Page 762 - Adams and Stashak's Lameness in Horses, 7th Edition

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B

A

C

Figure 5.129. Radiograph (A), ultrasound (B), and intraoperative strated by a defect in the subchondral bone on the ultrasonographic
(C) images demonstrating an SCL that involved a large percentage images (B). Thickening of the articular cartilage can be seen
of the articular surface. Note the joint space narrowing on the arthroscopically (C).
radiographic image (A) and the presence of the SCL as demon-

pen, and radiographs reevaluated every 4–6 weeks. If no of the debrided cyst with various products, and trans-
change is present or if the cyst is enlarging, then surgical cystic screw placement.
options should be considered. However, there are some Debridement of cystic contents has been shown to be
horses of various ages that respond well to intra‐articu- effective in 56%–77% of cases that undergo surgery. In
lar and systemic medications and in some instances may these cases, the joint is arthroscopically explored, and
be maintained for competition. Cases that respond to the contents of the cyst are removed. It is important to
medical management have SCLs that are either small, remove the lining of the SCL because it contains inflam-
have a small articular component, or may show limited matory mediators. Some have advocated drilling of the
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communication between the cyst and the joint surface. subchondral bone to facilitate access of blood supply to
The latter may demonstrate an intact subchondral bone the cyst; however, Howard et al. showed that in some of
plate. It is unknown whether the SCL is relatively stable these cases, the drill holes lead to enlargement of the
in these cases, leading to adequate support of the articu- lesions. Nevertheless, some advocate using microfrac-
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lar surface. Rest has also been reported to be successful ture on the cyst wall, especially when sclerosis is present.
in treating some cases of SCL in the tibia . These horses are typically rested 6–12 months after
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Surgery is a common therapy for SCLs because horses surgery.
that suffer lameness from this problem can rarely per- The prognosis generally is good for these lesions.
form with the existence of the cyst. Several methods of Lewis has shown that 72% of horses had returned to
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surgical treatment have been used with varying degrees intended use, although 14 of the 67 horses studied had
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of success, including debridement of the cyst contents, occasional lameness that was managed medically.
injection of the cystic lining with corticosteroids, grafting Howard et al. showed that although 74% were successful,