Stress Fractures

Stress fractures are a common injury often seen in military personnel and in athletes or anyone who is subjecting their feet or lower body to overuse. It most commonly occurs in the legs but can occur in other parts of the body. Typical areas for this type of fracture are the leg bones of the metatarsals, the fibula and tibia, with areas higher up the legs much less commonly affected. Stress fractures are caused by repeated stresses to the bone which are not enough to fracture initially, leading to mechanical fatigue of the bone and eventually a fracture.

The affected area may be the source of increasing pain levels during exercise and activity, with the sufferer often reporting they have increased their training levels in intensity or frequency. Conservative treatment is usually straightforward with limitation of activity of the part and in some fractures immobilisation is required. Healing is often also straightforward although there is the danger of non-union in some fractures, with some needing internal fixation. Orthopaedic fixation and careful immobilisation will lead to healing in the vast majority of cases.

These types of fractures occur because bone has been loaded again and again and there is rarely any specific traumatic event responsible for the fracture. Bones remodel to reinforce themselves when they are subjected to loads involving tension or compression, with minor damage of the bone occurring due to the stresses. If the remodelling process gets behind as the microscopic bone damage occurs then a fracture can result. The most common occurrence is for the person to have significantly increased their activities recently.

Risk factors for this injury include the elevation in how often the stresses occur, the raising of the strength of those stresses or a change in the tissue areas to which the forces are being applied. If the cross sectional area of bone which is being stressed is smaller then this will cause an increase in the stresses through that area, or the area can stay the same and the force be increased. Jumping and running are activities with a higher risk along with changes in the way activities are performed or the type of surface used.

Additional factors could be risk factors such as reduced bone density, dietary changes, weakness or other mechanical factors as the other factors are all mostly presumed to be the key ones. Scientific research has indicated being female, having a low body weight, poor diet and many other factors may be important. Female runners are particularly at risk, with reduced caloric intake, disturbances in menstrual cycle and lower bone density presenting in such athletes and others who require a low body weight such as ballet dancers.

The most common onset for a stress fracture is low profile and without high pain levels, typically following repeated bearing of weight on a part of the foot or leg and without any incident. The pain will resolve when the patient takes their weight off the part and re-occur when they once again repeat the typical movement. Local palpation of the injured areas may show oedema and pain or tenderness but there may be a lapse of between 2 and 4 weeks before a fracture can show up on an x-ray. Earlier detection of fractures may be possible with bone scanning.

Stress fractures are mostly treated with conservative methods, the most effective and the most straightforward being to limit the aggravating functional activity responsible for a period of four to six weeks. If weight bearing causes significant pain then it can be restricted by using elbow crutches with a rigid walking boot, brace or below knee plaster cast. Studies have been done on wearing corrective orthoses in shoes and there is some evidence they can reduce the incidence of stress fractures, with some potential benefits from shock absorbing insoles

Most commonly these fractures heal well and without complications but there can be problems with non-union in some particular areas. The base areas of the second and the fifth foot metatarsals are areas which can suffer from poor healing and which should be followed up for more prolonged immobilisation or surgical intervention if they do not heal.

Jonathan Blood Smyth is the Superintendent of Physiotherapy at an NHS hospital in the South-West of the UK. He writes articles about back pain, neck pain, and injury management. If you are looking for physiotherapists in Brighton visit his website.