Page 724 - Adams and Stashak's Lameness in Horses, 7th Edition

690 Chapter 5

around the ST requires constant manipulation of the Treatment of acute tenosynovitis should include rest,
scan head for proper evaluation of the architecture NSAID therapy, and cold therapy. Intrathecal injection
VetBooks.ir The chestnut can interfere with scan head footprint lim- help resolve acute synovitis, but corticosteroids should
of hyaluronan and short‐acting corticosteroid should
throughout its course on the medial aspect of the limb.
be used with caution if tendon damage is found or sus-
iting interpretation of the LDFT at this site. Longitudinal
tears in the LDFT and superficial fraying of the tendon pected. If inflammation and lameness continue (espe-
are the most common types of lesions detected via ultra- cially in the event that no structural damage can be
sonography and should not be confused with prolifera- found) but particularly if bone or tendon damage is
tive synovial hyperplasia of the TS. The LDFT may be documented, tenoscopy of the TS is indicated.
examined from the plantaromedial aspect of the tarsus Accurate treatment of these chronic problems
and is a large oval‐shaped structure with well‐defined involves tenoscopic exploration to assess the specific
margins. The dorsolateral aspect of the tendon may pathology that exists. 26,47,123,124,145,147 Lesions of the TS
appear slightly less echogenic than the remainder of the and LDFT and fragmentation of the ST are visible
tendon, and care should be taken not to misinterpret with tenoscopy and can be addressed directly with this
this as a lesion. Sonographic examination infrequently technique. Debridement of the damaged tendon is
visualizes associated tendon injury. Primary lesions of most effective when the tendon injury is peripheral
the LDFT in the tarsal region are rare but do occur in and associated with tendon fiber fraying. Distension
mature horses. 32 of the sheath is often resolved when the tendon is
In addition to the standard radiographic views of the appropriately debrided. Synovial masses and fibrous
tarsus, the skyline and flexed lateromedial projections adhesions can be identified and resected. Fragmentation
should be included to emphasize the ST and plantar of the ST is best managed with fragment removal and
regions of the tarsus. Acute injuries such as fracture(s) of fracture site debridement via tenoscopic technique. If
the ST may be identified. More chronic diseases create the fragments are outside the retinaculum on the
destructive and/or proliferative changes to the ST and medial aspect of the ST, they can be removed by mak-
may appear as mineralization of the LDFT, the long ing a separate extrasynovial incision directly over the
plantar ligament (LPL), and parts of the TS. Contrast fragment.
radiography/tenography can be useful to evaluate the The prognosis of horses with TS tenosynovitis is vari-
position and shape of the TS and allow some delineation able and quite dependent on the cause. Horses with idi-
of the LDFT, but this technique is rarely utilized. opathic synovitis have a very good prognosis except for
Contrast radiography/tenography or contrast fistulog- the cosmetic blemish. Horses with small fractures of the
raphy may help to identify foreign bodies. ST can do well, provided damage to the LDFT is mini-
TS effusion can occur due to a variety of soft tissue mal. However, chronic changes associated with fracture
and bony injuries. Acute TS effusion usually occurs uni- of the ST have been associated with a poor prognosis for
laterally, with sudden onset of moderate to severe lame- return to athletic soundness. 47
ness. Acute tenosynovitis of the TS is most often due to
a traumatic insult to the medial aspect of the tarsus. The Septic Tenosynovitis of the Tarsal Sheath
medial edge of the ST is a prominent structure on the
medial aspect of the tarsus and is prone to fracture from Lacerations and puncture wounds on the medial
direct trauma. Overstretching of the sheath may cause aspect of the tarsus can be highly problematic. Soft tis-
aseptic tenosynovitis of the TS. Intrathecal hemorrhage sue swelling often accompanies these injuries, making
from synovial trauma induces marked inflammatory an early accurate diagnosis difficult. Lameness is often
response, and it can lead to formation of restrictive quite severe particularly when the puncture wounds
intrasynovial adhesions. Lameness that develops in these heal over quickly. The size, depth, and direction of the
animals may be due to the formation of intrathecal wound can affect many vital structures. The potential
adhesions. In the event of a fracture of the ST, the LDFT for the involvement of any of several synovial structures
may be unaffected if bone damage is confined to the dictates that a careful evaluation be performed.
medial edge of the ST, but larger fractures can disrupt Contaminates such as hair and/or debris may be driven
the fibrocartilaginous gliding surface. deep into the wound providing a nidus for infection.
Horses with lameness thought to be associated with Wounds that have bony involvement (fragmentation) of
chronic unilateral TS effusion should have thoroughly the tarsal groove of the ST can cause severe lameness
investigated with US and radiography. Common find- due to the motion of the LDFT against the roughened
ings visible on US include synovial proliferation, intrath- bone even without infection (Figure 5.92). In addition
ecal hemorrhage, adhesions, fibrous masses, and the tarsal retinaculum can act as a constricting band
mineralization/calcification within the TS wall. US when the LDFT or TS is inflamed and swollen. Other
examination may demonstrate fibrillation of the LDFT, bony abnormalities such as osteomyelitis or sequestra of
or more severe architectural changes include enlarge- the ST or calcaneus can also be associated with wounds
ment and/or hypoechoic areas consistent with tendon to the tarsus and can further complicate treatment.
injury. Mineralization in the LDFT and the surface of Clinical pathological analysis of synovial fluid and
the ST does occasionally occur. Radiographically, new diagnostic imaging are necessary to determine what
bone proliferation can be seen in the region originating structures are affected and the necessary treatment(s).
from the original trauma or possibly in response to Early diagnosis and aggressive treatment are critical for
chronic tendon sheath distension. Mineralization may a successful outcome. Septic synovitis is best treated
also occur within the LDFT and is felt to be a poor prog- with a combination of systemic antimicrobial therapy,
nostic indicator. joint lavage, and/or regional intravenous perfusion with