Page 333 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

308 CHAPTER 1

VetBooks.ir 1.595 1.596

Figs. 1.595, 1.596 Chronic tendinopathy leads to a mixture of subacute tears interspersed with scar
tissue. (1.595) On cross-section, the tendon is severely enlarged (double arrow in 1.596), heterogeneous with
hyperechogenic areas and variably hypoechogenic foci (arrow). (1.596) On longitudinal images, hypoechogenic
lesions, devoid of striation, dissect between hyperechogenic scar tissue. Active peritendonitis causes thickening
of the paratenon (p).

in chronic cases, causing hyperechogenic interfaces of the severity score or more than 20% of the total
casting an acoustic shadow. This is often considered tendon CSA at any level are indicators that the work
to be a poor prognostic sign. programme is too intense. Return to more intense
work (i.e. canter or galloping) should not be advised
Follow-up of injuries if the echogenicity has not returned to near normal
Ultrasonography should be used regularly (every and the fibre alignment score has not improved dra-
8–12 weeks) to monitor the progress and quality of matically (i.e. 0 to 1).
healing, looking for variations in CSA as described
above, increases in echogenicity (fibrous tissue for- Doppler ultrasound
mation) and improvement of fibre alignment on This may be used to assess vascularisation of tendon
longitudinal scans (Figs. 1.597–1.600). Adequate during the healing process (Fig. 1.601). It is car-
healing is characterised by stabilisation, or even ried out with the limb held up in partial flexion. The
reduction, of tendon CSA, isoechogenicity of the technique, however, requires experience as inad-
damaged portion with normal tendon tissue and fair equate settings and the presence of artefacts render
longitudinal alignment of the replacement fibres. interpretation difficult. Normal tendon contains
This follow-up is important to evaluate the quality very small vessels, not detectable on colour flow or
of healing and its adequacy with return to work, but power Doppler imaging. Abnormal vascular flow
also the risk of recurrence/chronicity. The workload may be present either in immature scar tissue or in
during the rehabilitation period should be kept the chronic, poorly organised fibrous tissue. It is most
same or reduced if tendon total CSA or lesion size useful to detect chronically active lesions that con-
increases, even slightly. Increases by more than 10% tain numerous, large calibre vessels.