What Causes Pain From Knee To Ankle After An MCL Surgery?

In June 2014. I had MCL surgery due to fractured right knee patella. I had PT and did everything as instructed by ortho doctor. However, I am now suffering from constant aches from my knee to top of ankle and also the inside groin. The worst part is the excruciating pain from my knee locking up. Sometimes, I wonder if it will straighten again. What could be happening?