2. FATIGUE FRACTURE
Fracture occurs through an otherwise normal bone that is
subjected to repeated episodes of stress, less severe than that
necessary to produce an acute #.
Results from summation of stresses any one of which by itself
would have been harmless.
Overuse injuries.
3. By repetitive submaximal forces that exceed the adaptive
ability of the bone.
Common in athletes & military recruits.
1% incidence in athletes, 20% in runners.
Females prone [female athlete triad]
late adolescence and early adulthood
Increasing incidence in elderly.
4. Weight bearing lower limb bone prone
Tibia – [50%] most common
Tarsals & metatarsals
Specific anatomic sites
- shaft of humerus cricket/ throwing sp.
- ribs golf & rowing
- spine pars # gymnastics
- pubic rami inferior in children, both in
adults
- lower extremities running activities.
5. - Femoral neck any age
- Femoral shaft lower third
- Patella children & young athletes
- Tibial shaft pro 3rd
in children, mid 3rd
in athletes, distal 3rd
in elderly.
- Fibula high shaft – jumpers, distal 3rd
in runners.
- Calcaneum adults / compression stress/ anterior to
tuberosity.
- Metatarsals march # / 2nd
MT neck.
- Great toe sesamoids.
6. PATHOGENESIS
Excessive, repetitive, submaximal loads on bones that cause
an imbalance between bone resorption and formation.
An abrupt increase in the duration, intensity, or frequency of
physical activity without adequate periods of rest may lead to
an escalation in osteoclast activity.
During periods of intense exercise, bone formation lags
behind bone resorption.
7. When bone subjected to hyper physiological loads, its
ultimate strength decreases susceptible to microfractures
Continuous loading microcracks coalesce to stress #.
ETIOLOGY – multifactorial
Depends on type of bone composition, vascular supply,
surrounding muscle attachments, systemic factors, athletic
type.
Role of muscle – M . Fatigue, concentrating forces to
localised area.
8. Intrinsic factors
Hormonal imbalances
- female, estrogen deficiency.
- male athletes – testosterone- inhibits IL-6 – osteoclast
production - activity.
Nutritional deficiencies
Sleep deprivation
Collagen abnormalities
Metabolic bone disorders
9. Stages in development
1. Crack initiation
2. Crack propagation
3. Rapid failure of bone.
Bone can repair itself quickly, pathological strain is
removed before the third stage.
10. Clinical features
History of unaccustomed & repeated activity.
Sequence – pain after exercise, pain during ex, pain without
ex.
Load related pain – early symptom
general health, medications, diet, and menstrual history in
women
Increase in training volume or intensity, a change in
technique or surface, or an alteration of footwear
11. H/O previous stress fractures or other painful sites, and the
presence of eating disorders,
Limb biomechanics - leg length discrepancy, or muscle
imbalance, excessive subtalar pronation.
Focal bone pain with palpation and stressing – Hall mark.
Local swelling- callus –late presentations
Location of pain – medially / femoral shaft
Inaccessible sites – femoral neck - movts
12. Imaging modalitiesConfirm the diagnosis, more information for differential
evaluation.
X- RAY
Normal – 1st
2-3 wks after the onset of symptoms
Periosteal response – 3 months after onset of symptoms.
Periosteal bone formation, horizontal or oblique linear
patterns of sclerosis, endosteal callus, and a frank fracture
line.
13. Gray cortex ovoid lucency with in a thickened area of
cortical hyperostosis radiolucent line with extension
partially or completely across the cortex
cancellous bone a fracture lucency oriented perpendicular
to the trabeculae.
X ray more useful in fibula & metatarsals.
14. Scintigraphy
Sensitive method
Confirming clinically suspected stress fractures.
Acute stress fractures are depicted as discrete, localized,
areas of increased uptake on all three phases of a Tc-99m
Soft-tissue injuries are characterized by increased uptake
only in the first two phases.
Lacks specificity.
15. Indications for bone scan
suspected lesions in the spine or Pelvis
identifying multiple stress fractures,
distinguishing bipartite bones from stress fractures.
- positive images in phase III persists – many months, should
not be used to monitor healing and dictate return to activity.
18. MRI
More specific
Avoids radiation exposure
Less time
More expensive
Grading the stage of certain stress fractures and, therefore,
predicting the time to recovery
femoral neck stress fracture in an athlete.
20. Treatment Overview
Fundamental principle of initial management is REST to
allow the bone remodeling process to equilibrate.
identifying and correcting any predisposing factors.
