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ANTEBRACHIAL pathology, in particular growth disturbance affecting the proximal or distal radial physes, is unusual. When present, it can result in a short radius and associated humeroradial and humeroulnar incongruency or a varus deformity of the distal limb (Vandewater and Olmstead 1983, Shields Henney and Gambardella 1990).
Over the past three years, one of us (SC) has reviewed a small number of radiographs from skeletally immature pugs that have thoracic limb lameness. The radiographic features appear to be an overlong radius with proximal and occasional distal radial physeal fractures, which remain minimally to mildly displaced (Fig 1). The distal ulnar growth plate appears to be unaffected. There appears to be a characteristic cranial and proximal displacement of the proximal radial epiphysis with subluxation of the radioulnar and humeroradial articulations and, on occasion, caudal and distal displacement of the distal radial epiphysis and subtle antebrachiocarpal joint subluxation.
Recently, we have examined two pugs, a 5.5-month-old female and a six-month-old male, with thoracic limb lameness due to this pathology. The duration of lameness was four and 12 weeks, respectively. The pathology was bilateral but more evident in one thoracic limb. In both cases the lameness appeared to be predominately due to pain associated with the physeal fracture(s) as opposed to elbow or carpal pathology. Both cases were managed successfully with restricted activity and NSAID medication, with lameness resolving as the physeal fractures healed, in spite of the persistence of elbow and, when present, carpal pathology.
Given the age at presentation, the radiographic features and the presence of minimal, if any, abnormal thoracic limb conformation, we hypothesise that the pathology could be due to radial overgrowth with respect to normal ulnar growth. This results in stress concentration at the radial physes, which subsequently fracture and mildly displace. By the time of clinical presentation the remaining growth potential is negligible, which allows the fractures to progress to union without intervention.
We suspect that this is an emerging condition in pugs. It would not appear to be confined to a particular demographic, as one of us (SC) had his initial experience of the condition while in Scotland. We are interested in learning more about the aetiopathogenesis of the condition, its possible presence in other dog breeds, and the management and outcome. We would welcome colleagues who have seen similar cases to contact us. We can be contacted at the address below, telephone 0121 712 7070 or e-mail: