Last Updated on February 12, 2025
A stress fracture is caused by fatigue of the bone due to repeated stress on the bone over a period. In contrast to fractures occurring 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, 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 may be the final stage of being divided into fatigue and insufficiency fractures.
Breithaupt first described stress fractures in the feet of Prussian soldiers in 1855. He called them march fractures. Nowadays, stress fractures are mostly seen in sportspersons, especially those participating in running, gymnastics, tennis, basketball, golf, and rowing. Jumpers, bowlers, and dancers present the greatest risk of injury to the lumbar spine and pelvis. Upper extremity stress fractures are rare but have been reported in gymnastics, weightlifting, and throwing sports.
These are commonly seen in
- Tibia
- Navicular
- Metatarsal
- Femur
- Fibula
- Ribs
- Pars interarticularis
- Lumbar vertebrae
- Pelvis
Stress fractures are more commonly seen in females.
Some stress fractures are more common in specific sports.
- Runners – tibia and metatarsal [ pelvic stress fractures in female runners]
- Long-distance running- femoral neck and pelvic injuries
- Hurdlers- patella fractures
- Gymnasts, soccer/rugby players, weightlifters- sondylolysis.
Pathophysiology
Osteocytes respond to biomechanical stress by secreting mediators that regulate osteoblast and osteoclast activity. Cyclic loading can cause the normal osteocyte signaling to be compromised and thus impede the physiological mechanisms of repair.
This may lead to the appearance of microfracture as there may not be sufficient tie to repair between the cycles. If this is not treated, it will evolve into complete fracturing of the bone affected.
Risk Factors for Stress Fractures
The risk factors could be extrinsic or intrinsic
Extrinsic factors
- Sports movements
- Nutritional habits
- Footwear and other sports equipment
- Terrain
- Training intensity
- Athlete’s fitness level
Intrinsic factors
- Anatomical variations like stiff foot, a discrepancy of the lower limbs, genu valgum
- Hormonal status
- Gender
- Age
- Decreased bone mineral density
- Low levels of physical and muscle conditioning
- Limitations of dorsiflexion due to shortening of the sural triceps
- Hyperpronation of the forefoot
Classification of Stress fractures
Fatigue and Insufficiency Fractures
Fatigue fractures are fractures that occur in the normal bone that is abnormally loaded The abnormal stress could be in the 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. The classical description of the fatigue fracture uses examples of military recruits and runners who have started vigorous running recently.
Metatarsals, upper and lower tibia, calcaneus, talus, and proximal femur are common locations.
Insufficiency fracture results when normal stress is applied to abnormal bone and is most commonly seen in
- Osteoporosis
- Rheumatoid arthritis
- Paget’s disease
- Osteomalacia
Common locations include:
-
- Vertebrae
- Sacrum
- Neck of femur
- Pubic rami
- Sternum
High-risk and Low-risk Stress fractures
A high-risk stress fracture is located in an area with a poor blood supply and often maximum tension force region of the bone. This makes it more prone to delayed healing, non-union, and potential complications. They can be difficult to diagnose and require a high index of suspicion. High-risk stress fractures include
- Femoral neck
- Anterior tibia,
- Navicular
- Talus
- Sesamoid bones
- 1st and 5th metatarsal
A low-risk stress fracture occurs in a location with better blood flow, allowing for faster healing and less risk of complications. A low-risk stress fracture can be seen in
- Posterior tibia
- 2nd to 4th metatarsals
- Femur
- Inferior and superior pubic rami
- Sacrum
- Fibula
Most low-risk stress fractures can be managed conservatively whereas high-risk stress fractures need aggressive management and quite often surgical intervention.
Clinical Presentation
Patients often present with an insidious onset of pain initially starting after the activity and subsiding after the activity. The pain progressively lasts longer and longer after a bout of exercise. Over a period, the residual pain without activity may appear to worsen or worsen with activity.
In the case of a sportsperson, details should be sought of recent changes in quality, intensity of training, and any changes in sports gear, etc. Extrinsic and intrinsic factors as discussed above should be sought.
On examination, the Patients typically have focal tenderness to palpation and occasional edema at the site of the suspected stress fracture.
Spondylolysis can remain asymptomatic and may be found incidentally on lumbar films. However, some athletes would complain of back pain that worsens with hyperextension.
Spondylolisthesis occurs when the pars defect does not heal, and there is a migration anterior of the vertebral body.
Lab Investigations
Lab investigations often are normal. Serum levels of calcium, phosphorus, creatinine, and 25(OH)D3 may be done to know about bone turnover and any deficiency of vitamin D that may lead to osteomalacia changes.
Nutritional markers may be done, especially in female athletes if there is weight loss and anorexia; along with hormone levels [FSH and estradiol] if there is amenorrhea or dysmenorrhea.
