Page 338 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Musculoskeletal system: 1.8 Soft-tissue injuries 313

VetBooks.ir SUPERIOR CHECK LIGAMENT The latter allows tenoscopic-guided removal of
(ACCESSORY LIGAMENT OF
extruded damaged ligament material to leave a
THE SUPERIOR DIGITAL FLEXOR
TENDON) DESMOPATHY smooth surface. In addition, PRP and/or cultured
stem cells have been injected into the residual deeper
disrupted region of the ligament under tenoscopic or
Definition/overview ultrasound guidance.
The AL-SDFT (or ‘superior check ligament’) is a If the lesion is isolated, the prognosis is good for
strong ligamentous structure that arises from the return to full function, as this amounts to a des-
palmar medial aspect of the distal radius and joins the motomy. The prognosis is much poorer if the lesion
SDFT near its myotendinous junction proximal to, extends into the SDFT.
or at the level of, the proximal aspect of the accessory
carpal bone. It forms the medial wall of the carpal SUSPENSORY LIGAMENT
flexor tendon sheath in the distal antebrachial region. DESMOPATHY (‘DESMITIS’)
Injury to this ligament is rare and appears to be
always associated with secondary tenosynovitis of Definition/overview
the carpal sheath, even though it is not technically The SL has been defined as a ligament but is in fact
within the sheath confines. It may be secondary to a muscle (interosseous III) whose muscle fibres have
SDFT injury or occur spontaneously. atrophied for the most part, although a few actually
remain in the proximal portion, especially in young
Aetiology/pathophysiology animals (residual muscle fibres tend to atrophy with
The aetiology is unclear and may be related to over- age). SL desmitis is therefore a form of tendon dis-
extension of the carpus while the SDFT is under ease, similar to SDF tendinopathy, and is the second
load. It may also be secondary to proximal extension most common site for tendon and ligament injuries in
of an SDFT tear. the horse. It is encountered in all breeds but is most
common in the forelimbs of racehorses and in both
Clinical presentation fore- and hindlimbs in Standardbreds. It is, however,
The clinical signs are not specific but include acute- increasingly recognised in the hindlimbs of sports
onset lameness, swelling of the carpal sheath and horses. The terminology has not been addressed as well
pain and swelling on the distocaudomedial aspect of as for the SDFT but although ‘desmitis’ ( inflammation
the antebrachium. of a ligament) remains the usual term employed,
‘ tendinopathy’ should really also be used and desmopa-
Diagnosis thy is becoming increasingly favoured. The condition
Diagnosis is made ultrasonographically by imag- differs depending on the site of the lesion and has been
ing an enlarged, hypoechogenic and heterogeneous divided into proximal desmopathy (affecting the origin
AL-SDFT. There may be complete rupture with [i.e. the bony origin and proximal 3–5 cm of the SL]),
haematoma formation between the ruptured ends. desmopathy of the body (from the origin to the bifur-
In acute cases haemorrhage may be visible in the cation) and desmopathy of the branches.
sheath or there may be marked oedema and sheath
distension. The whole SDFT should be assessed to Aetiology/pathophysiology
look for other lesions. Tenoscopy of the carpal sheath The aetiology is similar to that of SDF tendinopathy,
can identify lesions that involve the sheath and tears involving repeated, cyclic stain. It is unclear, how-
have been reported most often caudally through the ever, under which circumstances the SL is affected
thickest part of the ligament. rather than the SDFT and why it should affect a
specific portion of the ligament. Branch injuries may
Management/prognosis be occasionally associated with a single excessive or
Treatment recommendations include rest, carpal asymmetrical weight-bearing event. Some branch
sheath medications and tenoscopy of the sheath. injuries are also associated with sesamoid bone