Can you give me some suggestions of exercises to strengthen my knee in the gym?
Quadriceps strengthening is usually the key to happy knees. I like squats and lunges – not necessarily with much, if any weight, but more for a lot of reps. Those can strengthen the hamstrings as well, though isolated hamstring curls are not a bad idea either. I don’t like seated knee extensions. They tend to make a lot of knee pain worse, and eliminating that exercise alone is often enough to fix a lot of knee pain.