The authors present a case report of a torn DBT as an example of the application of MSUS.
is a Senior Staff Radiologist in Muskuloskeletal Radiology, in
the Department of Diagnostic Radiology, Henry Ford Hospital,
is a Musculoskeletal Radiologist with Medical Imaging of Denton,
Rupture of the distal biceps tendon (DBT) is a rare occurrence
and is usually associated when a sudden force is applied on a
flexed elbow. Often challenging to evaluate clinically, urgent
diagnosis is necessary for prompt repair of the distal biceps to
preserve function and flexibility at the elbow. Although magnetic
resonance imaging (MRI) has been the mainstay of diagnosis in this
arena, musculoskeletal ultrasound (MSUS) is increasingly being
recognized as an efficacious modality to diagnose not only the
presence of a tear in the DBT, but also its extent and the degree
of retraction. The authors present a case report of a torn DBT as
an example of the application of MSUS.
A 50-year-old man presented with a bruised distal biceps area
following a lifting injury. He had felt a "pop" with a subsequent
swelling, bruising, and pain over the distal left arm and elbow.
Physical examination revealed an asymmetrically enlarged and tender
distal left arm (the "Popeye" sign) with diminished strength in
flexion and supination at the elbow.
The patient was evaluated with an Antares ecograph
(Siemens-Acuson, Mountain View, CA) using a 5- to 13-MHz linear
array transducer. The images were reviewed on a generic picture
archiving and communication system (PACS). Only soft copy images
were used for interpretation, annotation, and illustration.
The MSUS images were obtained following the protocol established
in our institutions for routine exploration of the elbow. Long-axis
and short-axis views of the DBT were obtained with the elbow in
extension and, simultaneously, the wrist and hand in
hypersupination. The bony acoustic landmarks of the radial head,
neck, tuberosity, distal humeral condyles, and brachial artery were
used for orientations in long- and short-axis evaluations.
Additional images in nonorthogonal planes and color Doppler images
were obtained to optimize the separation of the brachial artery
from the intimately adjacent DBT. Short-axis images at the level of
the radial tuberosity with the elbow in full-flexion and wrist in
flexion-pronation were also obtained for visualization of the DBT
insertion onto the radial tuberosity.
Routine MSUS images of the symptomatic elbow of the patient
demonstrated a large hypoechoic collection of abnormal fluid over
the antecubital fossa, representing a hematoma (Figure 1). The DBT
was completely torn, retracted, and coiled over the brachialis
muscle, and surrounded by capacious hematoma (Figures 2 and 3).
There was an interruption of the fibrillar pattern of the tendon
insertion into the radial tuberosity (Figure 4). A small residual
stump or flap of the tendon at the radial tuberosity was noted.
There was no bony avulsion fragment from the radial tuberosity. The
elbow joint had no effusion.
The ultrasound images were diagnostic of a completely ruptured
DBT, corroborating the clinical examination. The orthopedic
surgeons recommended surgery to repair the tendon, but the patient
has not yet decided to have it.
Rupture of the DBT is an uncommon musculoskeletal injury,
representing <5% of all biceps tendon injuries of the arm. It is
usually seen in men 40 to 60 years of age who are manual laborers,
construction workers, athletes, or weight lifters. The injury most
frequently occurs during heavy lifting with the elbow flexed 90° or
when the biceps muscle contracts suddenly and forcefully against
unexpected resistance. Occasionally, spontaneous ruptures can occur
without a specific history of trauma.
The dominant arm is more commonly affected.
Early diagnosis of this injury, differentiation of partial from
complete rupture, and measurement of the degree of retraction are
important in planning patient management.
The clinical diagnosis of DBT injury may be challenging in
partial tear, nonretracted complete tear, or brachialis tendon
injury. Swelling or edema obscures the tendon defect, and palpable
thickened lacertus fibrosus may also lead to a misdiagnosis of an
intact tendon. Differentiation of partial versus complete rupture
is important since complete ruptures generally require surgical
repair, while partial ruptures are traditionally treated
conservatively. Two weeks following the injury, scarring and
retraction of the tendon make the surgery more difficult, so early
diagnosis is important.
Although magnetic resonance imaging (MRI) has been the mainstay
of diagnosis in this arena,
musculoskeletal ultrasound (MSUS) is increasingly being recognized
as an efficacious modality to diagnose not only the presence of a
tear in the DBT, but also its extent and the degree of retraction.
The authors report this case of a torn DBT as an example of the
application of MSUS.
With ultrasound, the direct signs of complete rupture are
nonvisualization of the distal biceps tendon with fluid collection
or hematoma (Figures 1 to 3) within the tendon sheath or gap, along
with truncated proximal (Figure 2) and distal stumps of the
retracted tendon. Granulation tissue or hematoma within the tendon
sheath or irregular synovial thickening of the tendon sheath may
mimic preserved strings of tendon substance, leading to the
underdiagnosis of a partial rupture. However, total loss of the
fibrillar pattern and irregular nodular appearance of the
granulation tissue or synovial thickening are additional findings
that help to avoid this pitfall (Figure 4). Sometimes the distal
brachial artery adjacent to the biceps tendon may be confused with
the hematoma. Weakly pulsatile or heavily compressed brachial
artery (Figure 4) requires Doppler angiography.
Complete tears are more common than partial tears. Tears almost
always occur at or near the distal insertion site on the radial
tuberosity, with variable retraction from the radial tuberosity.
Longitudinal intratendinous tears or shearing type tears can also
occur, and these have been recognized with MSUS imaging.
Partial ruptures show thinning (attrition of tendon substance,
usually chronic) or thickening (from tendin-opathy or granulation
tissue) of the distal biceps tendon. As in a complete tear, fluid
or hematoma within or adjacent to the partial rupture can occur,
but the tendon remains contiguous along its course.
This case illustrates the efficacy of ultrasound in clearly
demonstrating the torn and retracted DBT, with the torn end lying
over the brachialis muscle. The large hematoma separating the
retracted end and the residual stump were depicted accurately.
High-frequency transducers provide high-resolution images, readily
delineating the fine details of the injured tendon. In addition,
the extended field-of-view technique was useful in providing a
panoramic view of the injury while demonstrating the level of
Furthermore, MSUS has several other advantages over other imaging
modalities: it is inexpensive, rapid, noninvasive, and does not
require ionizing radiation. Dynamic motion study is easy to
perform, and direct blood flow mapping is possible with color or
power Doppler techniques. Comparison with the asymptomatic side is
easier when necessary. The three-dimensional imaging technique, now
available in many US machines, may also prove to be a useful
The torn DBT in a patient with elbow trauma was clearly
visualized with MSUS as a coiled and retracted tendon, avulsed from
the radial tuberosity, and separated by a large hematoma. MSUS was
useful in confirming the clinically suspected DBT rupture,
characterizing it as a full-thickness tear, and assisting in the
patient management. *