Patients with a wide variety of orthopaedic disorders can be usefully investigated by nuclear medicine techniques, mostly by bone scintigraphy. Overall this area of nuclear medicine activity is increasing which is a trend that can be expected to continue. The principal conditions that are imaged are fractures and their sequelae, sports medicine injuries and osteomyelitis. However, there are many other orthopaedic problems that are appropriately investigated including biomechanical stress lesions, enthesopathies, avascular necrosis, some bone tumours, arthritidies, metabolic bone disease and nonaccidental injury. Single photon emission computed tomography (SPECT) has provided new indications for bone scintigraphy such as spondylolysis and facet syndrome in the lumbar spine, and meniscal tears in the knee. A role for positron emission tomography (PET) in orthopaedic nuclear medicine has yet to be identified but applications can be expected.