Objective To investigate the surgical planning and the mid-term effectiveness of four major lower extremity arthroplasties (4JA) in patients with rheumatoid arthritis (RA). Methods A clinical data of 25 patients with RA, who received 4JA and were followed up more than 3 years between June 2012 and September 2018, was retrospectively analyzed. There were 3 males and 22 females, with an average age of 48.6 years (range, 27-80 years). The body mass index ranged from 16.0 to 28.4 kg/m2, with an average of 20.48 kg/m2. The duration of RA ranged from 2 to 35 years (median, 21 years). There were 8 cases (12 sides) of knee valgus, 6 cases (12 side) of acetabular retraction, and 5 cases (10 sides) of hip stiffness. Among them, 20 patients underwent hip surgery first, and 5 patients underwent knee surgery first. Hip joint function was evaluated by Harris score, Hip Disability and Osteoarthritis Outcome Score (HOOS), hip range of motion, and Trendelenburg sign; knee joint function was evaluated by American Hospital for Special Surgery (HSS) score, knee range of motion and muscle strength, and a timed up and go (TUG) test was performed at last follow-up. X-ray films were used to observe whether the prosthesis was loose or displaced. Results All 25 patients completed 4JA. Only 1 patient (1 side) had incision infection after operation, 3 patients (3 sides) had proximal femur fractures during operation. All patients were followed up 3.0-8.8 years, with an average of 5.8 years. At last follow-up, the Harris score, HOOS score, and range of motion of flexion, extension, and abduction of the hip joint significantly improved when compared with those before operation, and the patients with positive Trendelenburg sign decreased. The HSS score and range of motion of flexion and extension of the knee joint also significantly improved when compared with those before operation. There were significant differences in all indexes between pre- and post-operation (P<0.05). The muscle strength was grade V. The TUG test ranged from 7.8 to 15.34 seconds (mean,10.79 seconds). X-ray films showed the prosthesis was not loose or displaced. Conclusion When RA patients receive 4JA, adequate preoperative evaluation, rational selection of the timing and sequence of surgery, and maximal restoration of lower limb alignment can achieve good mid-term effectiveness.