A realistic and detailed educational animation with a sky-blue background. It clearly shows a transparent view of human leg muscles and bones. The camera zooms in on the kneecap, revealing a condition known as "osteoporosis," where the bone appears porous. Instantly, the holes in the bone are filled with golden particles, resulting in a full and healthy-looking kneecap. The animation features vibrant colors, a smooth 3D style, high detail, 4K resolution, and 30 frames per second.