Open Access Research article

An economic model to evaluate cost-effectiveness of computer assisted knee replacement surgery in Norway

Øystein Gøthesen1*, James Slover2, Leif Havelin34, Jan Erik Askildsen5, Henrik Malchau6 and Ove Furnes34

Author Affiliations

1 Department of Orthopaedic Surgery, Haugesund Hospital, Karmsundsgate 120, 5528, Haugesund, Norway

2 Department of Orthopaedic Surgery, New York University (NYU) Hospital for Joint Diseases, 301 East 17th Street; Suite 1616, New York, NY 10003, USA

3 The Norwegian Arthroplasty Register, Department of Orthopedic Surgery, Haukeland University Hospital, Jonas Lies vei 65, 5053, Bergen, Norway

4 Department of Surgical Sciences, University of Bergen, 5021, Bergen,Norway

5 Stein Rokkan Centre for Social Studies, Uni Research, University of Bergen, 5021, Bergen, Norway

6 Department of Orthopaedic Surgery, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, USA

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BMC Musculoskeletal Disorders 2013, 14:202  doi:10.1186/1471-2474-14-202

Published: 6 July 2013



The use of Computer Assisted Surgery (CAS) for knee replacements is intended to improve the alignment of knee prostheses in order to reduce the number of revision operations. Is the cost effectiveness of computer assisted surgery influenced by patient volume and age?


By employing a Markov model, we analysed the cost effectiveness of computer assisted surgery versus conventional arthroplasty with respect to implant survival and operation volume in two theoretical Norwegian age cohorts. We obtained mortality and hospital cost data over a 20-year period from Norwegian registers. We presumed that the cost of an intervention would need to be below NOK 500,000 per QALY (Quality Adjusted Life Year) gained, to be considered cost effective.


The added cost of computer assisted surgery, provided this has no impact on implant survival, is NOK 1037 and NOK 1414 respectively for 60 and 75-year-olds per quality-adjusted life year at a volume of 25 prostheses per year, and NOK 128 and NOK 175 respectively at a volume of 250 prostheses per year. Sensitivity analyses showed that the 10-year implant survival in cohort 1 needs to rise from 89.8% to 90.6% at 25 prostheses per year, and from 89.8 to 89.9% at 250 prostheses per year for computer assisted surgery to be considered cost effective. In cohort 2, the required improvement is a rise from 95.1% to 95.4% at 25 prostheses per year, and from 95.10% to 95.14% at 250 prostheses per year.


The cost of using computer navigation for total knee replacements may be acceptable for 60-year-old as well as 75-year-old patients if the technique increases the implant survival rate just marginally, and the department has a high operation volume. A low volume department might not achieve cost-effectiveness unless computer navigation has a more significant impact on implant survival, thus may defer the investments until such data are available.

Artrhroplasty; Computer navigation; Cost-effectiveness; Health economy; Register; Markov