I had a meniscus repair one yr ago wear a knee brace for instability had physical therapy 3 times constant pain what about knee replacement?

Unlikely: Knee replacement is done to treat arthritis of the knee. If you are 33 years old, it is unlikely that you have severe arthritis in your knee unless you had a major trauma in the past or have had multiple surgeries. Knee arthritis is easily diagnosed with a plain x-ray. This is where you should begin to see if you have evidence of arthritis.