Reason For Elevated WBC After Knee Replacement

my husband had knee replacement surgery on june 7th. he had stomach issues with illius/urinary tract infection and now white blood cell count is still elevated. we know that all these things including surgery can cause w.b.c. count to be elevated but stomach issues have been resolved, uti is clear so what can be causing this? He has a place on this arm that looks like "cellulitis: Can this cause his w.b.c. count to be elevated?