Knee weakness

Hi, I began having knee pain about 14 months ago, when my baby was 6 months old. The discomfort got worse over the last 14 months. I had a lateral release nearly two weeks ago, but the month prior to this, my knee became so weak that I could not put a lot of pressure on it, making it difficult for simple walking. Since the surgery, you can see the muscle loss in my right knee. I do the exercises and it makes my knee shaky (maybe this is the process of muscle restoration??). I was just wondering if anyone has experienced the same and if so, how long it takes to build up the quads again. Thanks! Robyn