Comparison of Clinical Outcomes of TKA Implantation: ATTUNE vs. SIGMA

Introduction

SIGMA type implants are among the endoprostheses with a strong position in the modern history of knee arthroplasty, with their excellent clinical results demonstrated by several studies. Since 2013, the ATTUNE system has also been available, representing the successor to SIGMA endoprostheses. It was designed to minimize potential unsatisfactory results that could occur with the implantation of SIGMA type endoprostheses or other knee endoprostheses available on the current market.

Among the innovative features of the ATTUNE system are the variable size of the polyethylene insert of the tibial tray thanks to a unique attachment system, a unique type of curvature of the radii of the femoral component improving implant stability, or a new type of patellar replacement reducing the risk of anterior knee pain syndrome.

Study Results

In their 2018 study, Carey and Harty compared ATTUNE and SIGMA endoprostheses in a cohort of 21 patients. The study is unique in that it was possible to compare the older and newer types of endoprostheses in 1 patient. All procedures were performed by the same surgeon in the same medical facility. ATTUNE endoprostheses showed a greater range of motion 6 months after the procedure compared to the SIGMA endoprosthesis (13 ± 11° vs. 10 ± 8°). For SIGMA endoprostheses, a significant increase in WOMAC score was observed, and for ATTUNE endoprostheses, the Oxford Knee Score was noted (8.9 ± 7.7 and 12.1 ± 8.4). Significant improvement was noted for both types of endoprostheses in the SF-12 scoring system. Overall, excellent results were achieved, but in direct comparison, ATTUNE endoprostheses showed superiority to the SIGMA system (1).

In their study, Bloch et al. compared the survival time of the implant in 500 SIGMA endoprostheses and the same number of ATTUNE endoprostheses over at least 2 years. ATTUNE type endoprostheses were observed to have a longer survival time compared to SIGMA implants. The ATTUNE endoprosthesis achieved a higher rating in the Oxford Knee Score, although it did not reach statistical significance (2).

Clatworthy published early results of implanting 40 ATTUNE endoprostheses and the same number of SIGMA endoprostheses. Patients with ATTUNE endoprosthesis implantation achieved greater flexion within the first 6 weeks post-operation, less pain, and higher functional scores at discharge from the medical facility; differences in later periods and other parameters were not statistically significant (3).

Conclusion

The results of the studies indicate that the ATTUNE type knee endoprosthesis shows better clinical outcomes compared to the older SIGMA implant. However, in several parameters, both of these endoprostheses achieve similar results, making the SIGMA type endoprosthesis still among the top-quality implants.

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CZ-2020-01-71

Sources:
1. Carey B. W., Harty J. A comparison of clinical- and patient-reported outcomes of the cemented ATTUNE and PFC SIGMA fixed bearing cruciate sacrificing knee systems in patients who underwent total knee replacement with both prostheses in opposite knees. J Orthop Surg Res 2018; 13 (1): 54, doi: 10.1186/s13018-018-0757-6.
2. Bloch B. V., Shahid M., James P. J. ATTUNE has improved implant survivorship and clinical outcome over PFC SIGMA: a single surgeon series of 1000 cases with minimum 2 years follow up. Available at: http://synthes.vo.llnwd.net/o16/LLNWMB8/US Mobile/Synthes North America/Product Support Materials/Charts/DSUSJRC02182608ATTUNE HAS IMPROVED IMPLANT SURVIVORSHIP.pdf
3. Clatworthy M. An early outcome study of the ATTUNE^® Knee System vs. the SIGMA^® CR150 Knee System. Available at: http://synthes.vo.llnwd.net/o16/LLNWMB8/US Mobile/Synthes North America/Product Support Materials/White Papers/DSUSJRC08140418 Early Outcome Study.pdf