What Is Cavitation?
If you've ever cracked your knuckles, you've created cavitation. This phenomenon can occur infrequently during the distraction procedure. As the distractor device imposes a lateral distractive force on the hips, the creation of negative pressure can cause a void to form in the synovial fluid in the joint. This void appears as an air bubble on the radiograph. Cavitation is not painful and does not cause short or long term damage to the joint. It occurs infrequently, and resolves within 24 hours.
Cavitation is problematic only because it causes the DI measurement to be unreliable. A cavitated joint can have a false increase in the DI.
Cavitation on the Radiograph
Arrow indicates cavitation
The appearance of cavitation on a radiograph may be unilateral (one hip), or bilateral (both hips).
If cavitation is unilateral,
- No DI will be generated for the cavitated hip.
- An interpretation will be derived from the non-cavitated hip.
If cavitation is bilateral,
- No DI will be generated for either hip.
- It is recommended that the evaluation be repeated in 24 hours.