To compare the clinical outcome of posterior cruciate ligament (PCL) retention type and PCL substituting type using Advance(®) Medial Pivot (AMP) inner-axis knee prosthesis. A retrospective analysis was conducted on the cases of total knee arthroplasty (TKA) with AMP prosthesis in the Affiliated Hospital of Qingdao University from January 2011 to September 2016. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), American Knee Society Knee Score (KSS) clinical scores, KSS functional scores and knee-joint range of motion (ROM) before and after TKA, and Forgotten Joint Scores (FJS) after TKA were collected. The matching group was obtained by 1∶1 propensity score matching (PSM). Complete scoring data were obtained in 47 knees of CR group and 1 059 knees of CS group, there were statistical differences in age, sex, body mass index, preoperative WOMAC score, preoperative KSS function score and ROM between the two groups (all 0.05), except preoperative KSS clinical score (25±4 and 24±7, respectively, 0.82, 0.41). With the PSM matching, 37 knees in CR group and 37 knees in CS group were obtained. No significant differences in preoperative indexes were found between the matching groups (all 0.05). The WOMAC, KSS clinical scores, KSS functional scores and ROM after TKA in each matching group were all much better than those before TKA (all 0.05); no statistical differences existed in WOMAC, KSS clinical scores, KSS functional scores, ROM and FJS after TKA between the matching groups (all 0.05). One PCL injury was found in CR matching group after TKA. Incidence of complications in the CR matching group (8.1%) was higher than that in the CS matching group (2.7%), but there was no statistical difference (χ(2)=1.04, 0.31). When using AMP prosthesis, both CR insert and CS insert can obtain good clinical results in TKA. The potential risk of PCL injury and other complications after CR TKA makes it necessary for surgeons to carefully select an appropriate type of prosthesis.
