Transcript Stress Fracture

Stress Fractures
Normal Anatomy
• Bone remodels under wolff’s law
• Remodelling takes place via
mechanotransduction
• Remodelling is based on the force and load
placed through the bone
• If loading on a bone increases the bone will
remodel itself to become stronger and resist
the loading
• If loading on a bone decreases the bone will
become less dense and weaker due to the
lack of stimulus
• Remodelling occurs quickly in cancellous bone
• Remodelling occurs slowly in cortical bone
Pathology
• Partial or complete fractures
resulting from repetitive and
excessive mechanical stress on
normal bone
Pathology
• Normal Stress
• Load and stress applied to bone with
adequate time to remodel
• Bone remodels according to Wolff’s Law
• Stress Reaction
• Under repetitive loads without sufficient
time to remodel bone will fatigue and fail
• Osteoclastic activity is greater than
osteoblastic activity
• Results in microfractures
• Stress Fracture
• Continued stress results in cortical break
Mechanism of Injury
• Insidious
• Repeated stress or load e.g
running
Risk Factors
• Intrinsic
• Female
• Low bone mineral density
• Nutritional deficiencies
• Hormonal irregularities
• Leg Length discrepancies
• Genu Valgum
• Poor lower limb muscle mass
• Extrinsic
• Running or jumping sports
• Rapidly increasing training
program
• Poor training surface
• Running downhill
• Poor training footwear
• Smoking
Classification
• Location and type of the fracture
predictive of healing
• Compression stress fractures
more likely to heal with
conservative measures
• Tension stress fracture usually
require surgical intervention
• Tension forces can displace
fracture site creating instability
High Risk Fractures
Femoral Neck Stress Fracture
• High morbidity in runners
• Significant complications if missed
• Fracture completion
• Avascular necrosis
• Arthritis changes
• Anterior hip or groin pain worse with activity
• Extremes of passive ranges of movement
maybe painful
• Superior aspect of the femoral neck
• Tensile forces
• Surgically managed
• Inferior aspect of the femoral neck
• Compressive forces
• Can be managed surgically or conservatively
depending on fatigue line
Anterior Tibial Shaft Stress Fracture
• Tension type stress fracture
• Poorly localised anterior leg pain
• Risk of non-union
• “dreaded black line” anterior
tibia radiograph at middle-distal
third junction of anterior tibia
• Initially conservative but surgical
management required 60% of
the time
Navicular Stress Fracture
• Common in athletes requiring a
“push off” e.g sprinters, middle
distance runners
• Navicular avascular
• Compression between talus and
cuneiform
• Vague, poorly localized foot pain of
medial dorsum of the foot
• Tenderness “N-spot” on the dorsal
navicular
• Can be managed conservatively if
no cortical disruption present,
otherwise surgically managed
Talar Neck Stress Fracture
• Rare
• Usually report a trauma
th
5
Metatarsal Stress Fracture
• Less common metatarsal fracture
• Usually in the diaphysis on the lateral
side and progresses medially
• Tension type
• Pain with weight bearing
• History of trauma or change in
routine/environment/footwear
• Tenderness palpation
• Surgery considered for
• Failed conservative management
• Displaced fracture
• Elite athlete with need for early return
Low Risk Fractures
Femoral Shaft Stress Fracture
• Usually proximal third
• Insidious onset
• Non-specific pain localised to
the groin, thigh or knee
• Conservatively managed
Pelvic/ Pubic Ramus Stress Fracture
• Groin pain
• Pain with single leg stance
• Most commonly inferior pubic
ramus
• Conservatively managed
Fibula Stress Fracture
• Diffuse lateral leg pain
• Usually affect the distal third
• Conservatively managed
Calcaneus Stress Fracture
• Heel pain
• Worse on running and jumping
• Posterosuperior tenderness on
palpation
• Conservatively managed
nd
2
th
-4
Metatarsal Stress Fracture
• Most commonly 2nd and 3rd
metatarsal
• Forefoot pain on activity
• Tenderness on palpation
Posteromedial Tibial Stress Fracture
• Shin pain with weight bearing
• Focal tenderness over
posteromedial tibia
• Occur posteromedial in the
proximal or distal parts
• Conservatively managed
Subjective Examination
• Localized area of pain
• Insidious onset
• Occurs with activity that
gradually gets worse
• Advanced stages pain could be
at rest
• History of repeated activity
Objective Examination
• Focal tenderness
• Pain with percussion
Further Investigation
• MRI
• Bone scan
• CT
Management
• Management plan determined by location and risk of fracture
• Guided by surgeon
Conservative
• Activity modification to a pain free threshold
• “if it hurts to do it, then don’t do it”
• Reduce risk factors
• NSAID’s should be avoided
• Gradually progress weight bearing activity as pain allows
• Maintain general body conditioning, fitness and strength with pain
free exercise
• Roughly 4 – 8 weeks for adequate healing
Plan B
• Surgical interventions depend on
site
References
• Aweid, B., O. Aweid, S. Talibi and K. Porter (2013). "Stress fractures."
Trauma 15(4): 308-321.
• Gallo, R. A., M. Plakke and M. L. Silvis (2012). "Common leg injuries of
long-distance runners: anatomical and biomechanical approach."
Sports Health 4(6): 485-495.
• Kahanov, L., L. E. Eberman, K. E. Games and M. Wasik (2015).
"Diagnosis, treatment, and rehabilitation of stress fractures in the
lower extremity in runners." Open Access J Sports Med 6: 87-95.
• McCormick, F., B. U. Nwachukwu and M. T. Provencher (2012). "Stress
fractures in runners." Clin Sports Med 31(2): 291-306.