To compare the accuracy of three-dimensional(3D)patient-specific instrumentation(PSI) with conventional instrumentation concerning re-established lower limb alignment and prosthetic component positioning after total knee arthroplasty(TKA).

The randomized controlled trials that comparing 3D PSI with conventional osteotomy instrumentation concerning the lower limb alignment and clinical efficacy following TKA were searched through PubMed, Embase, CoChrane Library, CNKI, Chinainfo and other accessible electronic databases. The articles were precisely screened according to the inclusion criteria(the research types were randomized controlled studies, the research objects were end period osteoarthritis or rheumatoid arthritis patients who met primary TKA, the intervention and control measures were PSI or conventional instrumentation, the outcome measures included at least lower limb mechanical axis outliers) and exclusion criteria(the studies that did not meet the criteria mentioned above); the quality was assessed on the basis of the Jadad rating scale. Related data were extracted and analyzed by Review Manager 5.3, the relative risk (RR) and 95% confidence interval (CI) were evaluated for count data such as lower limb mechanical axis and prosthetic component outliers, the mean difference(MD) and 95% CI were calculate for continuous variables such as knee function score and operation time. The statistical results were reviewed in the end.

Eleven articles, including 12 trials were enrolled in this study. There was no statistically significant difference between PSI and conventional instrumentation in the post-operative hip-knee-ankle axis(lower limb mechanical axis) outliers[RR=0.88, 95%CI(0.65, 1.19), P>0.05]; the coronal femoral component outliers[RR=0.76, 95%CI(0.57, 1.02), P>0.05]; the coronal tibial component outliers[RR=1.19, 95%CI(0.68, 2.09), P>0.05]; the OKS scores at 3-month follow-up[MD=0.04, 95%CI(-1.63, 1.72), P>0.05] after TKA between PSI and conventional instrumentation. The post-operative femoral component rotation outliers indeed showed statistical difference [RR=0.55, 95%CI(0.33, 0.94), P<0.05].

PSI is more accurate than conventional osteotomy instrumentation in femoral component rotation after TKA.