Tibial Stress Fracture - Risk Factors

The risk of developing a tibial stress fracture is influenced by a multitude of factors. Both intrinsic and extrinsic factors affect the amount of compressive-, shear- and bending stresses acting on the tibia, and the amount of stress that is tolerated.

Last revised: 18.02.2020.

Ken Fredin

Physical therapist, Oslo, Norway

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A lot of research has been conducted on intrinsic and extrinsic risk factors related to the development of tibial stress fractures (tibial SFs). Of those, the most important risk factors are female sex and previous stress fracture.

 

Stress fractures in women

 

Women are at twice the risk of developing a tibial stress fracture in a wide range of sports (1-3). While the etiology of this is multifactorial, it has partially been attributed to The Female Athlete Triad (1). Other factors include bone geometry, biomechanical differences, late menarche, and prior participation in selected "leanness sports", including dance and gymnastics (3,4).

 

A study by Tenforde and colleagues on high school track and field athletes and cross-country runners found that the risk of stress fracture in women were closely related to the following independent factors (4):

 

  1. Previous history of stress fracture (6.5 times increased risk)

  2. BMI under 19 (2.8 times increased risk)

  3. Late menarche (age > 15 years) (3.9 times increased risk)

  4. Previous participation in "selected leanness sports" (4.2 times increased risk)

 

In their prediction model, they fund that the prospective risk of a stress fracture increased in females with two or more risk factors (4):

 

Risk factors       Prospective risk of SF

0-1                           1.6 %

2                             12.8 %

3                             35.7 %

4                             100 %

 

Female Athlete Triad

The Female Athlete Triad refers to the interrelationship between low energy availability (with or without disordered eating), menstrual dysfunction (amenorrhea, missing menstrual periods), and low bone mineral density (osteopenia/osteoporosis) in physically active females.

 

Relative energy deficiency in sports (RED-S) reduces female estrogen levels, which is detrimental to bone health (5), and it considered as one of the main reasons why women are at an increased risk of developing bone stress injuries, including stress fractures and medial tibial stress syndrome (shin splints).

 

Eating disorders

 

The prevalence of eating disorders is significantly higher in female athletes than non-athletes (6). In one study of 1000 athletes and non-athletes, 18 % of female athletes were diagnosed with an eating disorder, compared to 5 % in the control group (7). In a similar study of 3316 female athletes, the same percentages were 20 and 9 % (7).

 

Female athletes with a previously diagnosed eating disorder had five times greater risk of developing a stress fracture compared to those without a previously diagnosed eating disorder (8). In another study, female athletes with a history of stress fractures more frequently reported an eating disorder than non-injured athletes (9).

 

History of previous stress fracture

 

A history of previous stress fracture is the most robust risk factors for both genders (8,10,11). In a prospective study, men and women with a prior stress fracture had 7.0 and 6.5 times increased risk of a prospective stress fracture (8). Another study reported 6.5 times greater risk among female athletes (10).

 

Bone geometry

 

Bone geometry and bone mineral density (BMD) affect tibia's ability to tolerate stress (9,12,13). Several studies have shown that athletes with a history of previous tibial stress fracture have less tibial BMD, thinner cortices, and narrower tibia's than athletes without a previous stress fracture (13-19).

 

While compressive strength is proportional to CSA, bending and torsional strength are exponential to what is known as the cross-sectional moment of inertia (CSMI), which is related to the cortical cross-sectional area and its distance from the axis (12).

  

This means that a 20 % increase in CSMI increases mechanical resistance to bending and torsional loads by 80 %, and only modestly increasing mechanical resistance to compressive loads. Therefore, individuals with narrower tibiae and/or reduced tibial CSA have less mechanical resistance to loads, which increase stress and makes them prone to bone stress injuries, including stress fractures and MTSS.

 

Other risk factors

 

There is a great number of risk factors associated with tibial stress fractures. Some of these are presented below, with references to relevant research.

 

  • Female gender (1-3)

  • Loss of menstrual periods (amenorrhea) (4)

  • Late menarche (4)

  • Bone geometry and bone mineral density (13-19)

  • Previous participation in "leanness sports" (4)

  • Eating disorders (4,8,9)

  • Low BMI (4)

  • Nutritional deficiencies (20)

  • Reduced testosterone levels in men (20)

  • Caucasians have increased risk of developing stress fractures African-Americans (21)

  • Previous history of stress fracture (4,8,10,11)

  • Sedentary lifestyle/low baseline fitness (9,15)

  • Training volume/running distance (3,5)

  • Running surface/footwear (3)

  • Reduced foot pronation (3,9)

  • High peak hip adduction (3,13,22-24)

  • Increased vertical loading rates of the tibia (3)

  • Pes cavus foot alignment (3)

  • Leg-length discrepancy (9)

  • Genu valgum (9)

  • Wider pelves (within gender) (21)

  • Lower thigh muscle CSA (9,15)

  • Knee replacement (25)

  • Smoking (26-29)

The content on this page is for educational purposes only, and should not replace advice given to you by a healthcare provider. MTSS.co does not provide medical advice.
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