Stress fracture is a is caused by fatigue of the bone due to repeated stress on the bone over a period.
In contrast to fractures occuring as a single event of force acting to cause breakage of the bone, stress fractures result from accumulated trauma. The bone over a period then fails and fracture results.
For example, if a person begins running intensely without gradually training, it loads its bones and the bone is repeatedly loaded without being able to fully repair itself.
The fatigue accumulates and one day leads to failure of the bone.
Stress fractures typically appear as hairline fractures and occur mostly in weight bearing bones.
Stress fractures can be divided into fatigue and insufficiency fractures.
Fatigue fractures are the fractures that occur in normal bone that is abnormally loaded The abnormal stress could be in form of abnormal muscle stress, strenuous or repeated activity, a new or different activity, abnormal loading pattern of the bone or abnormal distribution of the stress.
A typical fatigue fracture patient is an active runner or somebody who abruptly started vigorous weight-bearing exercise . Classical description of the fatigue fracture use examples of military recruits and runners who have started vigorous running recently.
Common locations are metatarsals, upper and lower tibia, calcaneus, talus and proximal femur.
Insufficiency fracture results when normal stress is applied to abnormal bone and are most commonly seen in
- Osteoporosis
- Rheumatoid arthritis
- Paget’s disease
- Osteomalacia
Common locations include:
- Vertebrae
- Sacrum
- Neck of femur
- Pubic rami
- Sternum
Presentation
Typical symptom of stress fracture is pain which either begins or worsens with activity. The pain subsides with rest.
On examination, there would be tenderness in the area in question. In advanced cases swelling and redness may be found.
Athletes participating in tennis, track and field, gymnastics, and basketball are very susceptible to stress fractures due to repetitive stress of boot striking the ground.
Female athletes have been found to be more susceptible to stress fractures than their male counterparts.
Imaging
Radiographs
Xray remains the initial investigation for diagnosis though its sensitivity is very low at initial stage [15-35%].
There may be very subtle findings like lucencies or focal areas of sclerosis. In the later stage fracture line may be better appreciated.
If there is a strong clinical suspicion but a negative xray, additional investigation may be sought.
MRI
The most sensitive test to assess stress fractures. MRI can easily detect minor stress reactions. MRI also helps to differentiate stress fractures from malignant bone infiltrating lesions.
CT
Though it is less sensitive than MRI it is faster investigation and may be able to depict fracture pattern better.
Skeletal Scintigraphy
This used to be gold standard before MRI took over and is no longer done routinely. Three phase skeletal scintigraphy with technetium-99m (99m Tc) methylene diphosphonate hasan advantage that the entire skeleton can be screened.
Scintigraphic changes can be noted before plain film changes by up to a few weeks.
If xray is negative, in a routine clinical setting MRI is the investigation of choice.
Treatment
Rest is most important measure for treatment of the stress fractures.
Individuals need to take rest from the activity that is responsible for causing the stress fracture for six to eight weeks, time usually a stress fracture take to heal.
The activity should be resumed gradually after the rest other wise harder to heal stress fractures can develop.
Repeated injury might also lead to chronic condition where the stress fracture might never heal properly.
In addition to rest, shoe inserts or braces may be used to help these injuries heal. Analgesic amy be given as per need basis.
How To Prevent Stress Fracture
These tips are typically for fatigue stress fractures.
Graduate
When you participate in any new sports activity, set small incremental goals. One of the common cause of stress fractures is sudden increase in unaccustomed activity. For example do not get up and start running 5 kilometers a day, instead work towards the mileage gradually.
Cross Train
For example if you run every day, consider alternating between cycling and running. Add some strength training and flexibility exercises to the mix for the most benefit.
Diet
Maintain a healthy diet. Make sure you incorporate calcium- and Vitamin D-rich foods in your meals.
Equipment
You should always use proper equipment for your training.
Watch Out
If feel pain that worsens with the activity, immediately stop the activity and rest for a few days.
If the pain still persists, see an orthopedic surgeon.
