Post knee surgery problem

[Janeyb63]

Hi there my husband underwent partial knee replacement surgery 10yrs and then second knee 6years ago. his knees have been fine and he started gentle running again after many years of not being able to due to pain. 5years ago whilst jogging he experienced a near fatal anaphylactic shock and was later diagnosed with exercise induced anaphylaxis but only after eating wheat.
All has been well for a number of years but then a couple of wks ago another problem occurred. He has extremely swollen and stiff knees and rock hard calves. (Both legs at the same time) No sign of any redness or heat but this has resulted in him not being mobile. He is extremely distressed. Wondering whether a delayed reaction to the implants maybe??? Do you have any idea what could be causing this.
Many thanks
Jane burke