What are Stress Fracture and Why do we get them?
Thursday, August 18, 2011 at 8:20AM What are Stress Fractures?
Stress fractures were first described in sports medicine in 1958. Since then the prevalence of stress fractures has been increasing, especially in athletes and military recruits. The prevalence has been reported to be between 0.4%-49% in athletes and military recruits with 10%-31% occurring in running sports. A stress fracture is the result of an accumulation of micro-damage from repetitive loading of a bone leading to fatigue within the bone causing a crack. The crack does not traverse the entire bone compared to a frank fracture from trauma, which separates the two ends of the bone. A stress fracture is considered an overuse injury and can arise in any bone; however 95% occur in the lower limb with the tibia being the most common bone.
What causes a Stress Fracture?
The direct cause is not fully understood. It is suggested that stress fractures represent a failure of functional adaptation.
What are the Risk Factors?
- Intrinsic factors: age, gender, race, poor fitness level, and decreased muscular strength.
- Extrinsic factors: intense training regimen, improper footwear, hard training surfaces, and type of sport.
- Biomechanical factors: low bone mineral density and bone geometry.
- Anatomic factors: foot shape, leg length discrepancy, and knee alignment.
- Hormonal: delayed menarche, menstrual disturbances, menopause and contraception.
- Nutritional: low calcium and vitamin D, eating disorders and female athlete triad.
Training regimen seems to be the most influential risk factor. For example, improper increase in running mileage, abrupt or rapid changes in duration, frequency or intensity of training all lead to an increased risk of stress fractures. This mainly occurs due a lack of adequate rest to allow the bone to respond to the new stimulus and strengthen itself via remodeling.
What are the Symptoms?
People with stress fractures describe a sudden onset of pain over the affected region without having experienced any form of trauma. Initially the pain will occur during the provoking activity and it is relieved by rest. With continual activity at the same level, the pain will be felt after the activity and will later cause the athlete to cease the sport. Eventually the patient will experience pain at rest. Imaging studies, such as x-rays, bone scan, CTscan or MRI may be necessary to diagnosis a stress fracture.
What is the treatment and can stress fractures be prevented?
If a stress fracture is diagnosed the patient must eliminate the provoking activity and rest. In some cases, immobilization (cast, protective orthotic braces), bed rest or crutches are prescribed. Some stress fractures may require surgery, depending on the location and severity. An alternative training program may be implemented to maintain fitness, such as water running or swimming during the period of rest. Alternative training programs should be confirmed with the patient’s medical practitioner.
Once the patient achieves 2-3weeks of pain free full weight bearing activity they may gradually resume their sport. As a rule of thumb, activity should not be increased more than 10% per week. If there is recurrence of pain the patient must be placed on a 2 week program of modified activity, until the pain is resolved.
There are many suggestions to help prevent stress fractures. It is important to maintain muscular strength, allow adequate rest between intervals, eat a healthy balanced diet, and implement gradual changes to training regimen (intensity, type, or materials used). At Absolute Endurance we encourage proper coaching, strength training, nutrition and manual therapy to help prevent stress fractures from occurring. Keep your body strong so you can perform at your best levels.
Dr. Jaclyn Kissel BSc, CSCS, DC, FRCCSS©
References
- Shima Y, Engerbresten L, Iwasa J et al. Use of Bisphosphonates for the Treatment of Stress Fractures in Athletes. Knee Surg Sports Traumatol Arthrsc. 2009; 17: 542-550.
- Berger F, de Jonge M, Maas M. Stress Fractures in the lower extremity. The Importance of Increasing Awareness amongst Radiologists. European Journal of Radiology. 2007; 67:16-26
- Edwards WB, Taylor D, Rudolphi TJ et al. Effects of Running Speed on Probabilistic Stress Fracture Model. Clinical Biomechanics. 2010; 25: 372-377
Reader Comments (1)
Stress fractures should be a motivation for people to pursue healthy habits. That way, you lessen the chances of you getting these.
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