Signs of a stress fracture in the Foot
Unlike a typical fracture where there is a clear break in the bone, a stress fracture is progressively developed from repetitively exerting the accustomed level of impact on a bone. For a variety of reasons the bone is unable to adapt to the mechanical load, and cannot heal between activities.
Historically noted for over 100 years in military recruits caused from marching, it has now become increasingly common in the non-military population. This is believed to coincide with the increase in levels of high impact sport and exercise people participate in. Professional athletes who run or jump are also at an increased risk of these injuries.
There are several factors involved in developing a stress fracture:
- Bone properties:Bone density, geometry and microarchitecture
- Mechanostat:The sensory system of bone detecting strain and activating an adaptive biological response
- Functional Stimuli:Mechanical, physiological, and pharmacological
- Constraints:Genetics, age, sex, nutrition
In clinic I see stress fractures that seem to be mainly attributable to levels of activity such as long distance running, problematic gait mechanics and foot structures. Usually these factors are in addition to a sudden increase in levels of activity. It is also common to see them related to poor footwear, and insufficient bone density – such as having osteoporosis.
Common areas of the foot:
- Heel:Some people heel strike when running but normally we all heel strike when walking. This is a repetitive function, and insufficient cushioning when walking long distances on hard surfaces will increase heel bone stress.
- Metatarsals: 2nd and 3rd are the most common:
If you have a short 1st metatarsal or long 2nd, mechanically you are likely to overload the head of the 2nd metatarsal which increases your risk of stress fracture. As often reported in the press, footballers frequently fracture these bones.
- Gradual onset of pain on weight bearing but improved when resting
- Mild swelling around a bone and sometimes warmer to touch
- Pain when the bone is squeezed
Investigation & treatment:
Stress fractures will usually not be obvious on X-ray in the early stages despite symptoms. Usually, it takes several weeks for signs to show using this method. They will however, be more likely spotted using MRI.
Bones take 6-8 weeks on average to heal and depending on the severity of the stress fracture, treatments tend to include:
- Refrain from running and reduce impacting activities
- Use of cushioned running shoes for shock absorbency
- Air cast boot
- Use of crutches
Once symptoms have disappeared then a slow and gradual return to activities is advised. On occasions, the fracture will not heal and surgical intervention is required to unite the bone with fixation during the healing process.
- Ensure you have sufficient vitamin D and calcium intake which are essential for bone health. Exposing your skin to sunlight, eating fatty fish and taking vitamin D supplements will increase your Vit D intake. Foods high in calcium: milk, kale, sardines, yoghurt, and cheese.
- Good footwear to offer sufficient cushioning relating to your activity levels. Replace trainers if they have lost their shock absorbency. Avoid thin soled shoes such as ballet pumps if you walk distances.
- Keep your weight down to reduce stress on bones. Speak to your GP or a dietician if you have trouble keeping your weight down or intaking a balanced diet.
- Vary activities and increase levels of activity gradually to allow your body to adapt. Changing surfaces will also help. Elliptical trainers and swimming have lower impact on your bones.
- See a specialist musculoskeletal podiatrist for an assessment of your foot, gait pattern and footwear.
Steven Thomas, Senior Podiatrist