Condition category
Musculoskeletal Diseases
Date applied
Date assigned
Last edited
Prospectively registered
Overall trial status
Recruitment status
No longer recruiting
Publication status

Plain English Summary

Background and study aims
The number of knee replacements taking place in the UK is continuing to rise. Part of the reason for this increase is that knee replacements are increasingly being performed for patients who are older and with other health conditions in addition to their osteoarthritis. It is known that age is not a barrier to having a good outcome from knee replacement, with reports of successful outcome in patients aged over 90 years. However, it is also known that around 15% of patients do not report a good outcome from their knee replacement and have continuing pain and mobility problems that limit or prevent them from being able to do the activities they would like to be able to do after their knee replacement. It is thought that factors such as the amount of pain and limitation of balance and muscle strength may contribute to poorer outcome. Currently it is normal practice for patients to receive a short course (between 4-6 sessions) of post-operative physiotherapy after their surgery. This is usually delivered in a physiotherapy outpatient clinic setting. Previous research has shown that this short course of physiotherapy is not needed by all patients to help them recover after their operation. Given the increasing number of knee replacements, the relatively limited physiotherapy resources available and the increasing age and frailty of patients receiving joint replacements, it is important that we concentrate our rehabilitation resources on those patients who most need help to avoid poor outcome.

Who can participate?
Patients aged 55 or over undergoing knee replacement surgery and deemed to be at risk of poor outcome.

What does the study involve?
First, we will develop a screening tool that will help us to identify those patients who are most at risk of poor outcome after their joint replacement. Second, we will develop and test a rehabilitation exercise intervention designed to improve the function of ‘at risk’ patients and their participation in activities. Patients deemed at risk of poor outcome will be randomly allocated to either the intervention or the control group. Both groups will receive the same treatment whilst in hospital and the same advice about exercise on discharge. Those in the control group will receive standard post-operative care which may include outpatient physiotherapy. Those in the intervention group will receive a home-based exercise programme. We will measure patients’ progress at 6 months and one year after their surgery. We will assess whether this new intervention improves patient’s functional abilities, quality of life and their taking part in social activities. We will use information from diaries kept by patients about their visits to their GP, district nurse, physiotherapy, occupational therapy, any hospital visits and medication and equipment to perform an analysis of the costs and benefits of the new intervention compared to usual care. We will also interview patients, carers and therapists to gain their perspectives about our intervention.

What are the possible benefits and risks of participating?
We do not expect any particular benefits from taking part in the study for individual participants. The information we get from this study will help us to treat future patients with knee replacement. However, it is known that rehabilitation can improve outcomes after knee replacement. There are no new treatments included in this study. The treatments are those already used with patients after knee replacement. There should be no more risk in the community-based rehabilitation group as in standard care.

Where is the study run from?
Nuffield Orthopaedic Centre (UK)

When is the study starting and how long is it expected to run for?
August 2014 to January 2019

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

Who is the main contact?
Karen Barker

Trial website

Contact information



Primary contact

Mrs Karen Barker


Contact details

Nuffield Orthopaedic Centre
Windmill Road
United Kingdom

Additional identifiers

EudraCT number number

Protocol/serial number

HTA 12/196/08

Study information

Scientific title

COmmunity-based Rehabilitation after Knee Arthroplasty (CORKA): a prospective individually randomised two-arm randomised controlled trial



Study hypothesis

Aims and objectives:
1. To analyse data from the KAT study (outcomes in arthroplasty) to develop an algorithm to be used at the pre-operative assessment to identify patients likely to be at risk of poor outcome after knee replacement
2. To develop a treatment intervention that can be delivered in patients' own homes by rehabilitation assistants supervised by qualified therapists
3. To compare the clinical outcomes of this new rehabilitation protocol vs. usual care of outpatient-based post-operative physiotherapy
4. To assess the safety and serious adverse events associated with the treatment programme
5. To assess the acceptability and adherence to the treatment programmes for patients and therapists using a RCT with a nested qualitative study
6. To assess the cost effectiveness of the different treatment strategies

More details can be found at
Protocol can be found at

Ethics approval

NRES Committee South Central Oxford B – provisional opinion given 20/01/2015, ref: 15/SC/0019

