Joint Injections Compared Joint injections using corticosteroids, hyaluronic acid (HA) or a combination of the two are commonly used to treat synovitis and arthritis in performance horses. In this study, researchers compared the efficacy of one type of corticosteroid (triamcinolone acetate, TA) with and without HA for the treatment of lameness, localized to one limb only that responded to a diagnostic joint block. Eighty horses of various breeds were enrolled in the study with follow-up at 3 weeks by re-examining the horses and 3 months by an owner questionnaire. No other medications were permitted during the first 3 weeks of follow-up.

IV Tildren for Navicular Syndrome The efficacy of administering the injectable bisphosphonate medication for horses (Tildren) in two different ways was evaluated for the treatment of navicular syndrome. Twelve horses diagnosed with bilateral navicular syndrome were randomly assigned to receive Tildren either systemically by intravenous injection or by using regional limb perfusion, where the drug is “back-flushed” directly into the blood vessels of the lower limb so that it is delivered to the lower limb and hoof in a more direct, concentrated manner.

Researchers in Canada used cadaver limbs to study the effects of hoof angles and loading patterns on joint surface contact areas in the fetlock. Eight limbs from Standardbred horses that died for reasons unrelated to this study were fitted into a mechanical pendulum device to simulate hoof strike at a trot. Strips of pressure-sensitive film were placed across the joint surfaces inside the fetlock to measure contact areas, and the limb was loaded while simulating flat, toe-first and heel-first landings.

Veterinarians in Belgium examined the dorsopalmar and mediolateral hoof balance of five toed-in warmbloods that weren’t lame at the time of the study. They used a pressure plate to assess the symmetry of vertical ground reaction forces as a measure of hoof balance and limb loading symmetry at a walk. Their hypothesis was that toed-in conformation primarily affects mediolateral balance.

This investigation examined hoof tissues from horses affected by pituitary pars intermedia dysfunction (PPID or Cushing’s disease) with the hypothesis that pathologic changes consistent with laminitis would be found whether or not the animals showed clinical signs of laminitis. Tissues from 26 horses were examined including PPID affected horses with and without laminitis and controls. The length, width and appearance of primary and secondary epidermal lamellae were compared between the affected and the control horses.

An experimental study with 22 ponies was conducted to investigate the effects of feeding a diet high in nonstructural carbohydrates (starch) on the laminae of lean ponies compared with obese ponies. The ponies were sorted into lean (body condition ≤4) and obese (body condition ≥7) groups and half of each group was fed either a low starch hay diet or a high starch diet with added sweet feed and plant sugars. After 7 days, laminar tissue samples were collected and analyzed to measure the activity of naturally occurring substances that trigger inflammation (inflammatory mediators) and the expression of genes that control inflammation.

A 10-year study in the United Kingdom investigated the relationships between clinical signs, response to nerve blocks, X-ray and magnetic resonance imaging (MRI) findings for horses diagnosed with navicular disease. The 4,618 horses examined were presented with a complaint of forelimb lameness and received a typical clinical workup prior to MRI.

A study with dairy calves was conducted to determine if exercise in a mixed terrain (grass, dirt and rocks) affects development of the digital cushion and pedal bones compared to less exercise in a grassy environment. Two-month-old animals were randomly placed into exercise and control groups. For 4 months, the exercise group was fed and watered at opposite ends of a half-mile long lane. Feeding was twice a day so the animals ran or walked briskly behind a feed truck 1 mile a day and walked leisurely to return to water 1 mile a day. After 4 months, the volume and surface areas of the digital cushion and the volumes of the short pastern and coffin bones were compared using magnetic resonance imaging and computed tomography.

Researchers in Vienna examined the utility of using heart rate and heart rate variability to estimate the degree of pain felt by 12 horses with clinically obvious laminitis compared to five unaffected control horses. In addition, heart rates were compared to the Obel pain scale, historically used to describe the severity of laminitis pain where “1” is used for horses that shift their weight from one foot to another while standing or are lame only at a trot and “4” is used for horses that are very reluctant or refuse to move.