Insufficiency. Fracture ofthe. Talus: Diagnosis with. MR Imaging'. Hilary. Umans,. MD. Helene. Pavlov,. MD. 439. PURPOSE: To describe the clinical setting.
Hilary
Umans,
MD
Helene
Insufficiency Diagnosis
Pavlov,
Fracture ofthe with MR Imaging’
PURPOSE: To describe the clinical setting and pattern of talar insufficiency stress fractures as diagnosed with magnetic resonance (MR) imaging. MATERIALS AND METHODS: The authors retrospectively reviewed the clinical history and MR images from four patients with five talar insufficiency fractures. All patients were women (age range, 30-70 years). Images were evaluated for the location and orientation of fractures and the presence of concomitant osseous and soft-tissue injury. Concomitant fractures were identified in two patients. Only two fractures were typical in location and orientation at the talar neck. Three fractures were atypical in location and orientation. One occurred horizontally in the talar body and two occurred in the posteromedial talus (one was oriented vertically and one horizontally). Two patients had associated concomitant stress fracturesone in the distal tibia and one in the calcaneus. RESULTS:
CONCLUSION:
MD
The
location
and
R
of the orthopedic and radiology literature revealed 11 of talar stress fracture. The talar fracture is classically described
EVIEW
cases stress as
a fatigue
either basic in
stress
increased training.
the
fracture
literature
were
MATERIALS We
retrospectively
history
and
diagnosis and be determined
five talar
and
imaging.
evaluated between
4641.415
Ankle,
#{149}
MR. 4641.1214 #{149}Fractures, insufficiency, 4641.419 #{149} Fractures, MR. 4641.121411, 4641.121413, 4641.121415 . Osteoporosis, 4641.56
Radiology
I
From
1995;
the
197:439-442
Department
of Radiology,
Albert
Einstein College of Medicine and Montefiore Medical Center, 111 E 210th St, Bronx, NY, 10467 (H.U.); and the Department of Radiology, Hospitat for Special Surgery, New York, NY (H.P.). Received April 28, 1995; revision requested May 26; revision received June 15; accepted June 20.
Address RSNA,
reprint 1995
requests
to H.U.
typi-
and
patients. performed performed following spin-echo
fractures.
were gender,
clinical with
Patients teaching hosThe clinical
evaluated to and nature
of symptoms.
nuclear MR
medicine
images
were
bone
obtained
in all
Computed tomography (CT) was in one case. MR imaging was with a i.5-T unit by using the techniques: sagittal Ti-weighted (SE) imaging (repetition time
msec/echo
time
two
acquired)
signals
the patients
at two major i99i and i994.
duration
scans,
Ankle, fractures,
The
on
METHODS
of four
insufficiency
Radiographs, Index terms:
male.
reviewed
images
records of all patients determine their age,
can
dancing, described
AND
recognized.
Specific
to
cal stress fracture is located in the talan neck and parallels the talonaviculan articulation. Atypical stress fractures of the lateral process of the talus have also been reported. The purpose of this study was to describe the clinical setting and pattern of talan insufficiency fracture as diagnosed with magnetic resonance (MR) imaging. Herein, we describe five talar insufficiency fractures, three of which were atypical in location and orientation and all of which occurred in four female patients. All fractures were diagnosed with MR imaging.
were pitals
fractures
related
running, All patients
orientation of talar insufficiency frachires is more variable than previously coexisting with MR
Talus:
msec
sion-recovery (STIR) time msec/echo time msec = i,400/20/i30)
=
and
400-500/i3-i6,
short
tau inver-
imaging (repetition msec/inversion time or fast SE proton-
density-weighted imaging pression (3,500-4,000/i7-i9
with fat [effective
supecho
timel, two signals acquired) and T2-weighted imaging (3,500-4,000/i02 [effective echo timel, two signals acquired); coronal Tiweighted SE imaging (500/i6, one signal acquired) and/or STIR (i,200-1,400/i3-20/ i30-i40) or gradient-echo (450/20, 45#{176} flip
angle, four signals acquired) imaging; and axial Ti-weighted (600/16, one signal acquired) and/or T2-weighted fast SE (4,000-5,250/102-i two signals thickness 0.0-1.0-mm
14 [effective
echo
time],
acquired) imaging. Section varied from 3.0 to 5.0 mm with gap. A 256 x 192 matrix and
12-i4-cm field cases. An insufficiency if a linear area
of view
was
used
fracture of diminished
a a
in all
was diagnosed signal inten-
was seen within the bone with variable surrounding marrow edema, manifesting as ill-defined low signal intensity sity
on
Ti-weighted
intensity pressed
images
and
high
on STIR, T2-weighted, proton-density-weighted
The
location
and
the
and
soft-tissue
and
orientation
presence
signal
or fat-supimages. of fractures
of concomitant injury
was
osseous
noted.
