Trabecular Metal in Total Knee Arthroplasty Associated with Higher Knee Scores: A Randomized Controlled Trial

Abstract

Background Porous tantalum is an option of cementless fixation for TKA, but there is no randomized comparison with a cemented implant in a mid-term followup. Questions/purposes We asked whether a tibial component fixed by a porous tantalum system might achieve (1) better clinical outcome as reflected by the Knee Society Score (KSS) and WOMAC Osteoarthritis Index, (2) fewer complications and reoperations, and (3) improved radiographic results with respect to aseptic loosening compared with a conventional cemented implant.Methods We randomized 145 patients into two groups, either a porous tantalum cementless tibial component group (Group 1) or cemented conventional tibial component in posterior cruciate retaining TKA group (Group 2). Patients were evaluated preoperatively and 15 days, 6 months, and 5 years after surgery, using the KSS and the WOMAC index. Complications, reoperations, and radiographic failures were tallied. Results At 5-year followup the KSS mean was 90.4 (range, 68-100; 95% CI, ± 1.6) for Group 1, and 86.5 (range, 56-99; 95% CI, ± 2.4) for Group 2. The effect size, at 95% CI for the difference between means, was 3.88 ± 2.87. The WOMAC mean was 15.1 (range, 0-51; 95% CI, ± 2.6) for the Group 1, and 19.1 (range, 4-61; 95% CI, ± 2.9) for Group 2. The effect size for WOMAC was À4.0 ± 3.9. There were no differences in the frequency of complications or in aseptic loosening between the two groups. Conclusions Our data suggest there are small differences between the uncemented porous tantalum tibial component and the conventional cemented tibial component. It currently is undetermined whether the differences outweigh the cost of the implant and the results of their long-term performance.

The Mark Coventry Award

“…Highly porous metal tibias (both uncemented and cemented) were no different from traditional cemented modular tibial modular components in terms of survivorship at 5 years using a intention-to-treat analysis (96.8% [1]; 97.6% [2]; 96.7% [3]; p = 0.59). A per-protocol analysis revealed that no highly porous metal tibia was revised for aseptic loosening.…”

“…Table 3. Clinical and radiographic results at the latest followup tibia or a traditional modular cemented tibia, FernandezFairen et al [3] found no difference in durability at 5 years. At a minimum 5 years followup, a prospective analysis of 100 patients aged \ 55 years with an uncemented trabecular metal tibia by Kamath et al [6] found 97% survival for all causes and 100% survival with aseptic loosening of the tibia as the endpoint.…”

“…Dunbar et al [2] We found that TKA with a highly porous metal tibial component provided reliable clinical outcomes as assessed by clinical outcomes scores, ROM, prevalence of stiffness, and prevalence of complications at 5 years when compared with a traditional cemented modular tibial component and that is in general agreement with the preponderance of data available at midterm followup from other centers. The randomized clinical trial done by Fernandez-Fairen and colleagues reported higher Knee Society scores and better WOMAC scores at 5 years with an uncemented trabecular metal tibial component versus a traditional cemented modular tibial component [3]. The magnitude of those reported differences was relatively small and the clinical implications of those small differences can be debated but are likely best characterized as trivial.…”

To Cement or Not? Two-Year Results of a Prospective, Randomized Study Comparing Cemented Vs. Cementless Total Knee Arthroplasty (TKA)

“…Two-year outcome studies using radiostereometric analysis data have demonstrated excellent fixation with only mild subsidence among nonmodular trabecular metal tibial trays [7][8][9][10][11][12][13][14][15][16]. Recently, modular trabecular metal tibial components have become available for clinical use (Fig.…”

“…The orthopedic literature currently includes several prospective, randomized series comparing cementless and cemented fixation at various follow-up intervals [7,[11][12][13][14][17][18][19][20][21]. Currently, there are no published studies evaluating modular trabecular metal tibial trays.…”