Page 568 - Adams and Stashak's Lameness in Horses, 7th Edition

534 Chapter 4

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Figure 4.114. Transverse proton density MRI image showing
high signal intensity (arrow) in the lateral branch of the oblique DSL
in the pastern region.

Figure 4.113. Enthesophytes on the palmar lateral cortex of P1 DSLs. Currently, MRI is the best diagnostic tool to make
can be seen on this DLPMO radiograph of the pastern. The clinical a definitive diagnosis (Figure 4.114). 58,61 See Chapter 3
significance of these lesions is questionable but may suggest a for additional information on MRI.
previous injury at the insertion site of one of the DSLs or far less
commonly the insertion of the distal digital annular ligament (DDAL). Treatment
This horse was sound and radiographs were taken as part of a
prepurchase examination. In general, injuries to the DSLs are treated very simi-
larly to other soft tissue problems such as tendinitis. In
acute cases, confinement, cold therapy, pressure/support
disruption, discrete core lesions, and periligamentous wraps, and administration of NSAIDs are recommended.
fluid surrounding the affected ligament. 13,55 The ane- Cold therapy in the form of an ice/water slurry applied
choic space between the ligament and the SDFT is often for 30 minutes twice a day during the acute inflammatory
reduced in size with desmitis of the oblique DSL. Chronic phase is beneficial. Pressure/support bandages can be
sonographic changes may include varying degrees of the applied in between the cold treatments and maintained
acute abnormalities within the ligament, hyperechoic for 2–3 weeks or as needed. NSAIDs can be administered
areas consistent with dense scar tissue formation, and for up to 2–3 weeks’ post‐injury. Feet and hoof‐pastern
dystrophic mineralization. 13,55 Periosteal proliferation in axis imbalances should be corrected if possible.
areas of ligament attachments may appear as irregular Once a definitive diagnosis has been made, a 6‐month
contours on the bone surface. Basilar sesamoid avulsion rest and rehabilitation program is currently recom-
fragments, desmitis of the ipsilateral branch of the sus- mended. 58,61 This usually involves a short period of stall
pensory ligament in the same limb, and fragments off confinement depending on the severity of the injury (3–6
the proximopalmar/plantar aspect of P1 may occur con- weeks), followed by increasing periods of hand‐walking
currently in more chronic cases. Ultrasonographic and controlled exercise. Hand‐walking exercise usually
identification of cruciate DSL injuries is difficult due to begins with 5 minutes once or twice a day, 3–5 days a
the location of these ligaments and therefore may be week, and then increases 4–5 minutes/week. Clinical
underdiagnosed. evaluation should be performed at 4–6 weeks, and if the
Ultrasonography of the palmar/plantar pastern horse has improved, controlled exercise can be increased.
region is difficult to perform and requires experience to If abnormalities were apparent on ultrasound, reeval-
become proficient. There are numerous soft tissue struc- uation is recommended 2–3 months post‐injury. Further
tures that must be ruled out as potential problems. controlled or free exercise recommendations are made
Therefore, only obvious abnormalities within the DSLs depending on the ultrasound findings. In one study of
may be recognized. In a recent study to describe the nor- 27 horses with DSL injuries, 76% of the horses success-
mal appearance of the DSLs using MRI, 80% of the fully resumed performance following a 6‐month con-
lesions found with MRI were not detected with ultra- trolled exercise program. 58
sonography. Although ultrasound can be useful to Adjunctive treatments that may be used in addition
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diagnose problems in the DSLs, lack of ultrasound to the rehabilitation protocol include extracorporeal
abnormalities does not rule out a problem within the shockwave, ligament splitting, injection of the DFTS