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Three Part Question

In [patients with below knee bony pain] are [current levels of activity or previous levels of
activity] a [greater risk factor for lower limb stress fractures]

Clinical Scenario

A 24 year old female presents to the emergency department with atraumatic bony pain in her left foot. She tells you that she is a keen runner and is in the process of training for a marathon. You wonder if her previous activity levels or current increase in activity are a greater risk factor for a stress fracture.

Search Strategy

Ovid MEDLINE(R) 1946 to July Week 1 2015

(exp Tibia/ OR exp Fibula/ OR lower limb.mp. OR exp Lower extremity/ OR exp Foot/ OR exp Foot Bones/) AND (exp Fractures, Stress/ OR exp Athletics Injuries/ OR fatigue fracture.mp. OR stress syndrome.mp. ) AND (exp Exercise/ OR exp Physical Fitness/ OR physical activity.mp.) AND (exp Risk Factors/) Limit (English language AND humans AND all adults (19 plus))

Search Outcome

24 Hits and 11 Relevancies

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Hespanhol 2013 Brazil	200 Recreational runners	Prospective cohort study to determine two factors, What is the incidence of running related injuries and what factors contribute towards this.	Level of activity relevant risk factor	Minimal impact 1.01 probability	Low follow up levels Only 12 weeks of review Simple methodology.
			High impact training	1.46 probability of stress fracture
Mohen 2012 Netherlands	35 Dutch Male military recruits	Case-control study to assess risk factors for MTSS and prognostic factors	Risk factor for stress fracture	BMI significant risk	Poor description of methodology Small population group Assessed MTSS not stress fractures Aimed to assess risk factors but very specific measurements/only measured physical internal risk factors not external risk factors. No intervention
Newsham-west 2009 New Zealand	199 masters level football players ages 40-49 years	Descriptive cross-sectional study in order to profile training habits and related injuries in football players	Activity acted as a risk factor	1-4 hours of training per week risk factor	Not related to running Didn’t define what the injuries were Didn’t have a follow up Poor methodology
			Number of lower limb stress fractures	64 injuries/100 players 67.3% occurred during games
Hubbard 2009 USA	146 healthy collegiate athletes	Descriptive cross-sectional study to assess risk factors for MTSS	Activity levels relevant risk factor	Control = 8.8 years/ 26.5 miles per week MTSS = 5.3 years/ 27.1 miles per week	Focused on intrinsic factors not extrinsic factors in methodology yet mentioned in results No focus on athletics activity Poor follow up
Van middelkoop 2008 Netherlands	1500 recreational runners 694 responded to questionnaire	Questionnaire based descriptive cross-sectional study to identify risk factors for lower extremity injuries in runners	Activity levels relevant risk factor	Running less than 40km per week was protective >60 km per week = 21.3% Number of races participated in 0-3 = 0.39 p-value/ >11 = 0.08 p-value	Large study design may limit specifics of study
Van Gent 2009 Netherlands	Review article	To present an overview of published reports describing the incidence of various running injuries of the lower extremities	Activity levels relevant risk factor	Training frequency was a significant risk factor of overall injury RR=3.68 Increase of training of 1d/w also had OR = 1.19 Distance had an increased risk of lower limb injuries between OR= 1.6- 7.4	No clear focus aims of study Looked at overall injuries not specific injuries and did not clarify these
Zifchock 2006 USA	49 Runners 25 control and 24 who had injuries	Controlled Trial with 3 aims 1. To compare kinetic symmetry in healthy runners 2. compare kinetic SI values between runners who have 1 injury 3. Compare affected to unaffected leg kinetic values	Activity levels relevant risk factor	104 monthly miles in control group 115 monthly miles in group with Tibial Stress Fracture Speed relevant 3.7m/s in control group 3.8m/s in TSF group	Running not relevant to subject aims
Shaffer 2006 USA	2962 female Marine Corps recruits	Cohort Study to identify risk factors for stress fractures at boot camps.	Activity levels relevant risk factor	Low aerobic fitness and no menses in past year significantly increased risk factors Slowest time AOR = 3.54%	Didn’t explain times of aerobic fitness Not accurate measurements
Hreljac 2000 USA	40 runners- 16 female and 24 male divided into 2 groups	Cohort study to identify biomechanical and anthropometric variables that contribute to overuse injuries in runners	Risk factor for stress fracture	Biomechanical factors more significant than external factors	Small population size Not much follow up
			Activity levels relevant risk factor	No
Hoffman 1999 Israel	136 male military recruits	Cohort study to examine the effects of pre-induction strength and fitness levels on the incidence of lower extremity overuse injuries	Activity levels relevant risk factor	58.8% participated in no physical conditioning prior to training in this group 11% received stress fractures Compared with the physical active group only 7% suffered stress fractures Those who had competitive sports background suffered no fractures	Unable to access tables of data Good study design Poor follow up Relatively small sample size No clear definition of aerobic fitness
Cline 1998 USA	127 female soldiers: 78 control/ 49 confirmed stress fracture	Case control study to identify characteristic and factors associated with increased risk for stress fractures in military women	Activity levels relevant risk factor	Leisure activity energy expenditure (kcal/day) tended toward association with lower stress fracture risk as expenditure level increased (p=0.06)	Full text not available Self-reporting may not be accurate

Comment(s)

10 Studies discussed the link between exercise and an increased risk of lower limb stress fractures Of these 10 2 stated that exercise activity was of no or little statistical significance 4 suggested that increased exercise was protective 4 suggested that consistent low levels of exercise were protective All suggested that acute short term increases in exercise were likely to increase risk All suggested that previous injury to the lower limb was a significant risk factor 2 studies suggested that BMI was the current most dangerous risk factor.

Clinical Bottom Line

Acute episodes of increased activity, such as training for upcoming races or major competitions produce the most significant risk factor for potential lower limb stress fractures.

References

1. Hespanhol Junior LC Previous injuries and some training characteristics predict running-related injuries in recreational runners: a prospective cohort study. Journal of Physiotherapy 2013 Dec; 263-9,
2. Moen MH Risk factors and prognostic indicators for medial tibial stress syndrome. Scandinavian Journal of Medicine & Science in Sports 2012 Feb; 34-9:
3. Newsham-West R Training habits and injuries of masters' level football players: a preliminary report. Physical Therapy in Sport 2009 May; 63-6:
4. Hubbard TJ Contributing factors to medial tibial stress syndrome: a prospective investigation. Medicine & Science in Sports & Exercise. 2009 Mar; 490-6:
5. Marienke Van Middelkoop Risk factors for lower extremity injuries among male marathon runners Scandinavian Journal of Medicine & Science in Sports 2008 Dec; 691-7:
6. Bobbie RN van Gent Incidence and determinants of lower extremity running injuries in long distance runners: a systematic review British journal of sports medicine 2007 Aug; 469-80:
7. Rebecca Avrin Zifchock Kinetic asymmetry in female runners with and without retrospective tibial stress fractures Journal of biomechanics 2006; 2792-7:
8. Richard A. Shaffer Predictors of Stress Fracture Susceptibility in Young Female Recruits American Journal of Sports Medicine 2006 Jan; 108-15:
9. ALAN Hreljac Evaluation of lower extremity overuse injury potential in runners Medicine and science in sports and exercise 2000 Sep; 1635-41:
10. Jay R Hoffman The effect of leg strength on the incidence of lower extremity overuse injuries during military training Military medicine 1999 Feb; 153-6:
11. Alana D Cline Stress fractures in female army recruits: implications of bone density, calcium intake, and exercise Journal of the American College of Nutrition 1998 Apr; 128-35,