A one-year-old German Shepherd is presented with a two-week history of lameness. Although the dog limps on the right foreleg as it enters the exam room, the owner reports that the dog was lame on the left hindleg last week. On physical exam, the dog reacts painfully on palpation of the long bones of the right foreleg. Which one of the following choices is the most likely diagnosis?
一只一岁大的德国牧羊犬有两周的跛行病史。这只狗在进入检查室时表现右前肢跛行,但是主人说这条狗上周是左前肢跛行。 在体检中发现,狗对右前肢长骨的触诊有疼痛表现。以下哪种选择是最可能的诊断?