Osteochondritis Dissecans: A type of osteochondritis in which articular cartilage and associated bone becomes partially or totally detached to form joint loose bodies. Affects mainly the knee, ankle, and elbow joints.Osteochondritis: Inflammation of a bone and its overlaying CARTILAGE.Joint Loose Bodies: Fibrous, bony, cartilaginous and osteocartilaginous fragments in a synovial joint. Major causes are osteochondritis dissecans, synovial chondromatosis, osteophytes, fractured articular surfaces and damaged menisci.Fractures, Cartilage: Breaks in CARTILAGE.Arthroscopy: Endoscopic examination, therapy and surgery of the joint.Elbow Joint: A hinge joint connecting the FOREARM to the ARM.Knee Joint: A synovial hinge connection formed between the bones of the FEMUR; TIBIA; and PATELLA.Bone Transplantation: The grafting of bone from a donor site to a recipient site.Osteochondrosis: Any of a group of bone disorders involving one or more ossification centers (EPIPHYSES). It is characterized by degeneration or NECROSIS followed by revascularization and reossification. Osteochondrosis often occurs in children causing varying degrees of discomfort or pain. There are many eponymic types for specific affected areas, such as tarsal navicular (Kohler disease) and tibial tuberosity (Osgood-Schlatter disease).Patella: The flat, triangular bone situated at the anterior part of the KNEE.Range of Motion, Articular: The distance and direction to which a bone joint can be extended. Range of motion is a function of the condition of the joints, muscles, and connective tissues involved. Joint flexibility can be improved through appropriate MUSCLE STRETCHING EXERCISES.Cartilage, Articular: A protective layer of firm, flexible cartilage over the articulating ends of bones. It provides a smooth surface for joint movement, protecting the ends of long bones from wear at points of contact.Femur: The longest and largest bone of the skeleton, it is situated between the hip and the knee.Transplantation, Autologous: Transplantation of an individual's own tissue from one site to another site.Chondrocytes: Polymorphic cells that form cartilage.