Читать книгу Fractures in the Horse - Группа авторов - Страница 65

Involvement of additional bones can substantially impact prognosis. For example, an axial proximal sesamoid fracture occurring concurrently with a displaced lateral condylar fracture is associated with a poor prognosis for return to athletic function [177]. Disruption of vasculature supplying the fracture site can slow or prevent healing or lead to avascular necrosis precluding the possibility of salvage. Examples include transection of the popliteal artery in femoral fractures [191] and thrombosis of palmar/plantar digital arteries in acute fetlock breakdown injuries [192].

Pathologic fractures occur through abnormal or diseased bones at lower loads than those that would cause fracture in healthy bones. Among the more common examples of conditions that predispose to complete fracture are neoplasia (e.g. osteosarcoma, lymphosarcoma and chondrosarcoma) and osteomyelitis [193–196]. Regionally, in California, a silicate‐associated systemic osteoporosis syndrome known as ‘bone fragility’ manifests with pathologic fractures [197]. Most affected horses have concurrent pulmonary silicosis and a history of exposure to soil containing cytotoxic silica dioxide crystals [198, 199]. Horses with pituitary pars intermedia dysfunction (PPID) or chronic hyperglucocorticoidism are also susceptible to pathologic fractures [200]. Fractures associated with a pre‐existing stress fracture or subchondral stress remodelling are also considered pathologic fractures.