How To Stop Pus Discharge After Knee Cap Removal?

I was in a bike accident 5 years ago and my total knee cap was removed. Over the years the pus continues to leak out of the hole where the knee cap was. What can be done for this issue as it is not getting any better and sometimes the leakage is a large quanity. Can you please advise...I am a 44 year old male in a third world country. I am 6ft tall have lost most considerable amt of weight since accident. maybe weigh about 135 lbs.