There are various types of sports injuries that can occur around the hip and knee.
Injuries can occur to the soft tissues. For example, the muscles, tendons and ligaments. In the hip this could be gluteal tendonitis. In the knee, there could be a ligament sprain.
Injuries can occur to the bone such as bruising or stress fractures. In the hip, stress fractures can occur in runners for example.
Damage can occur to the articular cartilage surface lining the joints. This can cause early arthritis.