Stress fracture
A stress fracture or break, is the partial or incomplete fracture of a bone that results from 'repetitive 'stress' applied to a localized area of the bone.
Stress fractures are not fractures that take place because of one single event of damage, but instead is due to an accumulation of events (overuse injuries).
Stress fractures are not fractures that take place because of one single event of damage, but instead is due to an accumulation of events (overuse injuries).
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Accumulation of stress on the bones can lead to bone strain and micro-damages. In order to repair these damages the bone continually goes through a process of remodelling where old bones are replaced by new ones in order to optimize the structure according to present demands.
Remodelling starts with old bone removal and then proceeds to new bone formation, and starts almost as soon as damage occurs. The entire process takes approximately 2-8 months.
If there is an imbalance in damage generation and damage removal where the remodelling process isn’t given sufficient time to repair damages before applying more stress to the site, this would lead to an accumulation of damage and can ultimately result in stress fractures.
Causes and Risk Factors
Activities that increase the magnitude of applied stress or the frequency at which it occurs may contribute to the progression of a stress fracture.
Sports activity participation
Sports apply stress to the body; therefore regular participation in sports raises the risk of stress fractures. Stress fractures are very site-specific and occur in sites that are repeatedly exposed to a working load.
In running, sprinters, hurdlers and high- and long-jumpers apply a greater magnitude of the load to their feet more than middle and long-distance runners.
Long distance runners are at higher risk of getting stress fractures in areas such as the shinbone and pelvis because the load is applied repeatedly at high volumes in that area.
Changes in training regime
The remodelling process serves to enhance bone structure according to changes in mechanical demands.If there is insufficient time to adapt to an increased intensity in a training routine, the additional damage might take place.
Muscle fatigue
Muscles act as shock absorbers and help protect bones from stress fractures. If muscles are fatigued or weakened their ability to protect the skeleton is compromised and there is an increased risk of stress fractures.
Flat Foot (pes planus) or high arch foot (pes cavus)
Feet with a high arch have less shock absorbing capacity, and so the applied force can be transmitted up the leg, putting those with high arches at risk of stress fractures in the shin and thigh bone.
Flat feet, in comparison, are more shock absorbing, and therefore stress fractures tend to be in the feet.
Physical fitness
Persons that have a long history of regular exercise have decreased incidence of stress fractures, (due to the increase in bone stiffness and hence bone resistance to damage).
Poor nutrition
Poor nutrition and deficient calorie intake have been found to increase the risk of stress fractures by negatively affecting bone turnover.
Other risk factors include smoking, increased alcohol intake and use of a poor training surface.
Symptoms
Diagnosis
Stress fractures should be considered for persons that have had a recent increase in physical activity, or increased rate of activity with limited rest.
Hop Test
Tuning Fork Method
Plain Radiography
Bone Scintigraphy
Magnetic Resonance Imaging (MRI)
Treatment and Recovery
Treatment should begin as soon as a stress fracture is suspected, as delayed treatment delays recovery.
Treatment can take 4 to 12 weeks or longer, depending on the injury.
Some fractures are at high risk of leading to other complications, including becoming complete fractures, such as the femur neck in the thighbone, the kneecap, the shinbone, the anklebone, the long bone in the foot.
Remodelling starts with old bone removal and then proceeds to new bone formation, and starts almost as soon as damage occurs. The entire process takes approximately 2-8 months.
If there is an imbalance in damage generation and damage removal where the remodelling process isn’t given sufficient time to repair damages before applying more stress to the site, this would lead to an accumulation of damage and can ultimately result in stress fractures.
Causes and Risk Factors
Activities that increase the magnitude of applied stress or the frequency at which it occurs may contribute to the progression of a stress fracture.
Sports activity participation
Sports apply stress to the body; therefore regular participation in sports raises the risk of stress fractures. Stress fractures are very site-specific and occur in sites that are repeatedly exposed to a working load.
In running, sprinters, hurdlers and high- and long-jumpers apply a greater magnitude of the load to their feet more than middle and long-distance runners.
Long distance runners are at higher risk of getting stress fractures in areas such as the shinbone and pelvis because the load is applied repeatedly at high volumes in that area.
Changes in training regime
The remodelling process serves to enhance bone structure according to changes in mechanical demands.If there is insufficient time to adapt to an increased intensity in a training routine, the additional damage might take place.
Muscle fatigue
Muscles act as shock absorbers and help protect bones from stress fractures. If muscles are fatigued or weakened their ability to protect the skeleton is compromised and there is an increased risk of stress fractures.
Flat Foot (pes planus) or high arch foot (pes cavus)
Feet with a high arch have less shock absorbing capacity, and so the applied force can be transmitted up the leg, putting those with high arches at risk of stress fractures in the shin and thigh bone.
Flat feet, in comparison, are more shock absorbing, and therefore stress fractures tend to be in the feet.
Physical fitness
Persons that have a long history of regular exercise have decreased incidence of stress fractures, (due to the increase in bone stiffness and hence bone resistance to damage).
Poor nutrition
Poor nutrition and deficient calorie intake have been found to increase the risk of stress fractures by negatively affecting bone turnover.
Other risk factors include smoking, increased alcohol intake and use of a poor training surface.
Symptoms
- Pain, which varies in location based on where the stress fracture occurs. Someone with a tibial (shinbone) fracture may have knee pains, while someone with a pelvic fracture may have groin pains. Pain with movement is very common.
- Localized tenderness of the affected area until inflammation or activity has been stopped
- Edema (collection of watery fluid in body tissues and cavities) around the affected area.
- Possible bruising of the surrounding area
Diagnosis
Stress fractures should be considered for persons that have had a recent increase in physical activity, or increased rate of activity with limited rest.
Hop Test
Tuning Fork Method
Plain Radiography
Bone Scintigraphy
Magnetic Resonance Imaging (MRI)
Treatment and Recovery
Treatment should begin as soon as a stress fracture is suspected, as delayed treatment delays recovery.
Treatment can take 4 to 12 weeks or longer, depending on the injury.
- Restrict activity to the point where there is no pain. The RICE principle can be applied.
- Pain killers and non-steroidal anti-inflammatory drugs may be prescribed for pain control, (however, anti-inflammatory drugs should be used with caution, as these drugs may inhibit fracture healing).
- The use of crutches, stirrup leg braces may relieve pain and help with recovery time.
- To maintain flexibility, strength and physical fitness, physical therapy and cross training that will not aggravate the affected area during the recovery period may be considered.
- Surgery is another treatment option.
Some fractures are at high risk of leading to other complications, including becoming complete fractures, such as the femur neck in the thighbone, the kneecap, the shinbone, the anklebone, the long bone in the foot.