Fig 2.

After introduction of the arthroscope into the bone cavity, vision is often impaired by fat tissue in case of intraosseous lipoma (left picture). After irrigation and endoscopic removal of the fat tissue, residual calcifications can be identified (red arrows). The term “ossifying lipoma” is sometimes used synonymously. The viewing portal (anterior) is on the same line in the anterior-posterior direction as the working portal (posterior). In this figure, all instruments (probe, shaver, and grasper) are introduced over the posterior portal.