Stress fractures are either the result of abnormal stress placed on normal bone (fatigue fracture) or normal stress placed on abnormal bone (insufficiency fracture). The latter are seen in osteomalacia, rheumatoid arthritis, renal osteodystrophy, osteogenesis imperfecta, and Paget's disease. The former are classically seen in military recruits (march fracture) or weekend athletes, occurring in the tibia, calcaneus, or sacrum.
AP radiograph of the knee. There is a band of sclerosis through the proximal tibia. This represents a stress fracture.