Abstract: Objective  To investigate the effect of posterior cruciate ligament retaining(CR) and posterior cruciate substituting(PS) total knee arthroplasty(TKA). 
Methods  A total of 80 patients with knee osteoarthritis(KOA) underwent unilateral TKA, including 40 patients with CR-type prosthesis as CR group, and 40 patients with the PS prosthesis as the PS group. The duration of operation, intraoperative blood loss and drainage volume of the two groups were compared. The hospital for special surgery knee score(HSS) and knee joint activity were recorded at 1 and 3 months after operation. Knee activity and visual analog scale(VAS) at 3 and 7 d after operation were recorded; postoperative hemoglobin(HB) decline and postoperative subcutaneous ecchymosis, joint swelling, lower extremity venous thrombosis and other complications were recorded. They were followed up for six months, and the patient satisfaction was assessed using the Western Ontario McMaster university osteoarthritis index(WOMAC). 
Results  The decrease of HB in the CR group was significantly lower than that in the PS group after operation(P＜0.05). There was no significant difference in the duration of operation, preoperative HB and postoperative drainage between the two groups(P＞0.05). The VAS score of the CR group was lower than that of the PS group(P＜0.05). There was significant difference of VAS score between the two groups and different time points(P＜0.05), and the difference of interaction between groups, time points and time points between groups were not statistically significant(P＞0.05). There was no significant difference in the knee joint activity of the CR group and the PS group before operation, as well as in in HSS scores between two groups(P＞0.05). The knee joint activity in the CR group was less than that in the PS group at 6 months after operation(P＜0.05), and there was no significant difference in the HSS score as compared with the PS group(P＞0.05). The incidence of subcutaneous ecchymosis and joint swelling in the CR group was lower than that in the PS group(P＜0.05). There was no significant difference in the rate of incision healing and the incidence of venous thrombosis in the lower extremity compared with the PS group(P＞0.05). At 6 months after operation, the satisfaction rate of patients in the CR group(87.5%) was higher than that in the PS group(67.5%)(P＜0.05). 
Conclusion  CR prosthesis can retain the proprioception, reduce the amount of blood loss, pain and postoperative complications. PS prosthesis is more advantageous in improving knee joint mobility. In clinical application, the indications should be strictly controlled, and the level of prosthesis should be selected by the comprehensive skill level of the physician.

Key words: arthroplasty, replacement, knee, osteoarthritis, posterior cruciate ligament