Evidence map›Paper›PMID 42393746›Full record

ArticleArthroplasty (London, England)2026

Biomechanical effects of varus stem alignment on a cementless metadiaphyseal anchoring hip stem: a biomechanical investigation.

Philipp Kastner, Matthias Luger, Moritz Kraus, Ivan Zderic, Boyko Gueorguiev, Tobias Gotterbarm, Clemens Schopper

Abstract read
In one paragraph

Article in Arthroplasty (London, England), 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

What it found

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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

7 authors.

Philipp Kastner *Department for Orthopaedics and Traumatology, Kepler University Hospital GmbH, Johannes Kepler University Linz, Krankenhausstrasse 9, Altenberger Strasse 69, 4040, Linz, Austria.
Matthias Luger *Department for Orthopaedics and Traumatology, Kepler University Hospital GmbH, Johannes Kepler University Linz, Krankenhausstrasse 9, Altenberger Strasse 69, 4040, Linz, Austria.
Moritz Kraus *AO Research Institute Davos, Clavadelerstrasse 8, 7270, Davos, Switzerland. moritz.kraus@usz.ch.
Ivan ZdericAO Research Institute Davos, Clavadelerstrasse 8, 7270, Davos, Switzerland.
Boyko GueorguievAO Research Institute Davos, Clavadelerstrasse 8, 7270, Davos, Switzerland.
Tobias GotterbarmDepartment for Orthopaedics and Traumatology, Kepler University Hospital GmbH, Johannes Kepler University Linz, Krankenhausstrasse 9, Altenberger Strasse 69, 4040, Linz, Austria.
Clemens SchopperDepartment for Orthopaedics and Traumatology, Kepler University Hospital GmbH, Johannes Kepler University Linz, Krankenhausstrasse 9, Altenberger Strasse 69, 4040, Linz, Austria.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundMinimally invasive surgical approaches have become standard in cementless hip arthroplasty; however, the recent literature still lacks biomechanical evidence regarding the effects of stem malpositioning. This study aimed to biomechanically evaluate the stability of a cementless metadiaphyseal anchoring stem implanted with a varus malposition versus a neutral alignment.

methodsTwenty paired human cadaveric femora were assigned pairwise for stem implantation featuring either 8° varus malposition (Group 1) or neutral orientation (Group 2). All specimens underwent quasi-static testing and progressively increasing cyclic loading to failure with monitoring via motion tracking.

resultsAxial stiffness in Group 1 was significantly lower than in Group 2, p = 0.023. Implant size in Group 1 was significantly smaller than that in Group 2, p = 0.002. Load at 0.15 mm stem subsidence and cycles to 0.15 mm subsidence in Group 1 were not significantly different compared to Group 2, p = 0.214. Load at 1 mm subsidence and cycles to 1 mm subsidence in Group 1 were significantly higher than those in Group 2, p = 0.022.

conclusionAn 8° varus-aligned cementless metadiaphyseal anchoring hip stem demonstrates superior load-bearing capacity with higher loads and numbers of cycles until reaching defined subsidence thresholds under dynamic loading, as compared to neutral alignment. These results demonstrate the biomechanical tolerance of unintended intraoperative varus malalignment, but do not support or recommend intentional varus stem positioning.

Indexed as

Axial stabilityBiomechanical cadaveric testingCementless hip stemVarus malposition

Identifiers

PMID42393746
PMCPMC13330087

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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.