Stress Fracture



  • Stress fractures are overuse injuries caused by cumulative microdamage from repetitive bone loading.
  • Stress fractures occur in different situations:
    • Fatigue fracture: abnormal repetitive stress applied to normal bone (e.g., young college athletes or new military recruits with increased physical activity demands and inadequate conditioning); common sites include tibia, fibula, metatarsals, femoral neck, and navicular.
    • Insufficiency fracture: normal stress applied to structurally abnormal bone (e.g., femoral neck fracture in osteopenic bone, metabolic bone disease); common sites include spine, sacrum, femoral neck, and medial femoral condyle.
    • Combination fracture: abnormal stress applied to abnormal bone (e.g., female long-distance runners with premature osteoporosis from athletic triad)
  • Weight-bearing bones of the lower extremity are most commonly affected at the following sites:
    • Tibia/fibula (most common)
    • Metatarsals (second most)
    • Navicular
    • Femoral neck
    • Pars interarticularis
  • High-risk stress fractures occur in zones of tension or areas with poor blood supply and are more likely to result in fracture displacement and/or nonunion. High-risk sites include the following:
    • Femoral neck
    • Anterior tibial diaphysis
    • Sesamoids
    • Pars interarticularis of lumbar spine (L4, L5)
    • 5th metatarsal at metaphyseal–diaphyseal junction
    • Proximal 2nd metatarsal
    • Medial malleolus
    • Tarsal navicular
    • Patella
    • Talar neck
  • Synonym(s): march fracture; fatigue fracture



  • Greatest incidence in 15- to 27-year-olds
  • Females > males
  • Accounts for up to 20% of visits to sports medicine and orthopedic clinics


  • Lifetime athletic stress fracture is 10% (1).
  • Affects up to 6.9% of male and 21.0% of female military members

Etiology and Pathophysiology

  • Bone is dynamic and constantly remodeling in response to applied physiologic stress.
  • Repetitive loading or overuse causes microfractures that fail to heal due to imbalance between bone resorption and bone formation.
  • If microdamage accumulates in excess of reparation, bony fatigue leads to stress fracture.

Risk Factors

  • Intrinsic
    • Females are at 2.3 times higher risk than males.
    • Female athlete triad
    • Small tibial width
    • Later menarche, amenorrhea, or irregular menses
    • History of stress fracture
    • History of osteoporosis, osteomalacia, rheumatoid arthritis, prolonged corticosteroid therapy
    • BMI <19 kg/m2
    • Skeletal malalignment: pes cavus/planus, leg length discrepancies, excessive forefoot varus, tarsal coalitions, prominent posterior calcaneal process, tight heel cords
    • Biomechanical factors such as increased vertical loading rate (e.g., heel-to-toe running instead of forefoot striking)
  • Extrinsic
    • High-risk exercises—track and field, cross country
    • Training regimen—running >20 miles/week or training >5 hr/day
    • Nutritional—inadequate caloric intake or history of eating disorder
    • Chronic low vitamin D
    • Rapid increase in mileage, running pace, or training volume
    • Inappropriate footwear
    • Hard training/running surface
    • Inadequate recovery or rest and training with fatigued muscle
    • Lifestyle: high alcohol intake or smoking
    • Meds: glucocorticoids, anticonvulsants, antidepressants, depot-medroxyprogesterone acetate (DMPA), methotrexate, antiretrovirals, chronic cannabis use, >5 years of bisphosphonate use

General Prevention

  • Prevention is the key especially in adolescent athletes (1).
  • Graduated increments in training load intensity: no >10% per week
  • Optimize energy balance.
  • Diversify sports participation (minimizing sports specialization).
  • Reduce intensity and duration of activity if new-onset pain.
  • Proper footwear (Athletes should have a gait analysis prior to training.)
  • Increasing dynamic physical activity (jumping; plyometric training) increases bone density and resistance to mechanical stress.
  • Decrease vertical loading rate either by switching to forefoot strike running or (if continuing with heel-to-toe strike) by using a heel pad insert.
  • Vitamin D supplementation (800 IU/day) in combination with calcium (2,000 mg/day)

Commonly Associated Conditions

  • Osteoporosis/osteopenia
  • Female athlete triad
  • Metabolic bone disorders

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