Hi there,
I have dislocated my knee for 31yrs ouch! So I feel your pain! I just had sx 9 wks ago. They loosend one ligament on one side of my knee and tightend one on the other, and also brought a muscle over the ligament to make it tighter. They kind of packed my knee in sort of speak so it hopefully won't go out again. It was called a lateral release/vmo imbrication. You dislocated it only 2 times? Have you been going to pt to strengthen it? My MRI showed I had a shallow grove so nothing was really holding my knee in. If you are uncomfortable in his decision always get a second opinion, and get as much information as you can. This site is wonderful, and the people on here can help so much, and also lift your spirits when needed. Just when you think nobody understands someone on here will, even if it's a different surgery. Keep us posted on how you are doing.
Sending thoughts and wishes your way!