MRI: Magnetic Resonance Imaging.
Orthopedic: Orthopedics is a branch of medicine, which is related to diagnosis and treatment of diseases of Musculoskeletal system.
Osteoclasts: A cell that breaks down unwanted bone tissue; also refers to a device for fracturing a bone to correct a deformity.
PET: Positron emission tomography scan. A computerized image of the metabolic activity of the body tissues used to determine the presence of disease.