Humeral Head-Split Fracture in Two Dogs.

Two skeletally immature female dogs were each investigated for chronic weight-bearing thoracic limb lameness. The first patient was lame for 2 months following a tumble whilst playing, and the second patient had been intermittently lame since 3 weeks of age. In both cases, radiographic examination of the shoulder revealed fissuring of the caudal humeral head consistent with an incomplete proximal humeral Salter-Harris type IV fracture with an Enoki-mushroom-like appearance of the caudal fragment, where two heads rise from a common stem. There was secondary neoarthrosis of the caudal humeral head fragment with the glenoid rim of the scapula. Humeral head-split fracture is an unusual fracture pattern that rarely occurs in skeletally immature patients, and conservative management appears to result in reasonable short-term outcomes. The role of early detection and surgical intervention remains unknown.