Survivorship and Functional Outcomes of Cementless versus Cemented Total Knee Arthroplasty: A Meta-Analysis

The purpose of this meta-analysis was to assess the evidence supporting the use of cementless versus cemented total knee arthroplasties (TKAs). Specifically, we evaluated (1) all-cause survivorship, (2) aseptic survivorship, and (3) functional outcomes (Knee Society Scores [KSS], Oxford Knee Scores, Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC] scores, and ranges of motion [ROMs]). A literature search was performed for studies that evaluated cementless versus cemented TKAs published between 2000 and 2017. Selected studies included three randomized controlled trials, three retrospective observational studies, and one prospective observational study that met the following criteria: (1) primary TKAs, (2) compared cementless and cemented TKAs, (3) implant survivorship that described the causes of failure, and (4) at least one functional outcome. To compare the two cohorts, pooled odds ratios (OR) and 95% confidence intervals (95% CI) were used to calculate tibial and femoral implant survivorship, and pooled mean differences (MD) and 95% CI calculated the functional scores and ROMs. Based on pooled data from the few number of studies, cementless TKAs had a better all-cause survivorship (OR = 0.37; 95% CI, 0.15-0.92) and tended to have a better aseptic survivorship (OR = 0.44; 95% CI, 0.17-1.14). However, this is likely due to the 83.3% weight of the single cementless study potentially influencing the analysis. There were no differences in terms of KSS knee (MD = 1.03; 95% CI, -1.13-3.20) or function scores (MD = 5.36; 95% CI, -3.75-14.51), Oxford knee scores (MD = 0.36; 95% CI, -3.84-4.56), or WOMAC scores (MD = 0.62; 95% CI, -0.87-2.11). Moreover, there was no difference in ROMs (MD = 1.47; 95% CI, -0.11-3.05). Cementless TKA had a better all-cause survivorship when compared with cemented fixation, and similar functional outcomes were demonstrated. However, these findings are based on only a few number of studies (n = 7). Therefore, additional prospective, randomized control trials need to be performed to best compare cementless versus cemented outcomes.