Common Lameness in the Cutting and Reining Horse
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Reprinted in the IVIS website with the permission of AAEP Close window to return to IVIS IN DEPTH: LAMENESS IN THE WESTERN PERFORMANCE HORSE Common Lameness in the Cutting and Reining Horse Bradley R. Jackman, DVM, MS, Diplomate ACVS Author’s address: Pioneer Equine Hospital, Inc., 11501 Pioneer Avenue, Oakdale, CA 95361. © 2001 AAEP. 1. Introduction 2. Forelimb Lameness The cutting and reining horse industry is growing Forelimb lameness problems can be grouped into rapidly, with enthusiasts ranging from the absentee two different types: concussion and fatigue. To horse owner to the full-time professional. Owners achieve the athletic ability needed to be competitive can be involved in small local weekend shows or in today’s industry, breeding programs for these national events with over one million dollars in prize horses are very regimented and follow successful money. As this industry has grown, so has the bloodlines. This has enabled the horses to become competitive nature of the owners and the ability of extremely agile and quick, but other characteristics, the horses. such as small stature and small foot size, have also been inherited. Lameness from concussion is re- Cutting and reining horses are primarily Quarter lated to the small feet of these horses as well as to Horses and Paints. These horses are bred with an the work required. Fatigue plays a role because emphasis on small stature (14–15 hands), agility, these horses are required to be calm and completely and the mental capacity to perform under pressure. in control when performing. Therefore, they often During individual events, the horses have to be un- need to be galloped for extended periods of time der complete control while performing quick stops prior to entering the show ring. and high-torque turns (Figs. 1 and 2). Additionally, most of these horses begin training as late yearlings 3. Palmar Heel Pain/Navicular Syndrome and early two-year-olds, with the goal that they will As mentioned, cutting and reining horses experience compete in fall and winter competitions as three- extensive and prolonged training at a young age and year-olds. This small stature, agility, and athletic often exhibit lameness, which can be alleviated with use predispose to certain stresses and injuries. analgesia of the palmar digital nerves. Analgesia Due to the increasing popularity and nationwide of the distal interphalangeal joint is often useful in growth of the cutting and reining industry, it is further localizing the lameness; it has been sug- imperative for equine practitioners to become famil- gested, however, that the specificity of this block is iar with the diagnosis and treatment options of in- questionable and that it can desensitize the sole juries common to these horses. when large volumes of anesthetic are used.1 NOTES 6 2001 ր Vol. 47 ր AAEP PROCEEDINGS Proceedings of the Annual Convention of the AAEP 2001 Reprinted in the IVIS website with the permission of AAEP Close window to return to IVIS IN DEPTH: LAMENESS IN THE WESTERN PERFORMANCE HORSE Fig. 1. Reining horses must perform and excel at high-speed stops. Fig. 2. Quick high-torque turns are necessary in cutting horses. AAEP PROCEEDINGS ր Vol. 47 ր 2001 7 Proceedings of the Annual Convention of the AAEP 2001 Reprinted in the IVIS website with the permission of AAEP Close window to return to IVIS IN DEPTH: LAMENESS IN THE WESTERN PERFORMANCE HORSE After the lameness has been localized, radio- ament, an ultrasonographic examination of the lig- graphs are made of the foot. The radiographs are ament is necessary. Fiber pattern, ligament size, carefully examined for abnormalities as well as for and percentage of damaged tissue should be as- imbalance and angular deformities of the foot. Ero- sessed. Additionally, an ultrasound of the opposite sion of the flexor cortex, cystic-type lesions, and limb should be taken as a comparison. Ultrasono- medullary sclerosis of the navicular bone are more graphic findings do not always coincide with the severe lesions that may warrant a lesser progno- degree of lameness. Some horses have less echo- sis. If significant radiographic abnormalities exist, genic areas in the proximal dorsal suspensory liga- a diagnosis of navicular syndrome is made. ment that are normal and can be determined only by The cornerstone of initial therapy is appropriate contralateral limb ultrasound examination. consistent shoeing. It is imperative that the foot be The treatment for suspensory ligament desmitis is balanced and at an angle appropriate for the horse. rest, corrective shoeing, systemic nonsteroidal anti- Effort must be made to hasten breakover by short- inflammatory medications, and, occasionally, local ening and rolling the toe and providing adequate injection of the proximal suspensory lesion. The heel support. The interval between shoeings is duration of rest is determined by the severity of usually 5–6 weeks maximum. Additionally, oral ultrasonographic