Foot stress fractures Flashcards
Stresses on foot of running
- heel weight bearing = 110%
- Running = 250%
- forefoot running = 300%
RF for foot stress fractures
- Female athletes
- Extrinsic factors (inc env)
- Intrinsic factors
Female quintuple
- low BMD
- low BMI
- oligo/a-menorrhoea
- inc age
- poor nutrition
How does menstrual irregularity increase stress fracture risk?
- delayed menarche 4x risk
- amenorrhoea = 2x
How does poor nutrition increase stress fracture risk?
- elevated dietary restraint
- no calcium supplementation 2x
- previous ED diagnosis 5x
How does BMI affect risk of stress fracture
2-3x inc in underweight
less soft tissue to re-distribute force
Risk of stress fracture in female + BMI<19 + late menarche + previous fracture
35% yearly risk
Risk of stress fracture in female triad + >12h a week training
46% annual
Which athletes with stress fractures require a BMD assessment?
- Female quintuple
- > 50yrs
otherwise, DEXA not required
Extrinsic factors inc risk of SF
- training regime
- type- running, ballet
- training surface
- footwear
Intrinsic risk factors for stress fracture
- bony anatomy
- stiff joints
- leg length discrepency
muscle + BMI - fitness and experience
- FHx
- smoking
How are stress fractures classified?
- Fatigue (normal bone, abnormal stress)
- Insufficiency (abnormal bone, normal stress)
- Pathological
classification of BSIs
Fredericson
Grading of stress fractures and implications for Mx
Grade 4+5 will need surgical intervention + early referral
Hx stress fracture
- localised crescendo pain
- progressive pain
- eventually day-to-day activities/night
- female quintuple
- ask about training
Stress fracture O/E
- localised tenderness
- swelling with delayed presentations
imaging for stress fractures
- plain radiograph- often normal till 2-3 months
- CT
- MRI - gold standard
Low risk bones of non-union
- Distal 2-5 metatarsal
- Cuboid
- Cuneiform
- Calcaneum
Good blood supply
High risk bones of non-union
- Proximal second metatarsal (forces through midfoot)
- 5th metatarsal dia/meta-physeal junction (watershed area for blood supply)
- Navicular
- Talus
- Sesamoid
- Ant process of calcaneum
Need early aggressive Tx
Fracture features on radiograph indicating increased risk of non-union
- sclerotic or cystic appearance
- MRI appearance of complete fracture on T1/2
- Displaced fracture
How are foot fractures managed based on non-union risk?
Risk stratification is done by age (>50) + presence of female quintuple
- Low risk non-union = activity modification (prolonged if high risk)
- High risk non-union = immobilise/surgical stabilsation
Grade 4-5 grade fracture Mx
surgical
non-surgical Mx principles
- Analgesia
- Mobilisation based on underlying symptoms- crutches, boot- make sure ADL are pain free. if not pain free, won’t heal as microfractures
- Correcting underlying bone health/deficiencies
- Maintaining VO2 max- treadmills, antigravity treadmill, swimming
Rules for RTP stress fracture
FWB for 2 weeks
Follow 30:10 rule
- 1/3rd normal pace
- 1/3rd typical distance
- Increasing in 10% weekly increments