Please define what "post streptoccal reactive arthritis is?

Pain after strep: A few weeks after a strep infection (usually "strep throat"), some people will develop severe pain in one or more of their larger joints (knees, elbows, wrists...). These pains go away in time, only to reappear elsewhere. Persons who are having such symptoms should see a doctor to be sure they are not suffering from rheumatic fever instead -- a similar but probably separate condition.