ANGULAR LIMB DEFORMITIES IN HORSES

Angular limb deformities (ALDs) are often observed in young and growin g horses. Initial examination of a foal with an ALD should attempt to determine whether the deformity is manually reducible. If a reducible ALD is centered at the carpus or tarsus, the immature skeleton can be protected from additional trauma by treating the limb with rigid suppo rt. Surgical treatment may be required in foals with ALDs. In foals ol der than 6 months of age, correction may require additional surgical m anipulation; it might be necessary to consider a growth-retarding proc edure to achieve angular correction. Placement of a device that crosse s the growth-excessive (or normal) physis fora transient period can al low the growth-deficient aspect of the affected physis to match metaph yseal bone development. Complete exercise restriction is indicated for foals with severe ALDs. Deformities in-older growing horses are most likely to be caused by physeal abnormalities. Such patients may be bor n with correct limb conformation and acquire the ALD with age and grow th. Occasionally, rapid growth is stimulated by feeding high levels of concentrate. Radiographic evidence of partial physeal closure may ind icate that a case involves a physeal component of osteochondrosis or d ysplasia. Step and wedge ostectomies after physeal closure have been u sed successfully to correct ALDs in some older horses. These procedure s are best utilized to address angulations that originate in the metap hyseal and diaphyseal regions of an affected bone. External skeletal f ixators have been used to correct ALDs as well as limb-length deficien cies in humans and small animals. Recent study of a ring fixator may i ndicate that a viable external skeletal fixator is possible for future application to horses with ALDs.