Arravale18 - Nothing Keeps Him Down!
ArravaleAugust 6th, 2018
Below is an article Chelsey has shared with us that helps explain Arravale18's procedure.
Angular Limb Deformities in Young Horses
By Kentucky Equine Research Staff
When one or more of a foal’s limbs has the appearance of being bent sideways or rotated, the condition is known as an angular limb deformity. A number of foals exhibit this problem, which sometimes self-corrects in mild cases as the foal grows. More significant deformities can be treated during the foal’s early months of life, leading to a resolution of the deformity and a better chance for an athletic future when the horse matures.
Angular limb deformities can take the form of a lateral or medial deviation of the limb. The angulation can arise in association with uneven elongation from the growth plate (physis) or alternatively can be involved in abnormalities of the cuboidal bones of the carpus and tarsus. Most commonly the problems are associated with uneven physeal growth and involve the physes of the distal radius, metacarpus and metatarsus, or tibia, in that order. When a deviation results in the lower part of the limb bending out (lateral), it is termed valgus, while a deviation to the inside (medial) is termed varus. The total nomenclature for angular deformities is derived by combining the name of the involved joint or the joint immediately distal to the affected growth plate and the type of deviation. For example, a lateral deviation of the distal limb due to an affected distal radial growth plate or abnormal cuboidal bones of the carpus would be termed carpal valgus.
The etiology of angular limb deformities is complex and thought to be multifactorial. The two main categories of factors include perinatal and developmental. Perinatal factors are usually involved when a foal is born with an angular limb deformity, whereas foals that are normal at birth but develop an angular limb deformity are more likely to suffer from one or more of the developmental factors.
Some degree of carpal valgus is thought to be a normal deformity in the young foal, and most of these correct naturally. There have been no nutritional factors consistently associated with this disease. In managing these cases, one must first realize that depending on the location there is a typical growth curve for each of the physes. In the carpus, the growth plate stays open for two years and there is a diminishing rate of lengthening that continues for over a year. On the other hand, when the deformity involves the fetlock, the time available for manipulation of the growth curve is much lower. All effective elongation in the physis at the distal metacarpus or metatarsus ceases around three months of age.
When an angular limb deformity involves the bones in the joint, such as the carpus or tarsus, this needs to be recognized radiographically and is treated with braces or casts to maintain the limb in alignment while the cuboidal bones ossify. This problem occurs relatively infrequently. When it does, it is often associated with a premature foal or a hypothyroid foal.
The more common situation of growth imbalance is associated with the physis, and management depends on the location. In the fetlock, it is generally considered an emergency and periosteal stripping is done at one to two months. The ideal time is one month and it should be done by two months. At three months, the amount of correction that can be attained is much lower and the blemish following periosteal elevation is more obvious. With carpal valgus, there is much more time for manipulation, and periosteal strippings between two and six months are quite common. The principle of periosteal stripping is to transect the periosteum (which acts as a normal restraining device to physeal lengthening on that side) and allow a speeding up of cartilage growth in the physis (hence, lengthening) on that side. It is generally a simple, complication-free procedure. If the problem is not diagnosed until it is too late to obtain sufficient benefit from periosteal stripping, a more drastic option is stapling or screw and wire fixation of the physis. The principle here is to halt growth on the fastest growing side to allow continued growth on the opposite side of the physis and straightening of the limb.
It is important to consult with your veterinarian regarding the best treatment and management options for foals with angular limb deformities. All foals cannot be considered the same in regard to conservative or surgical treatment. Breed differences, age of the foal, and location and severity of the angular limb deformity all impact the decision for the best therapy.