What Causes Knee Stiffness After Minescectomy ?

I had a minesectomy 5 months ago and am having stiffness in the knee to the point I cannot walk downstairs, get up from a chair or out of the car. I recentl had another MRI which showed that there is a problem with the cartilege and that there is something wrong with the minescus ligament. I have not met with the specialist as result of the MRI. Can you advise as to what the prognosis may be? My family physcian feels that more surgery will be needed. I do hope that I will not require a knee replacement at this time in my life. I am 60 years of agae.