A stress fracture is a small crack in a bone that initially does not show up on x-ray until they start to heal.

They develop from a repetitive activity, usually high impact, from spending a whole day pounding the streets to distance runners increasing their frequency and duration of training too rapidly. When muscles are overtired (fatigued), they are no longer able to absorb the shock of repeated impacts. When this happens, the muscles transfer the stress to the bones, creating a small crack or fracture.

Most stress fractures occur in the weight-bearing bones of the foot and lower leg. The most common sites are the second and third metatarsals of the foot.

Abnormal foot function such as over-pronation can be an underlying cause of a stress fracture. Individuals with a rigid foot type or forefoot equinus are also at risk. A biomechanical assessment and video gait analysis is needed to identify any underlying biomechanics that can this exacerbate tissue stress.

Stress fractures can also occur with normal usage if bones have been weakened by osteoporosis or other disease. These fractures are often called “insufficiency fractures” because there isn’t enough bone to withstand the normal stress of daily use.

Symptoms
Gradual pain and swelling over and around the area which increases with activity and reduces with rest. The area is tender to touch and if ignored can and result in a complete fracture.

Treatment and Prevention
Most stress fractures will resolve in 2-4 weeks if identified early and rested sufficiently. Treatment is via a joint approach involving suitable footwear advice and possible the use of a simple insole or orthotic to off-load the area or to correct any underlying biomechanical issues that may have contributed to the injury.

Any activity either in the workplace or within sports which could be at fault must be considered and an altered training programme or work practice must be considered to prevent recurrence.