RESULTS All patients were women (age range, 37-70 years). All injuries nepresented insufficiency fractures. Two of the five talar insufficiency fractures were typical in location and orientation, occurring in the talar neck and oriented parallel to the talonavicular joint. Three of the five talar insufficiency fractures were atypical in location and onientation. Two occurred in the posteromedial talus; one was oriented vertically, and one was oriented horizontally. The remaining fracture was oriented horizontally in the body of the talus. A calcaneal stress fracture occurred ipsilateral to one of the two classically oriented talar neck fractures. In the patient with bilateral talar fractures, stress fracture of the distal tibia occurred on the same side as the atypically oriented talar fracture. All four patients had osteoporosis due either to disuse or age. One 37-
a
year-old patient was a housebound agoraphobic who developed left ankle pain exacerbated by ambulation
Abbreviations: tau
inversion
SE
=
spin
echo,
STIR
=
short
recovery.
439
a.
Figure
b.
2.
Atypical orientation and location of an insufficiency fracture in the left talus of the same patient as in Figure 1. (a) Coronal Ti-weighted SE MR image (400/16) demonstrates a horizontally oriented linear fracture of tow signal intensity in the posteromedial talus (arrow). (b) Sagittat T2-weighted fast SE MR image (4,000/102) demonstrates the talar fracture (arrowhead) and a concomitant stress fracture of the distal tibia (arrow) surrounded by high-signalintensity marrow edema.
after successful treatment with antidepressants (Figs 1, 2). Symptoms abated after 2 months of limited weight bearing and nonsteroidal anti-inflammatory therapy. The second patient was 39 years old and presented 3 months postpartum with left ankle discomfort that had been gradually worsening for the previous 10 months (Fig 3). An anthrotomy was performed for resection of subtalar spurs. The third patient was a 44-year-old file clerk who had experienced 2 years of left ankle pain exacerbated after a therapeutic trial of 2 months of non-weight bearing and cast removal. After confirmation of a horizontal insufficiency fracture of the body of the talus (Fig 4), the patient was placed on 8 weeks of bedrest and the symptoms resolved. The last patient was 70 years old and had experienced left foot and ankle pain for 1 month (Fig 5).
DISCUSSION Talar stress fracture (both insufficiency and fatigue) is often a clinically elusive diagnosis owing to its extremely low prevalence, as well as to the fnequently chronic and diffuse nature of the symptoms. The clinical findings often include a variable degree of soft-tissue swelling, erythema, point tenderness, and local pain. These findings are often relieved with rest and exacerbated 440
#{149} Radiology
with
continued
activity.
Limited subtalar motion often accompanies this injury (1). An association between talar stress fracture and pes planovalgus (2) and calcaneonaviculan coalition is recognized (i), although these abnormalities were not present in our series. A review of the literature since 1965 revealed 1 1 previously reported cases in 10 patients (six male patients; the gender in four patients was not specifled). Three typical talan neck fractunes, paralleling the talonavicular joint, were reported in two men (22 and 23 years of age; fracture was bilateral in the 22-year-old patient) during basic training (1) and in a 58-year-old male long-distance runner (3). Two atypical stress fractures of the lateral process were reported: an oblique fracture in a 52-year-old male tennis player (4) and a vertical fracture in a 20-year-old male long-distance runner (5). The French and German literature (6,7) had reports of five cases of talar stress fractures diagnosed with radionuclide bone scanning; the orientation and location in the talus were not identified. One fracture was reported in a male athlete (6), whereas gender was not specified in the nemaining patients (7). Conventional radiographs are usually normal in the acute stage of talar stress fracture (fatigue and insufficiency). In cancellous bone, the earliest plain radiographic sign of stress
b.
c.
Figure 1. MR images in a 37-year-old woman with a typically oriented tatar neck insufficiency fracture parallel to the talonavicular joint. (a) Axial and (b) sagittat TI-weighted SE images (400/16) demonstrate a linear fracture of low signal intensity (arrowhead in a, arrow in b) in the right tatar neck. (c) Sagittat T2-weighted fast SE image (3,500/102 [effective echo time]) demonstrates high-signalintensity marrow edema surrounding the hypointense linear fracture (arrow).
fracture is focal linear sclerosis, typically oriented perpendicular to the trabeculae (8). The linear sclerosis is thought to reflect collapse and condensation of trabeculae, endosteal callus, and osteoblastic new bone formation for the repair of trabecular microfracture, beginning approximately 3-4 weeks after the acute injury (9). Nuclear scintigraphy may demonstrate focal increased radiotracer uptake days to weeks before an November
1995
b. Figure 3. MR images in a 39-year-old woman 3 months posteromedial talus. (a) Coronal proton-density-weighted image (4,000/114), and (c) sagittal Ti-weighted SE image talus (arrowhead in b, arrow in c). The fracture extends
c. postpartum. The patient had a vertically oriented atypical insufficiency fracture fast SE image obtained with fat suppression (4,000/19), (b) axial T2-weighted (400/16) demonstrate the vertical low-signal-intensity fracture at the posteromedial to the subtalar articutar surface (arrow in a).
a.
a.
b.
