Article #4 CE Angular Limb Deformities in Foals: Treatment and Prognosis* Nicolai Jansson, DVM, PhD, DECVS Skara Equine Hospital Skara, Sweden Norm G. Ducharme, DVM, MSc, DACVS Cornell University ABSTRACT: This article presents an overview of the clinical management of foals with angular limb deformities. Both conservative and surgical treatment options exist; the choice of which to use should be based on the type, severity, and location of the deformity as well as the age of the foal. Conservative measures include controlled exercise, rigid external limb support, and corrective hoof trimming. Surgical treatment modalities comprise tech- niques for manipulating physeal growth and, after physeal closure, various corrective osteotomy or ostectomy methods. The prognosis is generally good if treatment is initi- ated well in advance of physeal closure. ngular limb deformities and their treat- Conservative Treatment ment in foals and young horses constitute In most foals born with mild to moderate a significant part of the orthopedic prob- angular deformities, spontaneous resolution A 2 lems that veterinarians must manage. This article occurs within the first 2 to 4 weeks of life. In discusses the clinical management and prognosis newborn foals, periarticular laxity is the most of these postural deformities. likely cause, and these foals require no special treatment other than a short period of con- TREATMENT trolled exercise. In our opinion, mildly and The absence of controlled studies has moderately affected foals should not be confined impaired the accumulation of scientific data to a stall because exercise is important for nor- guiding the management of angular limb defor- mal muscular development and resolution of the mities in foals (Table 1). The following man- angular deformity. The opposite treatment (i.e., agement recommendations are based on the unlimited exercise) often leads to fatigue, which literature and our experience in treating foals exacerbates the deformity. Therefore, we suggest with angular limb deformities. Also, we use the that the mare and foal be placed in a small pad- terms mild, moderate, and severe angular defor- dock (e.g., 15 × 15 m). Alternatively, the mare mities, which are defined as less than 10˚, 10˚ to and foal may be kept in a large stall (e.g., 5 × 3 20˚, and greater than 20˚, m) and allowed frequent access to a small pad- Send comments/questions via email respectively.1 dock for a few hours at a time to prevent exces- [email protected], *A companion article on cause sive fatigue. There is a lack of scientific data fax 800-556-3288, or web and diagnosis appeared in the documenting how much confinement these CompendiumVet.com January 2005 issue (p. 48). foals need, and these recommendations are COMPENDIUM 134 February 2005 Angular Limb Deformities in Foals:Treatment and Prognosis CE 135 Table 1. Treatment Modalities for Foals with Angular Limb Deformities Treatment Modality Angular Limb Deformity Stall and/or small paddock rest All types Rigid external support to the limb (e.g., splint Periarticular laxity bandage or tube cast) Cuboidal bone hypoplasia Hypoplasia of the proximal aspect of the fourth metacarpal bone Corrective hoof measures (e.g., trimming, Deformities originating in a long bone before cessation of physeal shoeing) growth Surgical manipulation of physeal growth (growth Deformities originating in a long bone before cessation of physeal acceleration and/or growth retardation techniques) growth Corrective ostectomy or osteotomy Deformities originating in a long bone after cessation of physeal growth based only on our experience. that is bent to follow the dorsal contour of the limb.2 Foals with severe periarticular laxity and grave angular For splint bandaging, the foal should be sedated and lat- deformities are unlikely to experience spontaneous cor- erally recumbent. After this, the deformity can be man- rection.2 These foals often need some form of external ually corrected and the splint applied to the limb.a support to straighten the limb in addition to stall and Splint bandages should be changed at least every 3 to 4 small paddock rest. A splint bandage or tube cast (i.e., a days to check for skin pressure sores.3 However, a cast that does not enclose the foot and fetlock) can be shorter bandage change interval is preferred. applied to keep the limb straight and allow the periar- In our experience, managing splint bandages is prob- ticular tissues and collateral ligaments to strengthen lematic on many farms because of the help necessary in within 2 to 4 weeks.2–4 By not incorporating the foot, a placing a splint: someone to hold the mare, someone to splint bandage or tube cast allows weightbearing, thus restrain the foal, and someone to apply the splint. The preventing muscular atrophy and worsening of the con- labor required for splint application competes with the Confinement to reduce axial