The aim of the study was to simulate the effects, ulnar variance has on the load distribution to the radius and ulna during maximal gripping and compare to previously published measurements, which used load cells placed on the forearm bones to measure the load ratio

Bransby-Zachary, Marc

Gislason, M.K.

Hems, Tim

Nash, D.H.

Stansfield, B.W.

English

Name not available

Ulnar variance and load transfer in the forearm during maximal grip: a finite element study

University of Strathclyde Institutional Repository

Strathprints Institutional RepositoryGislason, M.K. and Stansfield, B.W. and Nash, D.H. and Hems, Tim and Bransby-Zachary, Marc(2009) Ulnar variance and load transfer in the forearm during maximal grip: a finite element study.In: Combined Scientific Meeting of the British and American Societies of Surgery of the Hand,2009-04-30 - 2009-05-02, London, UK.Strathprints is designed to allow users to access the research output of the University of Strathclyde.Copyright c© and Moral Rights for the papers on this site are retained by the individual authorsand/or other copyright owners. You may not engage in further distribution of the material for anyprofitmaking activities or any commercial gain. You may freely distribute both the url (http://strathprints.strath.ac.uk/) and the content of this paper for research or study, educational, ornot-for-profit purposes without prior permission or charge.Any correspondence concerning this service should be sent to Strathprints administrator:mailto:strathprints@strath.ac.ukhttp://strathprints.strath.ac.uk/  Gislason, M.K. and Stansfield, B.W. and Nash, D.H. and Hems, T. and Bransby-Zachary, M. (2009) Ulnar variance and load transfer in the forearm during maximal grip: a finite element study. In: Combined Scientific Meeting of the British and American Societies of Surgery of the Hand, 30 April - 2 May 2009, London, UK.   http://strathprints.strath.ac.uk/20173/  This is an author produced version of a paper published in Combined Scientific Meeting of the British and American Societies of Surgery of the Hand, 30 April - 2 May 2009, London, UK. This version has been peer-reviewed but does not include the final publisher proof corrections, published layout or pagination.   Strathprints is designed to allow users to access the research output of the University of Strathclyde. Copyright © and Moral Rights for the papers on this site are retained by the individual authors and/or other copyright owners. You may not engage in further distribution of the material for any profitmaking activities or any commercial gain. You may freely distribute both the url (http://strathprints.strath.ac.uk) and the content of this paper for research or study, educational, or not-for-profit purposes without prior permission or charge. You may freely distribute the url (http://strathprints.strath.ac.uk) of the Strathprints website.  Any correspondence concerning this service should be sent to The Strathprints Administrator: eprints@cis.strath.ac.uk  Ulnar variance and load transfer in the forearm during maximum grip: A finite element study    Magnús K. Gíslason1*, David H. Nash1,  Marc Bransby-Zachary2, Tim Hems3,  Benedict Stansfield4 1Bioengineering Unit, Wolfson Building, University of Strathclyde, 106 Rottenrow, Glasgow, G4 0NW, UK, 2Southern General Hospital, Glasgow, UK, 3Victoria Royal Infirmary, Glasgow, UK, 4Glasgow Caledonian University, Glasgow, UK  Introduction/Aims The aim of the study was to simulate the effects, ulnar variance has on the load distribution to the radius and ulna during maximal gripping and compare to previously published measurements, which used load cells placed on the forearm bones to measure the load ratio.    Material/Methods Three finite element models were created of the whole wrist, including the distal end of the radius and ulna, 7 carpal bones (pisiform was omitted from the study) and the proximal third of the metacarpals. The finite element model was geometrically based on 3T MRI scans with resolution of 230x230 µm in plane resolution and with 700 µm slice thickness. The scans were digitised using Mimics software where three dimensional objects were created of the bones and meshed. The structure was assembled in Abaqus v.6.7 where the modelling was carried out. Subject specific loading conditions were applied to the metacarpals, where the subjects carried out grip strength measurements where the measured forces were converted into contact joint forces using a biomechanical model.  Results/Statistics The load transfer percentage was calculated for the natural ulnar variance of each subject. The ulna was then moved 4.5mm in proximal and distal direction simulating negative variance and positive variance. The results are summarized in Table 1.  Subject 1 [%] Subject 2 [%] Subject 3 [%] Cadaveric study [%] Variance Radius Ulna Radius Ulna Radius Ulna Radius Ulna - var 92.6 7.4 93.8 6.2 88.8 12.2 95.7 4.3 0 91.1 8.9 92.8 7.2 78.7 21.3 81.6 18.4 + var 54.0 46.0 89.0 11.0 63.5 36.5 58.1 41.9 Table 1: The  effect of positive and negative ulnar variance on forearm load transfer     Conclusions/Clinical Reference From the results it can be seen a dramatic increase in the load transfer through the ulna for the positive variance simulation for two of the three subjects. The results are in coherence with the findings of Palmer and Werner (1984). 

From the results it can be seen a dramatic increase in the load transfer through the ulna for the positive variance simulation for two of the three subjects. The results are in coherence with the findings of Palmer and Werner

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Ulnar variance and load transfer in the forearm during maximal grip: a finite element study

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