Digital public defence: Jan Egil Brattgjerd Jan Egil Brattgjerd at Institute of Clinical Medicine will be defending the thesis Biomechanics of locking plates in femoral neck fixation for the degree of PhD (Philosophiae Doctor).

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Photo: Amalie Huth Hovland, UiO

The public defence will be held as a video conference over Zoom.

The defence will follow regular procedure as far as possible, hence it will be open to the public and the audience can ask ex auditorio questions when invited to do so.

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Due to copyright reasons, an electronic copy of the thesis must be ordered from the faculty. In order for the faculty to have time to process the order, it must be received by the faculty no later than 2 days prior to the public defence. Orders received later than 2 days before the defence will not be processed. Inquiries regarding the thesis after the public defence must be addressed to the candidate.


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Adjudication committee

  • First opponent: Professor Peter Augat, BG Unfallklinik Murnau, Germany
  • Second opponent: Associate Professor Margareta Hedström, Karolinska Institute, Stockholm, Sweden
  • Third member and chair of the evaluation committee: Professor II Hilde Berner Hammer, Institute of Clinical Medicine, University of Oslo

Chair of defence

Professor II Pål Aksel Næss, Institute of Clinical Medicine, University of Oslo

Principal supervisor

Professor emeritus Harald Steen, Institute of Clinical Medicine, University of Oslo


Jan Egil Brattgjerd MD described the biomechanical stability of femoral neck fracture fixation with special regard to the novel principle of interlocked pins in a plate developed to promote multi-directional stability and healing. Further aims were to analyse if patient safety requirements were met by investigating the novel implant´s strengths and weaknesses.        

A definite biomechanical impact was detected with increased multi-directional stability without adverse effects in comparison with other relevant conventional fixation methods in a comprehensive ex vivo evaluation. As intended during implant design development, the physical effect justified introducing the novel implant into the clinics.            

The profound impact on torsional stability, but also the enhanced bending and compressive stability can be explained by moment of inertia considerations of single beam prisms, where a larger footprint of the bone-implant construct describes the higher resistance to loading. This corresponds with the mechanism of action by interlocked pins to improve load distribution by equal transmission amongst pins from fragile cancellous bone medially in the femoral head to solid cortical bone laterally in the trochanteric area.    

The modestly improved compressive stability from dynamic testing may be indicative of the role of the interlocking plate to allow for a stabilising controlled intermediate compression by impaction of the fragments during loading with such an implant.                     

However, whether the improved gross stability is sufficient to enhance healing conditions or affect failure patterns in vivo, will be the topic of forthcoming clinical trials. So far, the results are promising and the interlocked pins must be considered a favourable development of the pin concept.

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Published Jan. 14, 2021 10:54 AM - Last modified Feb. 1, 2021 10:34 AM