Condition category
Musculoskeletal Diseases
Date applied
Date assigned
Last edited
Prospectively registered
Overall trial status
Recruitment status

Plain English Summary

Background and study aims
Osteoarthritis is a condition that causes the joints to become painful and stiff. Osteoarthritis of the knee affects a large proportion of the population and this is set to increase over time. Quite often the arthritis is limited to one area of the joint, particularly the inside of the joint. Patients can either have a partial knee replacement or a total knee replacement. The partial knee replacement, as its name suggests, involves the removal and replacement of only the diseased part of the joint. Total knee replacement involves the removal and replacement of the entire knee joint. Total knee replacement is easier to do and considered more reliable (lower failure/revision rate), but it involves cutting away healthy parts of the joint. Partial knee replacement retains healthy tissue and usually achieves better functional results, but is more difficult to do and can have an increased failure/revision rate. There are also significant cost advantages for the healthcare system for partial knee replacements. Unfortunately we currently do not know which type of replacement is best for these particular patients. Hence, the aim of this study is to directly compare the clinical and cost-effectiveness of total knee replacements versus partial knee replacements for patients with osteoarthritis.

Who can participate?
Patients aged 40 or over with osteoarthritis

What does the study involve?
The study is carried out at the local hospital where the patient would normally have their knee replacement. Patients recruited to the study are randomly allocated to undergo either total or partial knee replacement surgery. Patients are then followed up for 10 years after the surgery. The measurements taken to assess which type of knee replacement is better are predominantly patient based. This means that the measurements directly assess how the patient, rather than the surgeon, feels about the outcome after their operation.

What are the possible benefits and risks of participating?
Not provided at time of registration

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

When is the study starting and how long is it expected to run for?
November 2009 to October 2016

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

Who is the main contact?
Dr David Beard

Trial website

Contact information



Primary contact

Dr David Beard


Contact details

Nuffield Department of Orthopaedic
Rheumatology & Musculoskeletal Sciences
Windmill Road
United Kingdom
+44 (0)1865 227695

Additional identifiers

EudraCT number number


Protocol/serial number

HTA 08/14/08; Version 1

Study information

Scientific title

Clinical and cost-effectiveness of total knee replacements versus partial knee replacements for patients with medial compartment osteoarthritis: a multicentre randomised controlled trial



Study hypothesis

To assess the clinical and cost-effectiveness of total knee replacements versus partial knee replacements for patients with medial compartment osteoarthritis.

More details can be found at:
Protocol can be found at:

Ethics approval

Oxfordshire REC C, 04/09/2009, ref: 09/H606/88

Study design

Multicentre prospective superiority randomised controlled trial

Primary study design


Secondary study design

Randomised controlled trial

Trial setting


Trial type


Patient information sheet

Not available in web format, please use the contact details below to request a patient information sheet


Osteoarthritis/avascular necrosis


Total knee replacement surgery versus unicompartmental knee replacement surgery. Patients will be followed up for 10 years post surgery. Going on the average waiting list times of 3 months, the approximate involvement in the study for each participant (recruitment, treatment and follow up) would be 10 years and 3 months.

Intervention type



Drug names

Primary outcome measures

Oxford Knee Score: a patient based validated and effective measure of change over time questionnaire. Both the absolute and the change scores will be analysed at 5- and 10-year points post-operation.

Secondary outcome measures

1. American Knee Society Score: to measure the range of motion and function of the knee, measured at 2 months, 1, 5 and 10 years post-surgery
2. UCLA Activity Score: to measure how active the patient is, measured at 2 months, 1, 5 and 10 years post-surgery
3. X-ray to check for immediate problems, assess the outcome of surgery, complications and make long-term predictions, measured at 2 months, 1, 5 and 10 years post-surgery
4. EQ-5D: to provide data for the economic evaluation, measured at 2 months, 1, 2, 3, 4, 5, 7 and 10 years post-surgery
5. Lund Score: to measure patient satisfaction, measured at 2 months, 1, 2, 3, 4, 5, 7 and 10 years post-surgery
6. Other outcomes, e.g., kinematic and gait assessments, measured at 2 months, 1, 5 and 10 years post-surgery

Overall trial start date


Overall trial end date


Reason abandoned


Participant inclusion criteria

1. Medial osteoarthritis with exposed bone on both femur and tibia or avascular necrosis
2. Functionally intact anterior cruciate ligament (superficial damage or splitting is acceptable)
3. Full thickness lateral cartilage
4. Correctable intra-articular varus deformity (suggestive of functionally intact medical cruciate ligament)
5. Medically fit showing an American Society of Anaesthesiologists (ASA) grade 1 or 2
6. Expectancy of over 10 years of active life
7. Aged 40 years or over, either sex

Participant type


Age group




Target number of participants


Participant exclusion criteria

1. Require revision knee replacement surgery
2. Have rheumatoid arthritis or other inflammatory disorders
3. Are likely to benefit from a specific prosthesis type
4. Are unlikely to be able to perform required clinical assessment tasks
5. Have symptomatic foot, hip or spinal pathology

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

Nuffield Department of Orthopaedic, Rheumatology & Musculoskeletal Sciences
United Kingdom

Sponsor information


University of Oxford (UK)

Sponsor details

Clinical Trials and Research Governance Unit
Manor House
John Radcliffe Hospital
United Kingdom
+44 (0)1865 743002

Sponsor type




Funder type


Funder name

Health Technology Assessment Programme

Alternative name(s)

NIHR Health Technology Assessment Programme, HTA

Funding Body Type

government organisation

Funding Body Subtype

Federal/National Government


United Kingdom

Results and Publications

Publication and dissemination plan

Not provided at time of registration

Intention to publish date

Participant level data

Not provided at time of registration

Results - basic reporting

Publication summary

2013 protocol in:

Publication citations

  1. Protocol

    Beard D, Price A, Cook J, Fitzpatrick R, Carr A, Campbell M, Doll H, Campbell H, Arden N, Cooper C, Davies L, Murray D, Total or Partial Knee Arthroplasty Trial - TOPKAT: study protocol for a randomised controlled trial., Trials, 2013, 14, 292, doi: 10.1186/1745-6215-14-292.

Additional files

Editorial Notes

04/03/2016: Plain English summary added. On 17/09/2009 the overall trial start and end dates were changed from 01/06/2009 and 01/06/2023 to 01/11/2009 and 31/10/2016, respectively.