Limited information is gained by vacuum pneumarthrography of the knee.
1. Absence of the Vacuum space indicates fluid which may not be detected otherwise.
2. The meniscus can be demonstrated in the absence of fluid. Neither weakening nor relaxation of the ligaments is a prerequisite.
3. Pathological irregularities of the meniscus and articular cartilaginous surface can be identified.
4. Visualization is limited to the rigid structures and does not include synovial extensions or fat pads, as does the injection technique.
5. The examination can be done simply, quickly, and without the use of surgical technique or apparatus.
Spontaneous vacuum phenomena occur only in abnornmal hip joints and demonstrate irregularities of the cartilage which would otherwise not be perceptible by roentgenographic examination.
This is a preliminary report only, which is submitted to stimulate interest in the possible Clinical significance of the vacuum phenomenon.