Total Or Partial Knee Arthroplasty Trial


Total or Partial Knee Arthroplasty Trial (TOPKAT)

The TOPKAT trial is a multi-centre randomised controlled trial designed to examine the clinical- and cost-effectiveness of total and partial knee replacements for medial compartmental osteoarthritis.

The Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences (NDORMS) at the University of Oxford will co-ordinate the trial in collaboration with the Health Services Research Unit at the University of Aberdeen.  The project is funded by the NIHR Health Technology Assessment Programme. 

HTA project Reference: 08/14/08


In the majority of patients with osteoarthritis of the knee the disease originates in the medial compartment.  There are two different approaches to replacing this arthritic area.  Some surgeons feel that it is always best to replace both the knee compartments with a Total Knee Replacement (TKR).  Others feel it is best to replace just the damaged component of the knee with a Unicompartmental Replacement (UKR).  There is little agreement amongst knee surgeons.  Both interventions are established and well documented procedures, yet little evidence exists to support their practices.  Each intervention is considered standard care but little evidence exists to prove the clinical and cost effectiveness of either management option. 


The aim of TOPKAT will be to assess the clinical and cost effectiveness of Total Knee Replacements versus Unicompartmental Knee Replacements in patients with medial osteoarthritis.                                                                       

Study Participants and Recruitment

Patients will be recruited by their Consultant Knee Surgeon in collaboration with the local research team.  TOPKAT will aim to recruit 500 patients altogether from approximately 20 centres throughout the United Kingdom.  Patient recruitment is over a 2 year period.  Information to be collected and analysed includes:

Patient focused questionnaires regarding knee pain and function;

Patient focused questionnaires regarding the economic cost of the treatment;

Health care resources used (i.e. hospital stays, operating theatre equipment);

Post operative radiological assessments.



The research team in Oxford consist of academic and clinical staff, surgeons, physiotherapists and nurses, with research experience and expertise in Orthopaedics.  Other members of the team include outcome analysists and health economists.   The team is lead by Dr David Beard.The TOPKAT team in Aberdeen consists of statisticians and triallists who have great experience and expertise in running large randomised surgical trials.  The team is lead by Professor Marion Campbell.

For further information please contact Loretta Davies, Trial Coordinator, 01865 737210, email

Health Services Research Unit, University of Aberdeen -