Equine Orthopaedics and Rheumatology Q&A 07

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An eight-year-old Thoroughbred gelding presented with a right forelimb lameness, grade 2/5 at the trot, of eight weeks duration. The lameness was insidious in onset, did not improve with rest or exercise, and was the same on any surface.

Question	Answer		Article
What abnormal features of the right forelimb can be recognised in the image?	There is marked distension of the digital sheath on the palmar aspect of the fetlock. The distal end of the swelling has a notched appearance. The horse has a slightly broken back hoof–pastern axis and low heels.		Link to Article
From the history and clinical signs, what causes of lameness would you consider?	Annular ligament syndrome is the most obvious possibility. Superficial or deep digital flexor tendon injuries. Previous penetrating wounds into the sheath, may be contributing factors. But in view of the poor foot conformation, a foot problem should also be considered as the cause of the lameness, since these digital sheath swellings are not always painful.		Link to Article
What further tests would you perform to confirm your diagnosis?	Intrasynovial analgesia of the digital sheath will not always abolish the lameness, presumably because of adhesions or the mechanical influence of the constricted annular ligament. Analgesia of the palmar nerves proximal to the fetlock is usually effective. Ultrasonography is important for evaluation of the annular ligament and the flexor tendons, and may indicate the presence of adhesions. Regional analgesia of the foot should be performed to ensure that foot pain is not involved.		Link to Article
How would you treat this case?	Acute cases should be treated with rest, possibly combined with both topical and systemic anti-inflammatory drug therapy. If this fails, an annular ligament desmotomy is indicated.		Link to Article