This is a common injury of the knee. Your knee joint is cushioned by two c-shaped wedges of cartilage called the "menisci." Each individual cushion is called a "meniscus." This injury is a tear of one of these cushions.
The rotator cuff is a group of muscles and tendons in each shoulder. It holds your upper arm bone in your shoulder socket. It keeps your arm stable while allowing it to lift and rotate. Too much stress on the rotator cuff can cause a tear. This can be a painful injury.