abnormalities, degree of lameness, medications such as isoxsuprine hydrochloride and and subsequent ultrasound examinations, which aspirin are used to enhance blood flow to the foot. monitor healing. In most cases, an initial 60 days If the lameness is severe and/or there is evidence of of stall rest is recommended, with prescribed hand coffin joint inflammation, intra-articular injection of walking beginning 2 weeks after examination. The the distal interphalangeal joint with hyaluronic acid amount of hand walking is slowly increased while and a corticosteroid (e.g., 6 mg triamcinolone) is the horse is confined to a stall. At 60 days, the performed. In more severe or nonresponsive cases, horse is reexamined and an ultrasound is made. palmar digital neurectomy may be required to main- Further rest and exercise regimens are recom- tain athletic function. mended at that time. Corrective shoeing involves 4. Suspensory Ligament Desmitis keeping the toes short, maintaining an appropriate angle, and, usually, the application of an egg bar Inflammation and injury of the suspensory ligament shoe to facilitate fetlock support. In situations is a common source of forelimb lameness in the where lameness is not severe and there are no ul- cutting and reining horse. Severity can vary from trasonographic abnormalities, local injection of the mild pain on palpation to acute and relatively severe proximal suspensory lesion may be performed. lameness. Because these horses must have a quiet Most often, a corticosteroid is used in conjunction and calm demeanor while performing, most of them with polysulfated glycosaminoglycan.a Occasion- have to be galloped prior to performing at their most b demanding level. In addition to fatigue, other pre- ally, Sarapin is added as well. In cases where the disposing factors are improper shoeing (long toes, lameness and lesion are severe or where there is a uneven feet, improper angles, lack of heel support), slow or poor response to conventional therapy, bone hind limb soreness, and poor ground conditions. marrow aspirated from the sternum is often injected in the affected proximal suspensory ligament of Injuries to the suspensory ligament usually occur 2 at its proximal origin and, to a lesser degree, at these horses. its distal branches. Proximal suspensory desmitis Frequently in cutting and reining horses, there is is a common cause of lameness in cutting and rein- palpable pain in the proximal suspensory region and ing horses. These horses usually exhibit lameness a slightly shortened gait but no definitive lameness. that is 1 or 2 grades more severe when they are These horses are probably suffering from hock sore- circled with the affected limb on the outside of the ness caused by using their front ends more exten- circle (e.g., counterclockwise with right forelimb sively than normal. The suspensory desmitis in lameness). Sequential injections of local anesthe- these horses usually does not require direct treat- sia are used to localize the lameness to the affected ment and the problem can be alleviated with correc- region. The proximal suspensory region can be de- tion of the hock soreness. sensitized with local infusion of anesthetic around The prognosis with suspensory desmitis is favor- the suspensory ligament or by perineural anesthetic able and generally predictable. However, a horse injection around the lateral palmar nerve at the with moderate to severe lesions is more predisposed level of the middle carpal joint just distal to the to recurring injury. Several steps can be taken to accessory carpal bone. If local infiltration is used, prevent further injury after healing has occurred. ultrasound examination is often postponed for one Proper conditioning is necessary to reduce the risk day to minimize possible distortion from the local of fatigue. Appropriate shoeing is necessary to anesthetic injection. avoid long toes and improper angles. We often After the lameness has been localized, the affected keep these horses in egg bar shoes for their entire region is radiographed to determine if proximal athletic careers. Potentially the most important metacarpal or fetlock abnormalities are present. To preventative measure is to keep the horses as com- characterize the damage within the suspensory lig- fortable as possible and to keep them working off 8 2001 ր Vol. 47 ր AAEP PROCEEDINGS Proceedings of the Annual Convention of the AAEP 2001 Reprinted in the IVIS website with the permission of AAEP Close window to return to IVIS IN DEPTH: LAMENESS IN THE WESTERN PERFORMANCE HORSE Fig. 3. The hindlimbs in cutting and reining horses undergo frequent and excessive stress when training and performing. their hind ends to prevent excessive strain on the municate in only 7–38% of horses; the distal tarsal front limbs. joints very rarely communicate with the proximal intertarsal or tibiotarsal joints.3–5 The distal tar- 5. Hindlimb Lameness sal joints are low-motion joints that sustain repeti- Cutting and reining horses place a great deal of tive torque force in these horses.