compressive forces on the affected limb is an important part of managing angular limb deformities in foals. dition. However, treatment of periarticular laxity by demands of a breeding farm during the breeding season. rigid external support has been debated and, according To minimize these labor concerns, we have used snap-on to one author, may actually delay strengthening of the splints or tube casting. The snap-on splint is custom- periarticular structures.5 Because periarticular laxity made from padded fiberglass (Endurasplint 2, Carapace most often affects the carpus or tarsus, the splint band- Inc., New Tazewell, TN; Figure 1). These splints have age or cast should extend from the proximal radius or enough strength for foals younger than 6 weeks of age. tibia to just above the fetlock joint. We use a transected The foal should be sedated and laterally recumbent. A polyvinylchloride pipe to create a hemispherical splint rectal sleeve should be placed over the limb to be that can be applied to the palmar aspect of the forelimb splinted to protect it from contact with water and over roll cotton padding regardless of whether a valgus polyurethane resin. The splint should be immersed in or varus deformity is being treated. water at a temperature of 69.8˚F to 73.4˚F (21˚C to Because of the anatomy of the hindlimb, tarsal defor- aAuer JA: Personal communication, University of Zurich, mities can be best stabilized by applying a dorsal splint Switzerland, 2003. February 2005 COMPENDIUM 136 CE Angular Limb Deformities in Foals:Treatment and Prognosis Figure 2. Radiograph of the right carpus of a 1-day-old mixed-breed foal with carpal valgus caused by carpal bone hypoplasia. Figure 1. Endurasplint (Carapace Inc., New Tazewell, TN) is made of padded fiberglass and has the advantage of being molded to follow the contour of the limb, thereby reducing the risk of skin pressure sores. Note the rounded and The foal was treated with incompletely ossified carpal external support to the limb, bones as well as the which allowed the carpal bones 23˚C), and excess water should subsequently be squeezed hypoplastic proximal aspect of and the proximal aspect of the the fourth metacarpal bone fourth metacarpal bone to out. The splint should be applied to the limb so that the contributing to the valgus ossify under even loading as felt is against the skin and half of the circumference of deformity. seen on this radiograph taken the limb is covered. It should then be secured to the limb 3 weeks later. (Courtesy of Dr. with gauze and allowed to dry sufficiently to hold its Tony Pease, Cornell University, shape. The splint should be removed and allowed to set Ithaca, NY) for 5 to 7 minutes before reapplying it to the limb. Because the splint is padded and molded to the contour of the limb, it should be easy to place and only a single shells immediately following application.7 The shells may roll of self-adhesive elastic bandage should be needed to then be removed every 3 to 4 days to evaluate the skin.8 secure it, making it convenient for daily use. In a hospital It should be noted that foals cope with rigid uni- or setting, we recommend leaving the splint on for 12 hours bilateral forelimb bandages or unilateral hindlimb band- at a time to prevent pressure sores; the splint should be ages without difficulty, whereas they need help rising if applied at night while the foal is less active. both hindlimbs require rigid external support.4 Another means of establishing external support to a In foals born with angular deformities associated with limb is application of a tube cast, which is best done with cuboidal bone hypoplasia of the carpus and/or tarsus, the patient under general anesthesia.4,6 Casts should be treatment should be directed toward maintaining normal changed at 10- to 14-day intervals to allow rapid growth alignment of the affected limb and allowing the carti- of young foals.6,7 The main disadvantage of tube casting laginous templates to ossify under even loading4–6,8,9 (Fig- is the risk of developing skin pressure necrosis; this can ure 2). Except for very mild cases (<7˚), untreated foals be somewhat reduced by cutting the cast into two half are at risk of developing permanent angular limb defor- COMPENDIUM February 2005 Angular Limb Deformities in Foals:Treatment and Prognosis CE 137 Orthotics We have treated a select number of weanlings with angular deformities using orthotic devices (orthoses). Orthotics is the science that focuses on the design, manufacturing, application, and evaluation of orthotic devices to assist in patient ambulation and correction of various skeletal deformities. Using orthotic devices in children is well established and recommended for a variety of pediatric conditions.a–c In veterinary medicine, the use of orthotic devices has been extremely limited (excluding corrective shoeing and the standard splints and casts described in this article).