When you are on a cycle of AAS your body starts to convert excess testosterone to estrogen with the help of an enzyme called Aromatase or estrogen synthetase. This results in higher than normal levels of estragen in a male's body which has several side effects. One of these side effects is water retention. Your ankels are swollen because of this.

Taking an Aromatase Inhibitor like Aromasin,arimidex or Letrozole will solve your problem. However, remember Letro is very strong and should preferable be taken only in the case of Gyno.

Hope this helps.