Diagnostic ultrasound ( PDFDrive )

CHAPTER 23 Overview of Musculoskeletal Ultrasound Techniques and Applications 861
A
B
C
FIG. 23.9 Tendinosis. (A) The long-axis image of the
mid Achilles tendon demonstrates fusiform, hypoechoic
swelling of the tendon (arrowheads), although the ibrillar
architecture can still be discerned. (B) In short-axis view,
the Achilles appears thickened and is ovoid in morphology
(arrowheads). (C) In a different patient, the Achilles tendon
at the insertion on the calcaneus is thickened and hypoechoic
with loss of the normal ibrillar pattern (arrows). There is
marked hyperemia on color Doppler imaging. Note the dorsal
calcaneal enthesophytes (arrowheads). C, Calcaneus.
which can be visualized on Doppler ultrasound in tendinosis
but not in normal tendons. 18
Tendinosis is common in the Achilles tendon, where it most
commonly afects the midportion of the tendon, or “watershed,”
where there is overlapping blood supply. Tendon degeneration
can also occur at the bone-tendon interface or enthesis, seen in
the Achilles as insertional tendinosis at the calcaneus. Tendinosis
at the tendon-bone interface is the most common pattern of
degeneration seen in the common lexor and extensor origins
at the medial and lateral humeral epicondyles at the elbow, forming
part of the clinical spectrum of epicondylitis. Similar to tendinosis
elsewhere, insertional tendinosis or enthesopathy is characterized
by tendon expansion and hypoechogenicity. 19,20 Enthesitis, or
inlammation at the enthesis, can occur in patients with rheumatoid
arthritis, psoriatic arthritis, or spondyloarthropathy. he
imaging features of enthesitis can overlap with tendinosis, with
tendon expansion and hypoechogenicity, but neovascularization
may be a more prominent feature and bony erosion may also
be present. 21,22
Patients with tendinosis are more prone to tendon tears.
Tendon tears may be partial or complete. Partial tears may be
transversely oriented (parallel to the short axis of the tendon)
or longitudinally oriented (parallel to the long axis of the tendon,
also referred to as a “longitudinal split tear”). Tears are manifested
by anechoic or hypoechoic clets, with focal tendon iber
discontinuity 23 (Fig. 23.10). When a complete rupture occurs,
the tendon ibers are entirely discontinuous and some degree of
tendon retraction may occur because of now-unopposed muscle
contraction (Fig. 23.11). he extent of retraction is of importance
for surgical planning and thus should be measured. In an acute
tear, there may be complex luid and hematoma within and
about the tear site. When evaluating lexor and extensor
tendons at the hand and wrist, passive and active motion can
facilitate accurate identiication of the tendon of interest and
can provide mechanical correlation for the integrity of a tendon
(Video 23.3).
Sonographic Signs of Tendon Tears
Discontinuity of ibers (partial or complete) with
hypoechoic or anechoic gap
Focal thinning of the tendon
Hematoma (usually small)
Bone fragment (in cases of avulsion)
Nonvisualization of retracted tendon (in complete tear)
In tendons with surrounding tendon sheaths, inlammation
of the tendon sheath (tenosynovitis) may occur as an overuse
phenomenon or as a result of an inlammatory condition, such
as rheumatoid arthritis. Tenosynovitis is manifest on ultrasound