Ultrasound as a
primary evaluation tool of bone stress injuries in elite track and field

A., Maliaropoulos N., Tsitas K., Kiritsi O., Padhiar N., Del Buono A., Maffulli
N. American Journal of Sports Medicine, 2012; 40: 915-919

injuries, specifically bone stress injuries are a problem in elite track and
field athletes and often go misdiagnosed or not diagnosed at all. Though
magnetic resonance imaging (MRI) is the gold standard method to diagnose a bone
stress injury, it is costly. Therapeutic ultrasound (TUS) may be a
cost-effective and noninvasive tool for preliminary diagnosis of stress
fractures. Therefore, the purpose of this study was to determine if TUS is an accurate
method for early diagnosis of bone stress injuries compared to MRI. This was a
ten-year study that assessed 113 (53 males and 60 women) elite track and field
athletes, who were suspected of a bone stress injury. These patients had less
than 1 month of unilateral exercise induced pain that alleviated with rest, and
had no history of lower leg trauma. Athletes with suspected muscle strain,
compartment syndrome, or low back pain were excluded. Bilateral examinations
were performed by an experienced physical therapist using a TUS device. TUS (5
cm2 probe, 1 MHz) was conducted at the site of pain with continuous
ultrasound at highest intensity (2 W/cm2) and the most symptomatic
point was spotted for 30 seconds (probe was moved at 1 cm/s). Patients were
separated into 2 groups: 1) pain with TUS intensity and 2) no pain with TUS
intensity. MRI scans were also used for suspected bone stress injuries. The
authors scored the MRIs using a 5-stage grading scale to classify bone stress
injuries (e.g., 0 = normal appearance, 3 = stress fractures with discrete
fracture line visible). An independent radiologist blinded to athletes’
clinical features and TUS exam analyzed the imaging reports randomly. The
distal tibia followed by the metatarsals were the most common sites of injuries
[n = 42 (51%), n = 25 (21%), respectively], the least common site of injury was
the femoral neck [n = 1 (1%)]. The MRI results showed that 2.7% had a 0 grade
injury, 10.6% had a grade of 1 injury, 13.3% had a grade 2 injury, 68.2% had a
grade 3 injury, and 5.3% had a grade 4 injury. Compared to MRI, TUS showed 95% sensitivity (sensitivity:
positively diagnose a patient who has pathology) for high-grade injuries (i.e.,
MRI bone stress injury scale of 3 or 4), and 44% sensitivity for low-grade bone
stress injuries (i.e., MRI bone stress injury scale of 1 or 2). The TUS was
shown to have 66.6% specificity (specificity: not
falsely diagnosing a healthy patient) and 99% positive predictive value
(precision rate or proportion that a positive test correctly diagnosis a
patient), 13.4% negative predictive value
(proportion of subjects that a negative test result correctly diagnosis a
patient), and 81.4% accuracy compared to the MRI as the gold standard.

gold standard for diagnosing possible bone stress injuries is the MRI; however,
this can be very costly. TUS is more cost efficient and more readily available
than the MRI. The TUS was shown to be sensitive for the diagnosis of bone
stress injuries compared to MRI; particularly more severe bone stress injuries.
Therefore, TUS could be useful in the assessment of bone stress injuries.
Physical therapists as well as athletic trainers can perform TUS if the
clinician suspects the presence of a stress fracture, which could help early
diagnosis of bone fractures. Earlier detection of stress fractures could lead
to earlier return to sport activity. Since most of the injuries (~75%) were a
grade 3 or 4 this could have led to an increase in the sensitivity of TUS since
it is easier to identify the more serious injuries. It is important to note
that TUS missed many low-grade MRI-detected stress injuries so it is important
for clinicians to carefully monitor patients with possible low grade stress
injuries and negative TUS findings. Further research with TUS will be needed to
determine the reproducibility (reliability), as well as methodology to increase
sensitivity. TUS may be used as the first tool in the evaluation of suspected
overuse bone injury but with caution since TUS has a low ability to pick up
less severe bone injuries. Do you have a TUS in your athletic training room and
feel confident that you could use it as a tool for the diagnosis of early bone
stress injury?

by: Jane McDevitt MS, ATC, CSCS
by: Jeffrey Driban


Papalada A, Malliaropoulos N, Tsitas K, Kiritsi O, Padhiar N, Del Buono A, & Maffulli N (2012). Ultrasound as a primary evaluation tool of bone stress injuries in elite track and field athletes. The American Journal of Sports Medicine, 40 (4), 915-9 PMID: 22366519