Fact Sheet Sponsored by: Lameness in Horses Prompt recognition and treatment of lameness is imperative to minimize losses Overview flexion tests (bending individual joints for Lameness, traditionally defined as any an extented amout of time and then watch- abnormal gait, is a common event in the ing the horse trot off) to determine which equine industry, contributing to untold areas are painful, and if a decreased range economic and horse losses annually.1,2 To- of motion exists. day, veterinarians also accept that even be- In the United States veterinarians typi- havior changes, not just gait changes, can cally classify the degree of lameness by cause lameness in horses due to pain in the grade using the American Association of neck, withers, shoulders, back, loin, hips, Equine Practitioner’s (AAEP) lameness legs, or feet.2 grading system:2 Grade 0 is defined as no detectable lame- Causes of Lameness ness under any circumstances. A number of conditions can result in Grade 1 is defined as lameness that is diffi- lameness. These include trauma, congeni- cult to observe and is inconsistently appar- tal conditions (e.g., contracted tendons), ent regardless of the circumstances (e.g., acquired abnormalities (e.g., osteochon- in hand or under saddle, hard surface, in- dritis dissecans), and infection (e.g., septic/ cline, or circling). infectious arthritis). Essentially, any body Grade 2 lameness is difficult to detect at a ON part that has nerve endings can serve as a S walk or trot in a straight line, but is consis- source of pain, and horses with poor confor- A LAR tently apparent under particular circum- IC mation are more likely to suffer problems ER stances (e.g., under saddle, hard surface, with tendons, ligaments, and joints than During a lameness examination, a veterinarian incline). watches the horse walk and trot in a straight line 1 horses with more ideal conformation. to see how the horse’s limbs travel in motion. Grade 3 lameness is consistently observed Even factors unrelated to the musculo- at a trot in all circumstances. skeletal system, such as metabolic, circu- 80% of the time the culprits are the hock Grade 4 lameness is obvious with a marked latory, and nervous system abnormalities and/or stifle. head nod, hip hike, and/or shortened (e.g., wobbler syndrome/cervical stenotic Most veterinarians use a step-by-step stride. myelopathy) can cause lameness. approach to lameness and begin with a Grade 5 lameness is obvious with minimal complete lameness history of the horse, a weight bearing either during motion or at Diagnosing Lameness general physical examination, and confor- rest. The horse might be unable to move. Lameness due to musculoskeletal ab- mation assessment. The “standing” part of This grading system helps veterinarians normalities is the leading cause of poor the exam also involves feeling the horse’s describe lameness consistently (especially performance in athletic horses.4 Your vet- body for heat and swelling. He or she pal- when communicating with other veterinar- erinarian must have a detailed knowledge pates individual tendons and ligaments ians) and track the lameness in the same of horse anatomy, mechanics, conforma- and assess blood flow to the feet. Hoof tes- horse over time. It is important to rec- tion, and breed characteristics to evaluate ters are used if foot pain is suspected. ognize that this system is subjective and a lameness quickly and accurately. Next, the veterinarian will evaluate the therefore imperfect. Not surprisingly, diagnosing lameness is way the horse moves in hand and/or under One recent study identified a lack of re- sometimes challenging for even the most saddle. A variety of surfaces can be used. A liability and repeatability even in experi- experienced veterinarian. Over the years, hard, level surface might be used in some enced veterinarians’ lameness evaluations. veterinarians have devised a list of general cases, but others might mandate the use of As a result, the research group challenged rules and patterns when evaluating a lame a deep, sand ring. During this part of the the equine industry to search for and devel- horse. For example, most lameness oc- exam, the veterinarian can establish which op “a more objective and reliable