Page 336 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Musculoskeletal system: 1.8 Soft-tissue injuries 311

VetBooks.ir Close monitoring with regular ultrasound examina- administered as early as possible, before the lesion
becomes too organised. Their aim is to improve
tions helps to optimise this regime. Gradual return
to training should not be reinstituted for at least
mechanisms, either by altering local cell synthetic
4–6 months, still under ultrasonographic guidance. healing tissue quality through various biological
A controlled exercise programme is summarised metabolism or by supplying cells capable of pro-
below: ducing near-normal tendon matrix (i.e. stem cells).
Intralesional or peritendinous injections of poly-
• Walking for 30 minutes daily for 4 weeks sulphated glycosaminoglycans and hyaluronic acid
(in-hand or in walker or treadmill). have been disappointing. Corticosteroids are likely
• Then walking (in-hand, walker or under saddle) to be deleterious because of inhibition of repair
45 minutes daily for 4 weeks. mechanisms. Intralesional injection of growth fac-
• Follow-up ultrasonographic examination at tors has been attempted. Among these, insulin-like
8 weeks, then every 8 weeks or prior to changes growth factor-1 has been shown to provide some
in exercise level. gain in vivo in terms of speed of repair, but this may
• Add 5 minutes trotting to above for following be mainly through increased scar tissue production.
4 weeks, then 10 minutes trot over the following Intralesional, autologous platelet-rich plasma (PRP)
4 weeks. is increasingly used, both in horses and humans, to
• Gradually add slow canter (15–20 minutes daily) treat tendon and ligament injuries. There is a pleth-
over 4–12 weeks depending on severity of injury ora of commercial kits available to produce PRP
and sonographic appearance. from venous whole blood. However, the growth
• At that stage (4–6 months), either turn out to factor concentration of the PRP obtained and the
pasture for 3–6 months or, preferably, continue degree of contamination with undesirable red blood
controlled exercise as follows: canter one mile cells or WBCs varies tremendously.
daily for 4 weeks, two miles daily for a further Few objective studies are available but a recent
4 weeks. blind-controlled study of naturally occurring SDF
• Reintroduce normal training gradually. tendinopathy showed significant improvement over
controls at 12 months post injury, although there
No cantering or galloping should be allowed was little difference on follow-up at 24 months.
before 6 months after injury, as re-sprain is likely Sternebral or iliac wing bone marrow has been
unless the injury is mild. The protocol should be used as a source of growth factors and/or stem
altered depending on the severity of the injury cells. There is little published evidence regarding
(increase exercise regime earlier if the lesion is mild its benefits and there are increasing concerns about
and sonographic appearance indicates adequate potential adverse effects (i.e. large volume required,
repair; delay if severe and sonographic appearance presence of blood cells, differentiated stromal cells,
shows poor healing). large amounts of fat and bone material, small or
Return to racing/competing should be envisaged even negligible percentage of stem cells). Progenitor
at 9–12 months, depending on the severity of the stems cells are the most fashionable therapeutic
injury and ultrasonographic evolution at follow-up option currently in human and veterinary medicine.
examinations (see Ultrasound). These cells are capable of producing most cellular
types. Embryonic stems cells are most promising
Intralesional treatments but there are still major difficulties in producing
A number of biological treatments have been under sufficient quantities and controlling their differ-
evaluation or advocated for clinical use in recent entiation into the required cell type in vivo. There
years, although there is still little consensus on their have also been reports of induced neoplasia at the
actual effectiveness. Various molecules or biological site of injection. Mesenchymal stem cells (MSCs)
preparations are injected into the lesion under ultra- are less pluripotent but are capable of producing
sonographic guidance. These treatments are best chondro-, osteo-, fibro- or tenoblasts. The lifespan