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S
tress
fractures
in
the
foot
and
ankle
of
athletes
R
ev
A
ssoc
M
ed
B
ras
2014; 60(6):512-517
513
W
hen
should we
suspect
a
stress
fracture
in
the
foot
?
Suspected injury is based on the details from the medi-
cal history, general physical examination and orthopedic
physical examination. It is important to establish the re-
lationship between the start of painful symptoms and
physical activity, generally performed repetitively, abrupt
changes in the amount of training and the presence of
risk factors (
D
).
8,11,12
Initially, pain emerges at the end of the exercises and
intensifies over some weeks; it may occur during the enti-
re activity, and be constant during walking. Pain worsens
and transforms training into suffering. Training becomes
increasingly painful and difficult to continue. Even after
some days of rest, returning to activities too early leads
to recurrence of the pain (
D
).
4-6,8
Recommendation
Stress fractures in the feet of athletes should be suspec-
ted in the presence of insidious pain associated with in-
creased exercise intensity.
W
hich
complementary
exams
should
be
requested
for
the
diagnosis
?
After the medical history and clinical exam, plain radiogra-
phy, bone scintigraphy, computerized tomography and
magnetic resonance imaging have been used to aid the
diagnosis (
D
).
8,11
Despite its low sensitivity, simple radio-
graphy is recommended to start the investigation (
D
).
12
In
more advanced cases, cortical or medullary fracture lines,
regional osteopenia, sclerosis and callus formation may be
noted. Unfortunately, radiographs are initially negative in
70% of stress fractures and might not show evidence of in-
jury for 2 to 4 weeks after the start of symptoms (
C
)
13
(
B
).
14
Rupture of the bone cortex can be demonstrated th-
rough computerized tomography and evidence of perios-
titis can also be detected in this manner. The sensitivity
of computerized tomography is higher than radiography;
however, compared with bone scintigraphy and magnetic
resonance injury, the sensitivity for revealing stress frac-
tures is low, resulting in a higher rate of false negatives
(
C
).
16
Owing to the high rate of false negatives using ra-
diographs at the start of the course of stress fractures, ad-
ditional diagnostic imaging is often necessary. Bone scin-
tigraphy has traditionally been the test of choice in this
situation, but has been supplanted by magnetic resonan-
ce imaging (
B
).
17,18
Despite its sensitivity, bone scintigra-
phy is not specific and may produce false positive results
in 13 to 24% of cases (
C
).
13
Magnetic resonance imaging has numerous practical
advantages over scintigraphy. It provides precise anato-
mical resolution, can differentiate a stress reaction from
a stress fracture, as well as being a noninvasive, multipla-
nar exam that does not require radiation. It is more sensi-
tive and specific, provides greater information and is ca-
pable of detecting pre-radiographic bone changes. The
disadvantages include the higher cost, contraindications
relating to claustrophobic patients and those with metal
implants or surgical materials (
C
).
13
Follow-up using computerized tomography or magne-
tic resonance imaging may also be useful to monitor hea-
ling of the stress fractures and determining if there is a de-
lay in healing that could require surgical intervention(
D
).
6
Recommendation
In cases of suspected stress fractures, plain radiography
of the site of pain should be requested, with diagnosis in
the majority of cases via more sensitive and specific ima-
ging exams (magnetic resonance imaging).
W
hat
are
the
factors
that
favor
stress
fractures
?
Various factors contribute to the pathogenesis of the di-
sease, which may be classified into 2 sub-types: intrinsic
and extrinsic. In general, extrinsic factors are related to the
type and rhythm of training, the use of unsuitable foot-
wear and sports equipment, precarious physical conditio-
ning, the training location, environmental temperature
and insufficient recovery time of previous injuries. Intrin-
sic factors include age, sex, race, bone density and structu-
re, hormonal, menstrual, metabolic and nutritional balan-
ce, sleep pattern and collagen diseases (
D
)
4,5,8
(
C
).
19,20
Prospective and retrospective studies show a higher
incidence among Caucasians. When compared to Ameri-
can black and Hispanic individuals, white individuals are
more susceptible to stress fractures (
D
).
22
The same occurs
with age: older individuals present a higher incidence of
such fractures (
B
).
7
Stress fractures are less common in
children than adolescents and adults (
D
).
23
In relation to
sex, some studies have shown that military women have
an incidence 5 to 10 times higher than men (
B
).
7
With regard to genetic factors, studies on identical
twin military recruits submitted to the same treatment
in quantity, duration and intensity reveal fatigue fractu-
res in the metatarsal bones in both (
B
).
7
In relation to biomechanical factors, a high longitu-
dinal arch of the foot, difference in the length of the lo-
wer limbs and a marked varus foot associated with mul-
tiple stress fractures have been observed (
B
)
15,21
(
C
).
19,20,24