method curs in the forelimb, and at least 95% of limb(s) is/are involved. of lameness evaluation for use in the field” forelimb lameness occurs from the knee Once the affected limb(s) is/are identi- and noted that such efforts “should be en- down.3 When the hind limb is involved, fied, the veterinarian will likely perform couraged and supported.”5 This Fact Sheet may be reprinted and distributed in this exact form for educational purposes only in print or electronically. It may not be used for commercial purposes in print or electronically or republished on a website, forum, or blog. For more horse health information on this and other topics visit TheHorse.com. Published by The Horse: Your Guide To Equine Health Care, © Copyright 2012 Blood-Horse Publications. Contact [email protected]. Fact Sheet A veterinarian can also use regional an- unilateral or bilateral lameness exists; and compounds,7 physical therapy,8 extracor- esthesia to temporarily block the joints and if the horse needs to be worked in his nat- poreal shock wave therapy (ESWT), IRAP nerves from sensing pain as a way to iden- ural setting (e.g., under saddle for a dres- (interleukin-1 receptor antagonist protein), tify the pain source. For example, blocking sage horse).6 platelet-rich plasma (PRP), and/or stem cell the palmar digital nerves that supply the Once your veterinarian has isolated the therapy. Information on each of these ther- foot can (generally) desensitize the heel source of your horse’s lameness, he/she will apies is available on TheHorse.com. h and sole region to help localize the pain frequently perform radiographs (X rays). to the rear of the foot, which is caused by Ultrasonography is also quite common for KEY REFERENCES conditions such as navicular disease. tendon and ligament injuries, among oth- 1. Thal D. Understanding lameness. www.aaep.org/ Once a specific nerve or joint has been ers. Advanced imaging techniques such health_articles_view.php?id=296 “blocked,” your veterinarian will re- as a bone scan (nuclear scintigraphy), 2. Bayer HealthCare Animal Brochure. Lameness. www. aaep.org/health_articles_view.php?id=280 evaluate your horse to determine if the magnetic resonance imaging (MRI), and 3. Stashak TS. Examination for lameness. Stashak TS, lameness has improved and, if so, to what computed tomography (CT) might also be ed. Adams’ lameness in horses. 5th ed. Philadelphia (PA); extent. If a horse was a grade 3 before needed.1 Lippincott Williams & Wilkins, 2002. 4. Moore RM, Burba DJ. Musculoskeletal causes of lame- blocking and a grade 1 or 0 after blocking, ness and poor performance in horses. www.equine.vetmed. then the blocked area likely contributes to Treatment and Prognosis lsu.edu/lameness%20evaluation.pdf the lameness. Treatment and prognosis for any lame- 5. Oke S. Vets seek reliable approach to lameness It is important to note that athletic hors- ness will vary dramatically depending on exams. www.TheHorse.com/15503 6. Dyson S. How to: recognize a subtle lameness. es are often lame in more than one limb or the use of the horse and the exact nature of Proceeding of the 50th British Equine Veterinary Association have secondary, compensatory lameness. the lameness. Your horse’s treatment plan Congress. 2011. www.ivis.org/proceedings/beva/2011/43. Alternatively, if no improvement in lame- could involve conservative therapy (e.g., pdf 7. Epsy B, Harper J. Lameness & joint medications. ness grade is noted after a block, then the stall rest, hand walking) or surgery (e.g., 2011. www.aaep.org/siteadmin/modules/page_editor/ source of pain likely resides in different to remove chip fractures or repair a frac- images/files/OSTEOARTHRITIS.doc anatomic location. ture of a long bone with plates or screws). 8. Oke S. The science behind rehabilitation therapy. www. thehorse.com/ViewArticle.aspx?ID=19406 Localizing lameness can be time- Other treatment options, depending on the consuming and dependent on the horse’s cause of lameness, could include nonsteroi- Authored by Stacey Oke, DVM, MSc; temperament; natural gait; whether it is dal anti-inflammatory drugs (NSAIDs), reviewed by R. Stuart Shoemaker, DVM, the hind or forelimb that is involved; if a joint injection with various anti-arthritic Dipl. ACVS.