Greetings and welcome to justanswer,
The osteoarthritisof the knee may cause swelling, pain and stiffness of the joint as the symptoms.The treatment is symptomatic like medications, exercise and surgery in some cases.
The other causes should also be ruled out like venous thrombosis, arthritis, inflammation, etc.
Here is the link for more information
symptoms of osteoarthritis
Let me know if you have any doubt.
The ankle swelling may be due to the other causes as well like electrolyte imbalance, hypoalbunemia, congestive heart failure, renal failure, etc.
You may have the relevant investigations done like serum electrolytes, 2d echo of heart, serum urea, creatinine, to know the associated abnormality afer consulting your doctor.
The treatment depends on the underlying cause.