To analyse the results of posterior cruciate ligament-retained mobile-bearing total knee arthroplasty (TKA) in treatment of rheumatoid arthritis (RA) and to solve the problems often encountered during surgery.
From February 1999 to August 2005, the clinical data from 73 patients with RA undergoing TKA were analysed retrospectively. In 73 patients, 38 patients were treated with posterior cruciate ligament-retained mobile-bearing prosthesis (group A), while 35 patients were treated with posterior stabilized fixed-bearing prosthesis (group B). Another 70 patients with osteoarthritis (OA) treated with an posterior cruciate ligament-retained mobile-bearing prosthesis served as controls (group C). In group A, there were 8 males and 30 females with an average age of 56.5 years and an average disease course of 16.8 years. In group B, there were 6 males and 29 females with an average age of 57.3 years and an average disease course of 17.1 years. In group C, there were 37 males and 33 females with an average age of 65.4 years and an average disease course of 10.8 years. There was no significant difference (P > 0.05) in general data between groups A and B, but there were significant differences (P < 0.05) when compared with group C.
In groups A and B, 2 cases (5.3%) and 1 case (2.9%) had poor healing of incision, respectively; in group C, all cases had good healing of incision. There were significant differences in healing rate of incision between groups A, B and group C (P < 0.05). All patients were followed up 7.6 years on average (range, 3.5-10.5 years). Deep infection occurred in 1 case respectively in 3 groups, showing no significant difference (P > 0.05). Posterior instability occurred in 1 case (2.6%) 5 years after operation in group A and 2 cases (2.9%) 9 years after operation in group C, and no posterior instability occurred in group B; showing significant differences between groups A, C and group B (P < 0.05). There were significant differences (P < 0.05) in knee score, Feller patellar score, and anterior knee pain score between pre- and postoperative values among groups A, B, and C. There were significant differences (P < 0.05) in the function scores between pre- and post-operative values in 3 groups, between groups A, B and group C pre- and post-operatively.
Posterior cruciate ligament-retained mobile-bearing TKA can yield satisfactory clinical results in treatment of RA at intermediate-term follow-up. This mobile-bearing prosthesis has a low prevalence of posterior instability and a good outcome for anterior knee function without patellar resurfacing.