What is X-ray?
An X-ray examination is an imaging procedure. Structures from inside the body are reproduced on a radiosensitive plate by absorbing the emitted radiation to a variable degree. Bone, which appears white on X-ray, is identified very easily. It is therefore termed “X-ray-dense“. Soft organs such as the intestine or bladder are shown less readily and these are seen better on ultrasound.
An advantage of X-ray is that it is not associated with any pain and does not injure the body. Most X-rays can be taken without an anaesthetic depending on the part of the body being X-rayed and the aim of the examination. Digital X-ray is generally used today. The images are no longer produced on a film that has to be developed but are produced on a digital plate. The result is therefore on the computer immediately after the examination and can be assessed by the vet.
When is the knee X-rayed?
The knee can be X-rayed to rule out certain diseases as part of the examination of an apparently healthy animal. This is done, for instance, when a dog is to be used for breeding. Depending on the breed association, this examination may be stipulated.
More often, however, it is done to find the cause when the animal has pain or limitation of movement. If the animal becomes lame or visibly has pain when the knee is touched, the veterinary surgeon will carry out a thorough examination. Apart from palpation, this usually includes an X-ray also. Even if the vet is relatively certain what the problem is, the X-ray provides further information: how severe is the disease? How badly damaged are e.g., ligaments or menisci (connective tissue shock absorbers) in the knee? How badly affected is the cartilage?
Possible diseases of the knee include e.g.
- Patellar luxation (dislocation of the kneecap)
- Osteoarthritis (cartilage damage, e.g., due to age or incorrect loading)
- Cruciate ligament tear
- Osteochondrosis dissecans (also a type of cartilage damage)