The treatment of patients with severe flexion contracture of the rheumatoid knee, deprived of ambulation for long periods of time, is challenging. Based on three cases, we indicate the potential risks of posterior dislocation of the knee after total knee arthroplasty. In this pathological condition, surgeons must carefully select the type of implant in order to avoid this serious complication. We also emphasize the importance of working on disuse muscle atrophy of trunk (back, abdominal) and lower limbs, both of which play an integral role in ambulation. The personality of each rheumatoid patient should be carefully considered when considering surgical and rehabilitation options.