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.
Definition of incident for English Language Learners : an unexpected and usually unpleasant thing that happens : an event or disagreement that is likely to cause serious problems in relations between countries