Clinical outcomes and survival comparison between NexGen all-poly and its metal-backed equivalent in total knee arthroplasty

Abstract

Purpose This study aims to compare total knee replacement (TKA) with NexGen All-Poly (APT) and NexGen Metal-Backed (MBT) in terms of implant survivorship, reasons leading to implant failure and functional results of defined age categories. Methods A single-centre, retrospective evaluation of 812 patients who underwent knee replacement with NexGen CR between 2005 and 2021, comparing a modern congruent APT component to a modular MBT equivalent component using a similar surgical technique at a notable mean follow-up duration. Implant survival, functional outcomes using the Knee Society Score and range of motion were evaluated and compared in different age categories. Results Of the 812 NexGen CR TKAs performed at our institution, 410 (50.4%) used APT components and 402 (49.6%) MBT components. The survival rate of NexGen APT was 97.1% and that of NexGen MBT was 93.2% (p = 0.36). Removal of the implant occurred overall in 15 cases, for MBT in ten cases, and for APT in four cases. The FS was proved to be significantly higher when APT components were implanted in younger patients than for MBT (p = 0.005). A similar range of motion between the components was recorded (p = 0.1926). Conclusion Under defined conditions, we measured the clinical results of implants from a single manufacturer implanted in a single department using a similar surgical technique. Considering the limitations, we suggest that all-polyethylene tibial components are equal or even superior to metal-backed ones across the examined age categories.

Implant Preference and Clinical Outcomes of Patients with Staged Bilateral Total Knee Arthroplasty: All-Polyethylene and Contralateral Metal-Backed Tibial Components

“…A previous study described excellent long-term clinical results and survivorship of APTs [10]. Moreover, in a clinical comparison of 812 patients with NexGen TKA APTs and MBTs, we suggest that APTs are equal or even superior to metal-backed components across the age categories [3]. Further examination of the topic in a biomechanical analysis on APTs showed a similar induced response in patients of the 60-70-year-old age groups as well as remodelling and modelling of the periprosthetic tibia, which is a beneficial factor in implant survivorship [11].…”

“…Most total knee replacements have been performed with metal-backed tibial components (MBTs). All-polyethylene tibial components (APTs) are primarily implanted in older and lowdemand patients [3]. Numerous studies have compared MBTs and APTs, describing similar clinical outcomes and implant survivorship [4][5][6].…”

Biomechanical comparison of all-polyethylene total knee replacement and its metal-backed equivalent on periprosthetic tibia using the finite element method

“…The clinical outcomes of TKA with APT have been described to be comparable to or even better than those with MBT [4,5]. In our institution, the average age of the patients on the day of implantation of TKA NexGen APT was 75.4 years and only 12% were younger than 72 years.…”

“…On the contrary, the average age of the patients on the day of implantation of TKA NexGen MBT was 65.9 years and only 11.75% were older than 72 years (Fig. 1) [4].…”

Extensive subcutaneous emphysema of the thigh as a rare complication following total knee arthroplasty: A case report

“…TKA is a common treatment for knee osteoarthritis and is currently performed at a rate of 100,000 per year in the UK and 700,000 per year in the US [ 3 ]. TKA has a long history of use, and the results have been improving due to advancements in surgical techniques and models [ [8] , [9] , [10] ]. While the risk of complications has decreased accordingly, certain complications such as infection and deep vein thrombosis are still inevitable [ 1 , 4 ].…”