Depending on the severity of the fracture, the clinical signs will vary from subtle to severe. Typically there is soft-tissue swelling of the stifle region due to the trauma which causes the fracture. Because the soft-tissue injury is present the fracture may be overlooked due to radiographs not always being taken initially. Joint effusion is present with most articular fractures.
If a patellar fracture is suspected, 3 radiographic views are required:
Tangential (as shown in the figure)
Ultrasonography is useful to determine injury of soft-tissue structures of the stifle. Additionally ultrasound examination is useful in identifying fractures of the patella and injury to the articular surface.