Aim: A meta-analysis comparing the outcomes of patients undergoing cruciate retaining (CR) versus posterior stabilized (PS) in primary total knee arthroplasty was performed. The outcomes of interest were the Knee Society Rating System, clinical (KSCS) and functional (KSFS) subscales, joint range of motion (ROM), surgical duration and further complications (anterior knee pain, instability and revision rate).
Materials and methods: The search was conducted in July 2018, accessing the following databases: Cochrane Systematic Reviews, Scopus, PubMed, EMBASE, CINAHL, AMED and Google Scholar. We included only clinical trials level of evidence I and II. During the statistical analysis, we excluded all the studies that affect negatively the I2 test, in order to achieve more reliable results. For the methodological quality assessment we referred to the PEDro score. The risk of publication's bias was evaluated by the funnel plots across all the comparisons.
Results: The PEDro score reported a good methodological quality assessment. The funnel plot detected a very low risk of publication's bias. We included in this study 36 articles, counting a total of 4052 patients and 4884 procedures. The mean follow-up term for both groups was 3.39 years. The ROM resulted in an overall estimate effect of 2.18° in favor of the PS group. The overall WOMAC showed a result in favor of the PS group. The overall estimate effect of the KSCS was 0.02% higher in the CR group. The KSFS showed an overall estimate effect of 2.09% in favor of the PS group. Concerning the surgical duration, the estimate effect resulted in 6.87 min shorter in the CR group. No differences were reported across the two groups regarding anterior knee pain, knee joint instability or revision rate.
Conclusion: Both the prosthetic implants provided to be a safety and feasible solution to treat end-stage knee joint degeneration. The PS implants reported improvements in the knee range of motion and a prolongation of the surgical time. No clinically relevant dissimilarities concerning the analyzed scores were evidenced. No statistically significant relevant differences in complications were detected.
Keywords: Cruciate retain; Posterior cruciate ligament; Posterior stabilized; Total knee arthroplasty.