Which kind of exercises can a total knee replacement patient do to firm lower body?

A lot: Avoiding excessive cutting and pivoting and pounding activities (like running and jumping) are important. Otherwise there aren't many limitations after knee replacement. Biking, swimming, walking, and elliptical trainers are all excellent exercises for leg strengthening.

Quads and hamstrings: For the knee, quad and hamstring strengthening is recommended, especially progressive resistance (e.g. Theraband, kinesis bands). Cycling, elliptical and swimming are great for cardio.

Stationary bike: I really like the stationary bike as a form of exercise for knee replacement patients. Body weight is eliminated, quad strength is improved and weight can be lost, all at the same time.

Low impact : You can bike, swim, dance, elliptical, perform leg presses, quarter squats with low weights, hamstring curls, calf raises, abductor and adductor exercises, knee extensions, pilates, yoga, tai chi. Many options. Avoid running or jogging.