The Knee
Interpreters have stated that seeing an 'event' or defect in the knee might relate to what is attributed to it. The strength of the knee's skin could indicate a strong livelihood, while its peeling might signify increased toil and fatigue. Thickening of its skin or the appearance of a tumor could be interpreted as gaining wealth after effort. For a sick person, seeing pain or an ailment in their knee might indicate their death. Generally, the knees are interpreted as representing physical strength, mobility, the quality of one's knowledge, and their health. Healthy and strong knees are a sign of travel, other activities, and overall bodily well-being.
Per Ibn Sirin's Muntakhab al-Kalam fi Tafsir al-Ahlam