Hormone replacement therapy.
Training errors - identified and corrected
21. Low risk stress #
Diagnosed on the basis of a thorough history, physical
examination, and radiographs.
A rest period of 1 to 6 weeks of limited weight bearing
progressing to full weight bearing phase of low-impact
activities high impact activities.
22. HIGH RISK STRESS #
predilection for progressing to complete fracture, delayed
union, or nonunion
more aggressive treatment approach
fractures include those in the femoral neck (tension side),
patella, anterior cortex of the tibia, medial malleolus, talus,
tarsal navicular, fifth metatarsal, and great toe sesamoids.
Due to high complication rate treated as acute #
23.
24. HR # of the lower leg and foot - aggressive nonoperative
protocol consisting of non-weight-bearing cast
immobilization.
Exception to this rule is the tension-side femoral neck stress
fracture,which requires internal fixation
26. PREVENTION
Training errors - most frequent culprit and should be
corrected.
Assessment of the type and condition of the running
shoes
Viscoelastic insoles, may help reduce the incidence of
lower-extremity stress fractures.
Education – parents, coaches, military personnel –
periodic rest.
Female athletes – alerted , eating disorders, hormonal
abnormalities.
27. Femoral neck #
High complication rate
Due to hip musculature fatigued due to prolonged activity &
subsequent loss of shock absorbing effect.
Coxa vara & osteopenia
Pain at extremes of rotation.
More common is compression type –benign
28. Distraction or tension stress # - starts in superior cortex
High chance of displacement & progression
Grade 3 or grade 4 tension-side femoral neck stress fractures
should be stabilized with multiple screw fixation to promote
healing and prevent displacement.
avoid lateral entry points below the midportion of the level
of the lesser trochanter
29. Tibial fractures
Most common site [20-75%]
Posteromedial cortex [compression side] most common.
Transverse # common
Longitudinal # ,atypical presentation, MRI
Conservative Rx.
Pneumatic brace – supplemental use – early return of
activities.
30. More problematic – anterior cortex of middle 3rd
of shaft.
X ray – subtle, high incidence of suspicion
Both constant tension from posterior muscle forces and
hypovascularity of the anterior aspect of the tibia predispose
this site to nonunion or delayed union.
Tension side # occurs in those performing repetitive
jumping & leaping activities.
31. V –shaped defect in the anterior cortex
Callus formation – absent
Dreaded black line.
Anterior tibial stress fractures with an established transverse
cortical lucency have limited healing potential even with
activity modification
Reamed intramedullary nailing predictably leads to healing of
the stress fracture in a shorter time course.
32.
33. Medial Malleolus
Repetitive impingement of the talus on the medial malleolus
during ankle dorsiflexion and tibial rotation.
The fracture line is vertical or oblique and originates from
the junction of the tibial plafond and the medial malleolus.
Athletes desiring early return to competition, with a
complete fracture line – surgery.
34. Navicular #
sprinting and jumping sports.
Insidious onset vague medial arch pain
In the sagittal plane in the relatively avascular central
third of the bone.
Anatomic AP view with foot inverted
CT, MRI.
Acute # - an initial 6-week period of non weight-
bearing cast immobilization.
Delayed diagnosis or delayed union, compression screw
stabilization
Displaced fractures and established sclerotic nonunions
require ORIF and supplemental bone graft.
35.
36. Fifth metatarsal
proximal diaphysis of the bone just distal to the
tuberosity and the ligamentous structures.
basketball players.
problematic site is in the proximal 1.5 cm of the
diaphysis, where cortical hypertrophy commonly occurs
in running and jumping athletes, rendering the zone
relatively avascular with a narrow medullary canal
propensity for delayed union or nonunion and have a
high risk of refracture after nonoperative treatment.
37. Acute # non wt bearing cast immobilisation.
Intermediate delayed union intramedullary compression
screw placement after the medullary canal at the fracture site
has been adequately drilled to remove fibrous tissue and
sclerotic bone
Estabilised NonU – grafting.
functional metatarsal brace should be used for atleast 1
month after surgery – reinjury.
38. Great toe sesamoids
predominance at the medial sesamoid
Repeated dorsiflexion of the great toe during running and
jumping
weight-bearing anteroposterior and lateral views as well as
an axial view centered on the sesamoids.
Acute stress # Rx with 6 weeks of non-weightbearing cast
that extends to the distal tip of the toe to prevent
dorsiflexion
Sesamoidectomy.