment for congenital coxa vara, as it does not address the underlying anatomical deformity.
* **Option B:** **Hip replacement** is not indicated in congenital coxa vara, as the patient's age and condition do not justify a prosthetic joint.
* **Option C:** **Pavlik harness** is used to treat developmental dysplasia of the hip, not congenital coxa vara.

**Clinical Pearl / High-Yield Fact**
In cases of congenital coxa vara, early surgical intervention is crucial to prevent long-term complications, such as osteoarthritis and limited mobility.

**Correct Answer:** C. Varus osteotomy of the proximal femur.