Evidence map›Paper›PMID 42899483›Full record

ArticleBone & joint research2026

Asymmetric metaphyseal cones versus medial modular block augment with central cone for medial tibial defects : a biomechanical comparison in varying bone quality.

Yi Ren, Chloe E H Scott, Nick D Clement, Shuqiao Xie, Pankaj Pankaj

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Article in Bone & joint research, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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1 · What the graph read from 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.

2 · The registry

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3 · Its place in the literature

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4 · The record

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5 · Who and what money

Authors and funding

5 authors.

Yi RenInstitute for Bioengineering, School of Engineering, The University of Edinburgh, Edinburgh, UK.ORCID 0009-0007-3108-4875
Chloe E H ScottEdinburgh Orthopaedics, Royal Infirmary of Edinburgh, Edinburgh, UK.ORCID 0000-0002-0012-1596
Nick D ClementEdinburgh Orthopaedics, Royal Infirmary of Edinburgh, Edinburgh, UK.ORCID 0000-0001-8792-0659
Shuqiao XieDepartment of Bioengineering, Imperial College London, London, UK.ORCID 0000-0001-6907-5586
Pankaj PankajInstitute for Bioengineering, School of Engineering, The University of Edinburgh, Edinburgh, UK.ORCID 0000-0002-9317-3909

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

Aims: Managing large medial tibial bone defects during total knee arthroplasty (TKA) remains technically demanding, particularly in elderly patients. This study quantitatively compares two reconstructive strategies: 'bridging' the defect using an asymmetric metaphyseal cone versus 'anatomical reconstruction' employing a symmetrical cone with a metallic block augment, and assesses their sensitivity to osteoporotic bone quality. Methods: A finite element model of a tibia with a standardized medial defect (Anderson Orthopaedic Research Institute (AORI) Type 2a) was adapted to simulate both configurations under physiological loading cycles in healthy and severe osteoporotic bone. Cumulative interface micromotion was quantified using a coordinate-based post-processing algorithm that decouples normal separation from tangential shear. A parametric sweep of the tangential contact clearance evaluated near-surface biological interaction zones without additional simulations. Results: In healthy bone, both strategies demonstrated adequate stability with micromotions predominantly below 50 μm. In osteoporotic bone, the asymmetric cone exhibited a loss of stability, characterized by intermittent lift-off during walking and excessive tangential shear during stair descending. This instability induced a toggle effect at the distal stem. The augmented symmetrical cone maintained stable fixation regardless of bone quality. Expanding the tangential contact clearance revealed considerable unrecognized shear risk surrounding the asymmetric cone, while the augmented construct remained insensitive to this parameter in the high-risk range (> 100 μm). Conclusion: Asymmetric cones are viable in good bone stock but exhibit instability in osteoporosis due to the cantilever effect. Anatomical reconstruction with a modular augment and central cone provides a predictable, load-sharing structural column, making it the preferred strategy for large medial defects in osteoporotic patients.

Identifiers

PMID42899483
PMCPMC13682064

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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.