Talk to Orthopedic Surgeon on Severe Knee Pain

Asslam-o-alaikum, My mother has been facing left knee problem for more than 6 years, now she is in condition to have severe knee pain almost all time, she is unable to walk properly (hardly bear to put few steps at home), and using different pain killers prescribed by multiple doctors, with knee bone she has pain in nearby muscles. Till now, have seen through various orthopaedic doctors, few suggested knee replacement and few stated to keep herself walking without surgery as she weighs 97 KG with a height 4' 10'' and has diabetes for 7 years almost. I want/seek an honest suggestion about what to do to keep her walking and pain relief. Doctors are recommending surgery while I have few patients' reviews (who have gone through knee surgery) that do not favoring this process as even after surgery patients feel pain, muscle stiffness or even infection in their knees after operation.