Public Defence: Gunnar Petursson Gunnar Petursson at Institute of Clinical Medicine will be defending the thesis “Computernavigation and fixation in total knee replacements: A registry based and randomized clinical trial study including radiostereometric analysis” for the degree of PhD (Philosophiae Doctor).

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Trial Lecture – time and place

See Trial Lecture.

Adjudication committee

  • First opponent: Överläkare Anders Henricson, Ortopediska kliniken, Falu lasaret
  • Second opponent: Professor Ewa M. Roos, Institut for Idræt og Biomekanik, Det Sundhedsvidenskabelige Fakultet, Syddansk Universitet
  • Third member and chair of the evaluation committee: Professor Ivan Hvid, University of Oslo

Principal Supervisor

Professor Ove Furnes, University of Bergen


Operations with total knee replacements (TKR) in Norway have increased from 995 in 1994 to almost 7000 in 2018. The revision rate (reoperations), the first 10 years, is about 5-10%. Revision is a more difficult operation with higher risk of complication.

About 80% of patients operated with TKR get good clinical results. However, about 20% of the patients still have pain or other symptoms from their knee after TKR.

TKR is a technical demanding operation. Clinical results relies on right positioning of the implants in relation to the skeletal bone and right balancing of ligaments. Good fixation is important to, to minimise loosening of the implant when used.

Computer-navigation has been used to improve positioning of the implant. However, it is still debatable whether this leads to better clinical outcomes.

Despite a lack of documentation, has the use of hybrid fixation, with cemented tibia and uncemented femur, increased in Norway.

In this PhD – Computer navigation and fixation in total knee replacements: A registry based and randomised clinical trial study including radiostereometric analysis (RSA), Gunnar Petursson and colleges have studied the importance of computer-navigation and hybrid fixation on TKR.

They used a double-blinded randomised clinical trial, to compere computer-navigation to standard method; evaluating clinical outcome, using patient related clinical outcome scores (PROMs) and clinical evaluation by physiotherapists. RSA was used to evaluate the risk of prosthesis loosening. The main conclusion was that patients operated with computer-navigation had a better clinical outcome.

Survival analysis of data from the Norwegian Arthroplasty Register showed that TKR operated with hybrid fixation had a lower risk of revision than cemented TKR.

Gunnar Petursson hope that this PhD will help to make TKR safer for the general patient.

Additional information

Contact the research support staff.

Published Aug. 19, 2019 4:30 PM - Last modified Aug. 22, 2019 4:59 PM