b'SPORTS MEDICINEPost-treatment, he recommends rehab- Theyre not wantingat the lower hock joints, as well as a pain bing horses with a controlled exerciseresponse to palpation.program that might include traditionalto get down and followWhen the limb is flexed for the hock, in-hand, ponied, and under-tack exer- the calf, or theyre notthe lameness will become apparent or be cises, as well as treadmill work and waterexacerbated, he says, and there may be exercise. He also recommends seekinggetting into the grounddecreased range of motion of the hock HBOT, if available. when theyre stopping ifjoint.PrognosisWhile it depends on theHow its diagnosedOften, a lameness injurys cause and severity, affected horsestheyre a reiner.Thoseexam (including longeing), flexion tests, generally have a fair chance to return toare indicators thatnerve and joint blocks, and radiography soundness, Bell said. are sufficient to diagnose OA. In some somethings going on. cases veterinarians might use more ad-Hock Osteoarthritis DR. VERNON DRYDEN vanced imaging, including CT, MRI, bone Commonly affected joints in Westernscans, and PET scans, says Bell.performance disciplines include the lowerHow its treatedAt its simplest, treat-(distal) hocks, pasterns (in a conditionfollow the calf, or theyre not gettingment consists of anti-inflammatory drugs also known as ringbone), and stifles; here,into the ground when theyre stoppingand a reduced exercise program for a well focus on osteoarthritis (OA) in theif theyre a reiner, or theyre not want- time. If that isnt effective, joint injections hocks, which is a frequent problem in alling to stop with the calf on a tie-off,are a frequent next step.disciplines. Dryden says. All those are indicators thatTypically, Ill treat these with a steroid Our sources say many horses withsomethings going onthey dont have toand hyaluronic acid (HA), Dryden says. distal hock OA exhibit poor performancebe overtly lame. DepoMedrol (methylprednisolone, a and/or a shortened or stabby gait. Bell adds that there might be heat and/ corticosteroid) and Hyvisc (HA) is what I Theyre not wanting to get down andor bony swellings on the inside of the legtypically use.Bell adds, Steroids typically take around 10 to 14 days to have effect and usually last for six to nine monthsalleviating lameness symptoms.He says veterinarians also use IRAP and PRP injections, as well as shock wave therapy, to combat distal hock OA.Our sources agree that joint fusion might be the best bet for managing severe distal hock OA cases.Fusion of the joint results in relief of pain from arthritis with a small loss in torque transfer motion in the lower hock, Bell says.Surgical fusion is also an option. How-ever, surgery poses its own limitations, including cost and anethesia risks, and in recent years veterinarians have instead explored using ethyl alcohol to hasten the fusing process, called ankylosis.Veterinarians can inject alcoholsterilely and very technicallyinto the joint spaces of the distal hock joints, which denatures the cartilage (alters its properties) and allows them to fuse, Dryden says. Bell says fusion occurs over four to six months after surgery or four to 12 months following alcohol injection.Once they fuse and theres no more movement in those joints, theyre sound, Dryden adds.PrognosisWith careful management, many horses with hock OA have a good 42August 2019The Horse | TheHorse.com'