46TH
ANNUAL
CONGRESS
OF
THE
SAEVA
SKUKUZA
16-‐20
FEBRUARY
2014
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lameness. It is widely agreed that radiographic evidence of osteoarthritis is
considered a poor prognostic indicator. I prefer to ultrasound lame horses to assess
any possible meniscal damage prior to recommending intralesional steroids. If there
is evidence of osteoarthritis or meniscal damage, arthroscopic guided in jection is
preferred to assess the joint, debride cartilage as necessary and get more prognostic
information.
There are a number of treatment options described for this condition. These
include prolonged rest (12-18 months) progressing from box confinement to
paddock. Intra-articular medications (hyaluronic acid and corticosteroids) are often
used concurrently with rest. Biphosphonates (Tildren®) may also be of benefit
however long term follow up data following Tildren® administration is not yet
available. Arthroscopic curettage (with or without microfracture techniques or
forage) was originally described as the treatment of choice.11-14 More recently stem
cells and PRP injections into the debrided cyst have been described, as well as
grafting techniques.15 A long convalescence following arthroscopic curettage is
anticipated, and successful resolution of the lameness is reported between 64-74%.
11,13
In recent years alternative treatment options have been explored, including
intralesional injection of corticosteroids under arthroscopic or ultrasonographic
guidance.16-19 This less invasive technique has been associated with a shorter
convalescent time and similar results in young horses. The rationale behind
intralesional steroids is that injection into the lining will combat the destructive
mediators that the lining produces, resulting in a reduction in inflammation, a halt in
cyst progression and hopefully subsequent healing of the SCL.
Ultrasound guided intralesional injection of triamcinolone acetonide is currently the
treatment most commonly employed at Agnes Banks Equine Clinic. All owners are
offered arthroscopic guided injection, however usually elect for the simpler, less
invasive and less expensive ultrasound guided technique. Under general anaesthesia
and in dorsal recumbency, the stifle is placed in approximately 90 degree flexed
position. After clipping a 12-15 MHz linear probe is used to identify the SCL in the
medial femoral condyle. The leg flexion is adjusted as necessary and the leg fixed in
position, the probe position is marked (away from the injection site) and a surgical
prep performed. Under ultrasound guidance an 18ga 5cm spinal needle is directed
into the SCL until it contacts bone. Twenty mg triamcinolone acetonide is then
injected. The needle is redirected as soon as any leakage into the joint is apparent,
or after approximately 1/3 of the volume is injected. The needle is repositioned into
a different are of the SCL approximately 3 times to try to target a wider area of the
cyst lining. As the needle is withdrawn from the SCL, 20 mg hyaluronic acid and 200
mg gentamicin is injected into the medial femorotibial joint. The horse is treated
with perioperative procaine penicillin (22 mg/kg IM) and phenylbutazone (4.4 mg.kg
IV or PO). If the horse is lame at a walk prior to injection, phenylbutazone is
continued for 1-2 weeks (usually at 2.2 mg/kg PO SID) and it is recommended the
horse is confined to a box or small yard until sound at a walk. Recheck radiographs
are performed 3-4 month post injection. A total of 6 months out of training is
anticipated, but varies from case to case.
This technique is likely most suited to young horses, preferably with no or mild
lameness, and without any radiographic evidence of osteoarthritis.
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