Which condition is characterized by a painful bump below the knee that worsens with activity?

Osgood-Schlatter disease is a condition that typically occurs in adolescents who are active in sports. It is characterized by pain and swelling just below the knee, where the patellar tendon attaches to the tibial tuberosity. This area can become irritated and inflamed due to repetitive strain or stress, especially during activities such as running, jumping, or kicking. The pain often worsens with physical activity and improves with rest, making this condition distinct in its features and mechanisms.

The development of a painful bump in Osgood-Schlatter typically precedes physical activity, and the condition is more pronounced during periods of growth, particularly in young athletes. Understanding the biomechanical factors involved, such as the tension on the patellar tendon from quads and the impact of sports on the knee joint, helps clarify why this condition presents as it does.

In contrast, other conditions listed may cause knee pain but are associated with different symptoms or anatomical locations. For instance, patellar tendonitis is more associated with pain directly at the patellar tendon insertion rather than below the knee, while a posterior cruciate ligament injury would typically involve instability or swelling rather than a specific bump. Similarly, patellofemoral pain syndrome usually presents with anterior knee pain