Bone bruise in knee

Hey guys, a few months ago at football practice I hyperextended my knee and was originally told by my athletic trainer that it was a patellar tendon strain. I didn’t feel too much pain, just stiffness and some slight pain during some movements. I rehabbed it for a couple weeks then I came back and I hyperextended my knee again at practice and it hurt much worse than the first time. My knee felt really stiff and I had some pain putting weight on my knee, and when flexing and extending my knee. After a few days the pain pretty much wore off, and my knee just felt weak and I just felt this pressure sensation in the sides of my knee when I put weight on it My athletic trainer and the team doctor both said it’s most likely a bone bruise because my knee felt stable and my ligaments seem fine. So I began rehabbing again for roughly a month, and when I was finally back to full-go last week I hurt my knee again while extending during my game on Saturday. It doesn’t feel as bad as the last time I hurt it, it feels weak and stiff sometimes and I feal pressure and some pain when I put too much of my weight on it. My question is, if it is just a bone bruise why do I keep re-aggravating it? Do you think an MRI would be necessary in this situation? I am just curious because I didn’t think a bone bruise would make my knee more susceptible to reinjury because I felt pretty much back to 100% because I was going through practices and games with no pain and then I all of a sudden I hurt it again. If you guys could offer some guidance I would really appreciate it!