Imaging
Radiographs
X-rays may be normal in the initial stages. There may be very subtle findings like lucencies or focal areas of sclerosis. In the later stage, the fracture line may be better appreciated.
Therefore additional investigations should be done if x-rays are normal.
If there is a strong clinical suspicion but a negative x-ray, additional investigation may be sought.
CT
CT is inferior to MRI for stress fractures and should be done only if MRI is contraindicated. However, Chronic and quiescent lesions may be more evident with CT than MRI.
SPECT
Single-photon emission computerized tomography can detect early changes. It shows stress reactions of the bone before the fracture is seen on plain films. If SPECT is negative, the fracture is not likely.
Single photon emission CT (SPECT) has been particularly useful in spondylolysis.
Nuclear medicine
This used to be the gold standard before MRI took over and is no longer done routinely. Technetium-99 m can show alterations three to five days after the start of symptoms but is not able to readily distinguish from other causes of increased uptake.
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.
Intramedullary endosteal edema is one of the first signs of bone remodeling. Fredericson developed a classification for stress fractures based on MRI findings
- Grade 1- periosteal edema
- Grade 2- mild bone marrow edema on T2 images only.
- Grade 3 – moderate bone marrow edema on both T1 and T2 images
- Grade 4 – will show a fracture line
Thus, if X-ray is negative, in a routine clinical setting MRI is the investigation of choice.
Differential Diagnoses
- Osteomyelitis
- Tendonitis or tendinopathy
- Exertional compartment syndrome
- Tumors – benign or malignant
- Neuropathic pain
Treatment
Treatment is done by a two-pronged approach
- Healing and consolidation of an existing injury
- Preventing new episodes
Healing and Consolidation of Existing Injury
- Pain relief: Local measures like RICE, analgesics like NSAIDs such as ibuprofen etc
- Rest if needed
- Individuals need to rest from the activity that is responsible for causing the stress
- In some stress fractures 6-8 weeks rest may be necessary
- fracture for six to eight weeks, the time usually a stress fracture takes to heal.
- The activity should be resumed gradually after the rest.
- Immobilization
- Rarely used
- Specific types of fracture however require immobilization- Navicular bone, sesamoids, patella, and posteromedial region of the tibia
- Surgery
- High-risk fractures commonly fail to heal properly and may need surgery in critical cases
- Involvement of lateral cortex of neck of femur
- Anterior cortical bone of the middle third of the tibia
- The base of the fifth metatarsal
- Navicular bone
Fractures of neck femur and pars are special cases and require special mention
Superior side stress fractures of the femoral neck are high risk and should be considered for surgery. Inferior side fractures involving less than 50 percent of the width of the neck should be closely watched while being managed nonoperatively with consideration for surgical intervention if improvement does not occur.
Spondylolysis should be treated with activity modification, core strengthening, and bracing with rest for 2-24 months. Those refractory cases can be considered for surgical management.
Preventing new episodes
The aim is to break the loading cycle by omitting or improving the causative factor. So following measures are taken
- Activity modification for the avoidance of loading
- Correcting sports movements
- Changing sports equipment like footwear
- Changing training locations
- Improving nutritional habits
- Adjusting hormonal imbalance if exists
- Improving muscle conditioning and cardiovascular conditioning
Return to sports may take 4-16 weeks. The gradual return to sports activity should be started after the patient has been free from pain for 10–14 days.
Prognosis
Generally, low-risk stress fractures heal well. Complications are more frequent for low-risk stress fractures. These could be
- Residual pain
- Nonunion
- Inability to return to sports necessitating change
How To Prevent Stress Fracture
Constant control and modification of physical activity, with adequate recovery time, are extremely important.6, 10 It is considered that daily intake of 2000 mg of calcium and 800 IU of vitamin D may be protection factors.6, 9 The kinematics and biomechanical factors predisposing toward such fractures need to be monitored and corrected, through a correct understanding of the sports movements, equipment, orthoses, training surface and all the other factors that may be involved in sports practice.
These tips are typically for fatigue stress fractures.
- Graduated Increment: When you participate in any new sports activity, set small incremental goals. One of the common causes of stress fractures is a sudden increase in unaccustomed activity.
- 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 there is a pain that worsens with the activity, immediately stop the activity and rest for a few days.
- If the pain still persists, seek medical consultation.
References
- Patel D.S., Roth M., Kapil N. Stress fractures: diagnosis, treatment, and prevention. Am Fam Physician. 2011;83(1):39–46. [Link]
- Patel R.D. Stress fractures: diagnosis and management in the primary care settings. Pediatr Clin N Am. 2010;81:9–27. [Link]
- Moreira CA, Bilezikian JP. Stress Fractures: Concepts and Therapeutics. J Clin Endocrinol Metab. 2017 Feb 01;102(2):525-534. [Link]
