Contributors: Justin Goggin, Patsy Whelehan
Species: Canine | Classification: Techniques
- A high resolution film-screen combination is required in small and medium sized dogs.
- A grid with fast film-screen combination is advisable in large-breed dogs (when patient thickness >10 cm use a grid to reduce scatter).
- Joints at both ends of the bone should always be included.
- Soft tissues should be included.
- General anesthesia or heavy sedation is advised.
- The film should be correctly exposed and developed, and free from movement blur and artefact.
- The anatomical marker must be clearly visible, along with the patient's identification, the date, and the name of the hospital or practice.
- → Fracture.
- → Developmental bone disease, eg panosteitis Panosteitis.
- → Neoplastic bone disease .
- → Soft tissue neoplasia invading bone.
- → Osteomyelitis.
- → Metabolic/congenital bone disease.
- Readily available.
- Frog legged ventrodorsal hip view Radiography: pelvis for femoral neck fractures.
- Dependent upon the method of chemical restraint (GA or sedation).
- 10-15 min or longer, dependent upon skill of radiographer.
Criteria for choosing test
Is the examination appropriate?
- Can you make the diagnosis without it?
- Can it tell you what you need to know?
- Will your management be affected by the radiological findings?
- Essential as part of a complete two-view study to detect and characterize disease in this area.
- Essential as part of a complete study to characterize and detect disease.
- Radiographer or veterinary nurse/technician carrying out radiography.
- X-ray machine.
- Cassettes with high resolution or fast screens, depending on size of patient.
- Processing facilities.
- Immobilization and positioning aids: sandbags, foam wedges, cloth tape or rope.
- Protective clothing (lead-rubber aprons, gloves, thyroid shields).
- High output X-ray machine.
- High resolution earth screens.
- Bucky table.
- Grid for patients >10 cm thickness.
- Automatic processing facilities.
- Film labelling system.
- X-ray film.
- Pharmaceuticals for chemical restraint.
- 1-2 competent people.
- Foam wedges.
- Tying tapes.
- Positioning trough.
Step 1 - Lateral
- Position the patient in lateral recumbency on the side to be examined and immobilize. Alternatively, position the thorax in dorsal recumbency in a trough and rotate the patient towards the affected side, abducting the femur.
- Use a sandbag and/or tie to hold the contralateral limb dorsally away from the field.
- Flex the hip and stifle on the affected side slightly.
- Use padding under the dorsal pelvis and the distal limb as necessary to achieve a true lateral position of the femur, parallel to the film .
- Center the vertical beam at mid-shaft .
- Collimate to include the hip and the stifle, as well as the soft tissues cranial and caudal to the shaft .
Step 2 - Craniocaudal
- Position the patient in dorsal recumbency in a trough.
- Rotate slightly away from the affected side and immobilize.
- Extend the affected limb caudally and secure with a tie.
- Further adjust the position of the trunk to ensure that the femur is in a true craniocaudal position.
In the likely event that the femur is not horizontal, angle the beam until it is perpendicular to the shaft and elevate the caudal edge of the cassette to bring it as near perpendicular to the beam as possible (when not using a grid).
This technique is unlikely to result in an undistorted view of the stifle. Where this is necessary it is important to center separately for the stifle, as with all joint radiography.
- Center the beam at mid-shaft .
- Collimate to include both joints and the lateral and medial skin surfaces.
Reasons for Treatment Failure
- Failure to label film properly.
- The most common problem here is inadequate extension of the hip and/or the stifle for the craniocaudal view. This is often due to the limitations of the patient's condition. While angulation of the beam and film can help, a distorted view is sometimes still obtained. It may be necessary to resort to a separate caudocranial view of the distal femur (see stifle Radiography: stifle ).
- Inadequate sedation.
- Incomplete study (only one view).
- Poor processing.
- Equipment failure.