Stress or fatigue fractures are also due to overuse. With increased physical activity, bone is resorbed faster than it is replaced, resulting in weakening of the bone and microfractures. Ballet dancers are particularly prone to stress fractures at the base of the second metatarsal. These fractures are slow to heal given the unique position of the second metatarsal, which is countersunk into the tarsal bone. Radiographs and bone scans have been the diagnostic mainstays to date.
Bone scans are sensitive but nonspecific.
MRI can clearly demonstrate the spectrum of stress injury from stress response to a fracture. Inflammatory changes in the adjacent soft tissues are usually marked. The most common forms of coalition involve the talocalcaneal and calcaneonavicular joints. Each of these coalitions has an almost equal incidence. The restriction of motion caused by the coalition exerts stress loading on the adjacent joint.