Figure tally body
4.
(a) Sagittal
oriented atypical in a 44-year-old
high-signal-intensity
and
(b) coronal
insufficiency woman. The marrow
STIR MR images fracture fracture
(arrow has low
(1,400/20/130)
in a, arrowhead signal intensity
because capability
not necessarily sensitive for diagnosis. On MR images, a fracture in cancelbus bone manifests as an irregular linear area of low signal intensity with all pulse sequences with variable surrounding bone marrow edema (iO). MR imaging is superior to CT
pattern sclerosis
197
#{149} Number
a horizontalar by
edema.
abnormality is discernible at plain radiography. The sensitivity of scmntignaphy is compromised by a lack of specificity: Similar increased radiotracer uptake may be encountered in entities such as osteomyelitis and neoplasm. In general, targeted thin-section CT (with bone algorithm) may allow specific detection of trabeculan fracture and disorganization but is
Volume
demonstrate
in b) through the and is surrounded
2
it has multiplanar imaging and provides exquisite conspicuity for bone marrow edema and soft-tissue detail. MR imaging may also be more sensitive than bone scmtigraphy in the early diagnosis of fractune, particularly in the setting of severe osteopenia (ii), advanced age or renal insufficiency In the talus, the classic
(12),
of stress fracture perpendicular
(i3). radiographic is a linear to the trabecu-
lan flow (1), paralleling the talonaviculan articulation at the talar neck (Fig 1). This classic pattern, however, was present in only two of our patients. Two case reports describe stress frac-
of the fast SE
tune of the lateral process of the talus in athletes; both cases were diagnosed with CT (4,5). Increased supination of the foot while running was hypothesized to be the reason for a concentration of forces on the lateral process of the talus (4). To our knowledge, vertically and horizontally oriented insufficiency fractures of the medial aspect of the posteroinfenion talus (Figs 2, 3) or transverse (horizontal) fractures of the talar body (Fig 4) have not been previously reported. Five of the previously reported 1 1 cases relied on bone scintigraphy; therefore, the location and orientation of the fracture could not be determined (6,7). These atypically oriented talar insufficiency fractures may remain occult on plain radiographs due to overlap of osseous structures, particularly in the region of the posterior subtalar joint and middle talocalcaneal facet. Coexisting or preexisting stress fractures of the distal tibia and calcaneus
may
occur
in
either
the
ipsi-
lateral or contralateral limb and were observed in half of our patients. Recognition of the various locations and orientation of talar insufficiency fractures is especially important in this era of cost containment, in which patient tion
“throughput” of
imaging
and time
the
(usually
neducby
limit-
ing various planes of evaluation per patient) are emphasized. It is important to perform two sequences in orthogonal planes to diagnose this injury, as the fracture could be missed if the plane of imaging is oriented parallel to the fracture plane. Radiology
e
441
:
.
4i:
;.,
,%
a.
b.
Figure the
5.
(a) Sagittal
tatonavicutar
ture
joint
of the ipsilateral
oriented
calcaneus
talar
TI-weighted (arrowhead).
catcaneus
insufficiency
(arrow).
SE MR image
Both
(b) Sagittat
(arrow).
fracture
fractures
c.
(549/14)
in a 70-year-old
proton-density-weighted
(c) Conventional
(arrowhead)
are linear
Although an atypical appearance of a common entity might not prove diagnostically elusive, an unusual manifestation of an uncommon entity might further delay a correct diagnosis. Clinical familiarity with this often nadiographically occult entity and the use of MR imaging to allow early, specific diagnosis of talan insufficiency fracture and coexisting injuries may prevent delayed diagnosis and unnecessarily prolonged patient morbidity. The pattern of talan insufficiency fractures is more variable than that of previously reported fatigue fractures. The location and orientation of the talar insufficiency fractures described as atypical in this series may actually be a “classic” finding of talar insufficiency fractune that is not yet recognized. #{149}
fast
lateral
parallel
areas
woman
to the
of sclerosis
radiograph
obtained joint
(3,500/19)
6 weeks and
perpendicular
the
5.
Assoc
Motto process Sports Black
the
1983;
concomitant
KP,
Ehlert
KJ.
process
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7.
stellenwert
sketettszintigraphie.
10. 11.
of
in a runner. 13.
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