Study design

Prospective individually randomised single-blinded two-arm 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 contact details to request a participant information sheet


Knee osteoarthritis


A two-stage study is proposed. Firstly, we will perform analysis of factors associated with poor outcome to develop a screening algorithm. Methods to identify people at high risk are uncertain, but general principles of older people with generalised frailty and significant global function/cognitive impairment prior to surgery are widely accepted. We aim to identify patients at risk of poor outcome using two methods:
1. We will systematically review the literature and use expert opinion from rehabilitation clinicians to identify factors associated with poor outcome after knee arthroplasty.
2. We will examine data from a large study cohort of patients from the KAT study.

In the second stage we will conduct a prospective individually randomised single-blinded two-arm RCT. Patients deemed at risk of poor outcome will be randomised to either the intervention or the control arm. Both arms of the trial will receive the same treatment whilst in hospital and the same advice about exercise on discharge. Those in the normal care arm would receive standard post-operative care which may include outpatient physiotherapy; those in the intervention arm will receive a home-based exercise programme. We will measure patients’ progress at 6 months and one year after their surgery.

Intervention type



Drug names

Primary outcome measure

Late Life Function and Disability Instrument (LLFDI) score, collected at baseline, 6 and 12 months after randomisation. Primary endpoint:12 months post-surgery

Secondary outcome measures

Questionnaires at baseline, 6 months and 12 months:
1. Oxford Knee Score
2. Physical Activity Scale for the Elderly (PASE)
3. EQ-5D-5L
4. Functional Co-morbidities Index

Physical measures at baseline, 6 months and 12 months:
1. Figure of 8 walk test - participants are asked to walk in a figure of 8 around two cones, this is timed, the number of steps taken is counted, in addition to accuracy (if a participant stays with in boundary of the test) being recorded.
2. 30 Second Chair Stand Test - the participant starts sitting on a chair which has a seat high of 17 inches, the participant is asked to complete as many full stands in 30 seconds, the participant sits in between each stand. The number of full stands a person can complete is recorded.
3. Single leg stance - the participant is asked to stand and lift one leg without using any other support, they will be timed standing on one leg. The participant will be stood with a chair in front of them should they require support.

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Participant is willing and able to give informed consent for participation in the study
2. Male or female, aged 55 years or above
3. Primary unilateral KR as a scheduled procedure
4. Deemed by study screening tool developed to be at risk of poor outcome
5. Happy to allow physiotherapy teams to attend their home to deliver the intensive rehabilitation programme if randomised to the intervention arm

Participant type


Age group




Target number of participants


Participant exclusion criteria

1. Any absolute contraindications to exercise
2. Severe cardiovascular or pulmonary disease (New York Heart Association III-IV)
3. Severe dementia, assessed using the hospital dementia screening tool
4. Rheumatoid arthritis
5. Further lower limb arthroplasty surgery planned within 12 months

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

Nuffield Orthopaedic Centre
Windmill Road
United Kingdom

Sponsor information


University of Oxford

Sponsor details

Clinical Trials and Research Governance
Joint Research Office
Block 60
Churchill Road
United Kingdom

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

National government


United Kingdom

Results and Publications

Publication and dissemination plan

To be confirmed at a later date

Intention to publish date


Participant level data

Available on request

Basic results (scientific)

Publication list

1. 2016 protocol in:
2. 2018 statistical analysis plan in:

Publication citations

Additional files

Editorial Notes

21/01/2020: The intention to publish date has been changed from 01/12/2019 to 30/06/2020. 20/01/2020: The overall trial end date has been changed from 01/01/2019 to 31/12/2019. 02/07/2019: The following changes were made to the trial record: 1. The recruitment end date was changed from 31/08/2017 to 01/01/2019. 2. The overall trial end date was changed from 30/06/2018 to 01/01/2019. 3. The intention to publish date was changed from 01/05/2019 to 01/12/2019. 21/11/2018: Publication reference added. 17/10/2016: Publication reference added. 15/08/2016: Changed recruitment end date from 28/02/2017 to 31/08/2017. Changed number of participants from 632 to 635. Added trial website url