Page 313 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition
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288                                        CHAPTER 1



  VetBooks.ir    1.8  Soft-tissue injuries



           Soft-tissue structures, including tendons and   The prognosis is guarded to poor and an early, accu-
           ligaments but also their synovial sheaths and   rate diagnosis is paramount to improve the chances
           other connective tissue elements, are major    for recovery.
           components of the musculoskeletal system.        Most of these soft-tissue injuries appear to have a
           While bones are the main supporting struc-     similar pathophysiology based on repeat, cyclic and
           tures, muscles, ligaments and tendons are under   overuse trauma or, less commonly, direct trauma to
           significant stress in athletic animals. Soft-tissue   the limb.
           injuries are consequently extremely common.
           The advent of ultrasonography and, more        DIAGNOSTIC TECHNIQUES
           recently, of MRI has enabled us to recognise
           an increasing variety of conditions, while there   Localisation  of  the  site  of  pain,  in  some  cases  by
           probably remains many more still to discover.  regional or intrasynovial anaesthesia, is important as
             Many soft-tissue injuries heal slowly and    soft-tissue injuries are subtle and difficult to detect
           poorly, often with significant loss of func-   using observation and palpation alone. Furthermore,
           tion. This is a source of major losses in the   there is often significant regional oedema, making
           equine industry. New approaches to therapy are   precise location of a lesion difficult. The clinician
           emerging, bringing hope of a better and faster   must also be aware that obvious alterations are not
           recovery, although they are very much in their   necessarily clinically significant or at least not the
           infancy.                                       cause of the current lameness.

           TYPES OF INJURY                                Ancillary diagnostic techniques
                                                          Radiography
           Horses are particularly prone to tendon injuries   Radiographic examination may be useful to rule
           because of their weight, the extreme anatomical   out concurrent or associated bony/articular abnor-
           simplification of their distal limb and the speed at   malities (e.g. fractures, splints) but also to look for
           which they can work, all of which combine to induce   abnormal bone reaction (e.g. sclerosis, new bone
           enormous loading on tendon and ligament struc-  formation, entheseopathy) at the tendon or ligament
           tures. Injuries to the superficial digital flexor tendon   insertion sites.
           (SDFT) and the suspensory  ligament  (SL)  are the   Positive contrast bursography, tenosynoviogra-
           most common and affect a large number of race and   phy or arthrography may be useful in some cases,
           sports horses. There is, however, a much wider range   to  ascertain  communication  between  fluid-filled
           of tendon and ligament conditions and it is increas-  cavities (e.g. between joint cavities, tendon sheaths
           ingly clear that most limb soft-tissue structures can   and bursae) or to look for subtle fistulas. Injection of
           be involved in either traumatic or degenerative injury.   an iodinated, positive-contrast material into a given
           The diagnostician must therefore acquire an increas-  synovial cavity, through an area devoid of infected
           ingly thorough knowledge of soft-tissue limb anat-  material, may show leakage of the fluid through a
           omy and the use of specific diagnostic techniques.   wound  or  opacification  of  another  synovial cav-
             Disorders affecting articular and periarticular   ity with which it does not normally communicate
           ligaments,  capsular  structures  and  muscle  injuries   (Figs. 1.545, 1.546).
           will be dealt with elsewhere.
             Tenosynovitis  (inflammation  of  tendon  sheaths)  Ultrasonography
           is commonly recognised in all types of horse and   Ultrasonography can be used to examine all soft-tis-
           pony. The complexity of the underlying pathology   sue structures, as long as they are not separated from
           of these cases is becoming increasingly understood.   the skin by bone or gas. This includes the insertions
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