A randomised controlled trial of different knee prostheses

ISRCTN ISRCTN45837371
DOI https://doi.org/10.1186/ISRCTN45837371
Secondary identifying numbers HTA 95/10/01
Submission date
25/04/2003
Registration date
25/04/2003
Last edited
08/08/2023
Recruitment status
No longer recruiting
Overall study status
Completed
Condition category
Musculoskeletal Diseases
Prospectively registered
Protocol
Statistical analysis plan
Results
Individual participant data

Plain English summary of protocol

Background and study aims
In knee replacement surgery (knee arthroplasty), all or part of a damaged knee joint is replaced with metal and/or plastic components. Various approaches to knee replacement surgery are used and different designs are available. It was not clear which works better or is safer. The aim of this study is therefore to answer three questions. Should the back surface of the knee cap routinely be resurfaced with an additional plastic part? Should the metal and plastic parts of the knee replacement be firmly fixed together (fixed bearing), or should the plastic part be mobile to allow more normal knee movement (mobile bearing)? Should the part of the knee replacement that attaches to the shin bone (the tibial component), be all plastic or plastic with a metal backing?

Who can participate?
Patients undergoing knee replacement surgery

What does the study involve?
Participants can take part in one or two of the four study comparisons depending on the extent and type of disease in their knee. In each comparison participants are randomly allocated to one of two knee operations (i.e., knee cap resurfacing or no resurfacing; fixed bearing or mobile bearing; all plastic or plastic-and-metal tibial component; partial or total knee replacement). All participants are asked to complete postal questionnaires after three months and annually thereafter up to 20 years after the surgery. The postal questionnaires ask about knee function, general quality of life and healthcare costs. Information is also collected about any complications and further hospital admissions and operations.

What are the possible benefits and risks of participating?
Participants may not benefit personally from taking part in the study but they will be helping doctors to assess which operations are best and safest. We do not think there are any additional risks or disadvantages to participants. Whichever group they are allocated, their operation will be performed by an experienced orthopaedic surgeon. Steps are always taken to make sure that any possible risks are minimised. As part of routine care, participants will be well informed of potential risks.

Where is the study run from?
University of Oxford (UK)

When is the study starting and how long is it expected to run for?
December 1998 to June 2023

Who is funding the study?
Health Technology Assessment Programme (UK)

Who is the main contact?
Prof. David Murray, david.murray@ndorms.ox.ac.uk

Contact information

Prof David Murray
Scientific

NDORMS
Botnar Research Centre
Nuffield Orthopaedic Centre
Headington
Oxford
OX3 7LD
United Kingdom

ORCiD logoORCID ID 0000-0002-0839-3166
Phone +44 (0)1865 227457
Email david.murray@ndorms.ox.ac.uk
Dr Suzanne Breeman
Scientific

University of Aberdeen
Health Services Research Unit
Health Sciences Building
Foresterhill
Aberdeen
AB25 2ZD
United Kingdom

Email s.breeman@abdn.ac.uk

Study information

Study designRandomised controlled trial
Primary study designInterventional
Secondary study designRandomised controlled trial
Study setting(s)Hospital
Study typeTreatment
Participant information sheet Not available in web format, please use the contact details below to request a patient information sheet
Scientific titleA randomised controlled trial of different knee prostheses
Study acronymKAT (Knee Arthroplasty Trial)
Study objectivesA UK wide network of clinical centres will be established to conduct randomised partial factorial trials on current practice of knee replacement. Independent management by health services research units is a feature of the application. Individual surgeons will be invited to consider areas of uncertainty concerning current knee prosthetic and participate in randomisation between certain design aspects of knee replacement systems which are otherwise similar in all other respects.
The project will require two phases, each of six years. At end of first phase, the trial will demonstrate short to medium-term variations in costs and outcome relating to the four management options. The second phase is necessary in order to demonstrate prosthesis design-related adverse events. This trial will produce authoritative data to inform purchasers, providers, consumers and clinicians about this very commonly performed procedure in the NHS.

