Trial reportJournal of orthopaedic surgery and research2020
Mobile-bearing insert used with total knee arthroplasty does not rotate on the tibial tray during a squatting activity: a cross-sectional study.
Trial report in Journal of orthopaedic surgery and research, 2020. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 6 papers, 1 of them a synthesis that pooled it.
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
6 citing papers in PubMed, 1 synthesis or guideline pooled it.
- No difference between mobile and fixed bearing in primary total knee arthroplasty: a meta-analysis.Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA · 2022Pooled it
- Comparison of efficacy and cost-effectiveness between mobile-bearing and fixed-bearing unicompartmental knee arthroplasty for elderly patients with knee osteoarthritis: a retrospective cohort study.Frontiers in surgery · 2026Article
- Computational Study of Stress Distribution in Polyethylene Elements Due to Metal Components of Knee and Hip Implants Made from Different Metal Alloys.Materials (Basel, Switzerland) · 2025Article
- Optimizing outcomes in total knee arthroplasty: the role of patellar resurfacing and tibial ınsert type.Revista da Associacao Medica Brasileira (1992) · 2025Article
- Effect of design and surgical parameters variations in mobile-bearing versus fixed-bearing unicompartmental knee arthroplasty: A finite element analysis.Journal of experimental orthopaedics · 2024Article
- Mobile medial pivot (lateral slide) type total knee arthroplasty exhibits a medial pivot pattern: three-dimensional motion analysis using cadaveric knees.Journal of experimental orthopaedics · 2022Article
Corrections and comments
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Authors and funding
6 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundTotal knee arthroplasty (TKA) is commonly performed around the world. Implant designs include fixed-bearing and mobile-bearing. Mobile-bearing design was developed as a rotating platform that allows axial rotation of the insert around the longitudinal axis. This phenomenon may limit full exploitation of the characteristics of the mobile-bearing insert, which may cause wearing and reduce longevity. However, there is limited knowledge on rotational behavior of the polyethylene mobile-bearing insert under weight-bearing conditions. We aimed at determining the rotational motion of each component at full extension and flexed positions during a squatting activity after TKA.
methodsThis study was a cross-sectional study (level 4) involving patients with severe knee osteoarthritis scheduled to receive TKA. We examined 13 knees of 11 patients after mobile-bearing TKA (NexGen LPS-Flex, Zimmer Inc.) at 10 weeks and 1 year postoperatively. Four identical metallic beads were embedded into the insert. Wide-base squatting was chosen for analyses. Three-dimensional in vivo poses of the prostheses were created using a 3D-to-2D registration technique. During flexion, rotation of the femoral component relative to the insert (FEM/INS) and tibial component (FEM/TIB) as well as insert rotation relative to the tibial component (INS/TIB) were computed. Repeated measure 2-way ANOVA and post hoc test was used.
resultsIn the fully extended position, FEM/INS was significantly smaller than INS/TIB both at 10 weeks (- 0.3° vs. 6.3°, p = .013) and 1 year (- 0.8° vs. 4.9°, p = .011), respectively. During the squatting activity, rotation motions of FEM/TIB, FEM/INS, INS/TIB were 5.7°, 5.9°, and 1.8° at 10 weeks and 6.3°, 5.5°, and 1.6° at 1 year, respectively. Rotation motion of FEM/INS was significantly greater than that of INS/TIB at both 10 weeks (p < .001) and 1 year (p < .001).
conclusionsThe mobile-bearing insert enhances the compatibility of FEM/INS in extension; the amount of INS/TIB rotation is significantly smaller than that of FEM/INS during a squatting activity. This information will inform surgeons to take caution to perform TKA with a fixed insert in which 6.3° of rotational offset would be added to the rotational alignment at FEM/INS at full extension.
trial registrationUMIN-CTR, UMIN000024196. Retrospectively registered on 9 September 2016.
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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.