**Core Concept**
Osgood-Schlatter disease is a common cause of knee pain in adolescents, characterized by inflammation of the patellar ligament at the tibial tubercle. This condition is typically seen in active, skeletally immature individuals.

**Why the Correct Answer is Right**
The disease is caused by repetitive traction on the patellar ligament, which is a tendinous structure connecting the patella to the tibia. The repetitive stress on this ligament leads to inflammation, pain, and swelling at the site of the tibial tubercle. This condition is often seen in individuals participating in sports that involve running, jumping, or other high-impact activities.

**Why Each Wrong Option is Incorrect**
**Option A:** Osgood-Schlatter disease is not caused by a bacterial infection, which is more commonly associated with conditions such as osteomyelitis.
**Option B:** While Osgood-Schlatter disease can cause knee pain, it is not primarily a condition of the meniscus, which is a cartilaginous structure that cushions the joint.
**Option C:** Osgood-Schlatter disease is not a condition of the hip joint, but rather a condition affecting the knee.
**Option D:** Osgood-Schlatter disease is not a type of osteochondritis dissecans, which is a condition where a piece of cartilage and bone becomes detached from the surrounding bone.

**Clinical Pearl / High-Yield Fact**
Osgood-Schlatter disease is more common in boys than girls, and typically affects individuals between the ages of 10 and 15. It is often associated with overuse or repetitive stress on the knee joint.

**Correct Answer: C. Osgood-Schlatter disease is a condition of the knee joint, characterized by inflammation of the patellar ligament at the tibial tubercle.**