More details can be found at:
1. http://www.nets.nihr.ac.uk/projects/hta/951001
2. http://w3.abdn.ac.uk/HSRU/CHART/public/trials/TrialDetails.aspx?page=current-trials&tid=15

Protocol can be found at: http://www.nets.nihr.ac.uk/__data/assets/pdf_file/0003/53724/PRO-95-10-01.pdf
Ethics approval(s)Multi-centre Research Ethics Committee for Scotland, 30/11/1998, ref: MREC/98/0/100
Health condition(s) or problem(s) studiedPrimary knee replacement surgery
InterventionCurrent interventions as of 23/01/2009:
The trial is evaluating four aspects of knee replacements:
1. Metal backing of the tibial component compared with a single high density polyethylene component (350 participants)
2. Patellar resurfacing compared with no resurfacing (1400 participants)
3. A polyethylene mobile bearing component between the tibia and femur compared with a fixed bearing arthroplasty (350 participants)
4. Uni-compartmental arthroplasty compared with total knee replacement (350 participants)

Individual patients can participate in a maximum of two comparisons and then only if the surgeon responsible for care is substantially uncertain about these particular aspects.

Previous interventions:
The four management options are:
1. Metal versus non-metal backing of the tibial component
2. Whether to resurface the patella
3. Unicompartmental versus total knee arthroplasty
4. Mobile versus fixed bearing
Intervention typeProcedure/Surgery
Primary outcome measureCurrent primary outcome measures as of 23/01/2009:
Oxford Knee Score (postal questionnaire) at 3 months and then annually thereafter.

Previous primary outcome measures:
Outcomes will be in terms of complications and patient-assessed pain and function, principally conducted by post.
Costings include those relating to
1. Early complications expected immediately post operatively from medical effects
2. Medium-term complications such as dislocation and infection
3. Late complications of wear, loosening and infection.
Secondary outcome measuresAdded as of 23/01/2009:
Complications and patient-assessed pain and function, assessed principally by postal questionnaires including:
1. SF-12
2. EQ-5D
3. Questions about any further hospital admissions and surgery
4. Costings:
4.1. Early complications expected immediately post-operatively from medical effects
4.2. Medium-term complications such as dislocation and infection
4.3. Late complications of wear, loosening and infection

Questionnaires are completed at 3 months and then annually thereafter.
Overall study start date31/12/1998
Completion date30/06/2023

Eligibility

Participant type(s)Patient
Age groupOther
SexBoth
Target number of participants2,450
Key inclusion criteriaAdded as of 23/01/2009:
1. A decision has been made to have primary knee replacement surgery
2. The surgeon has no clear preference for a specific option in at least one of the comparisons
3. Both males ane females, no age limits
Key exclusion criteriaDoes not meet inclusion criteria
Date of first enrolment01/07/1999
Date of final enrolment31/12/2002

Locations

Countries of recruitment

  • England
  • Scotland
  • United Kingdom

Study participating centres

University of Oxford
Oxford
OX3 7LD
United Kingdom
University of Aberdeen
Health Services Research Unit
Aberdeen
AB25 2ZD
United Kingdom

Sponsor information

Department of Health (UK)
Government

Quarry House
Quarry Hill
Leeds
LS2 7UE
United Kingdom

Email Sheila.Greener@doh.gsi.gov.uk
Website http://www.dh.gov.uk/en/index.htm

Funders

Funder type

Government

Health Technology Assessment Programme
Government organisation / National government
Alternative name(s)
NIHR Health Technology Assessment Programme, HTA
Location
United Kingdom

Results and Publications

Intention to publish date
Individual participant data (IPD) Intention to shareYes
IPD sharing plan summaryAvailable on request
Publication and dissemination planTo be confirmed at a later date
IPD sharing plan

Study outputs

Output type Details Date created Date added Peer reviewed? Patient-facing?
Results article Baseline characteristics, and 2-year functional outcomes 01/01/2009 Yes No
Results article cost-effectiveness analysis results 30/01/2012 Yes No
Results article Clinical effectiveness and cost-effectiveness after a median of 10 years follow-up 01/03/2014 Yes No

Editorial Notes

08/08/2023: One of the scientific contact's details has been updated.
31/05/2016: the overall trial end date was changed from 31/12/2010 to 30/06/2023.
27/02/2009: Please note that an incorrect target number of participants was entered in this trial record at time of registration. Therefore, the number (413 participants) has been amended to the correct number (approximately 2,450).