Small bumps on your baby’s knees may be due to several reasons: 1. It may be a normal bony prominence. There are also bony prominences in the patella. For example, at the tip of the patella as well as in the middle and back of the patella, there are corresponding bony protrusions. At this time in the touch will often feel more pressure hand. 2, there may be localized cysts. This is often seen in front of the patella and above the patella, there is a local synovitis produced by the cysts, or in the tendon inside the small cysts. 3, there may be skin-related lesions, such as in the knee, if there is a mole on the skin surface, then feel like there is a small pimple. 4, it may also be due to old injuries caused by. For example, when the baby is crawling, if around the knee or violent collision, then it is possible to cause the soft tissues here to have a serious tonic injury, and then when it recovers, it may produce adhesions, scarring and other tissues, and thereafter it is possible to feel the swelling that protrudes from the skin surface.