Psoriasis: The most common skin disorder that also affects the joints, including the knees, is psoriasis. Although certainly not all patients with psoriasis will develop joint problems, psoriatic arthritis may cause knee pain and swelling. ...Read more.
Definition of accident. 1  1a : an unforeseen and unplanned event or circumstance Their meeting was an accident.b : lack of intention or necessity : chance They met by accident rather than by design.
legal Definition of occurrence : something that takes place; especially: an accident, event, or continuing condition that causes personal or property damage that is unintended or unexpected from the standpoint of an insured party making a claim