What are the treatments and outcomes of people with obesity and severe knee osteoarthritis?
| ISRCTN | ISRCTN42984928 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN42984928 |
| IRAS number | 341128 |
| Secondary identifying numbers | CPMS 64836 |
- Submission date
- 07/10/2024
- Registration date
- 29/10/2024
- Last edited
- 10/07/2025
- Recruitment status
- Recruiting
- Overall study status
- Ongoing
- Condition category
- Musculoskeletal Diseases
Plain English summary of protocol
Background and study aims
In the UK, nearly 18.5 million people live with obesity, making them almost five times more likely to develop knee arthritis compared to those with normal weight. Severe knee arthritis can be treated with a knee replacement, but many areas in the UK have rules that prevent obese people from having this surgery. This study aims to understand how best to help people with obesity and severe knee arthritis, whether they can have surgery or not. It will look at current treatments, how well they work for knee pain, and the relationship between weight, body image, and knee pain.
Who can participate?
Adults with severe knee arthritis of any weight who have good enough English language skills to respond to questionnaires can participate.
What does the study involve?
1. Interview study: Participants will answer questions about their feelings regarding the care they receive for knee arthritis and their weight. The researcher will identify common themes from these interviews to understand what people think about NHS treatments for arthritis and obesity.
2. Cohort study: 210 people with obesity will be asked to participate from three hospitals. They will answer questions about knee pain, disability, and body image at their appointment or at home. They will be contacted again 6 and 12 months later to update on their weight, treatments received, any surgeries, knee pain, and quality of life. This will help identify which factors most strongly impact knee pain.
3. Measurement of key patterns: 190 more people of any weight with severe arthritis will fill in surveys at one time point. These surveys will measure knee pain, disability, and body image. The answers will be analyzed to find patterns and connections between knee pain, body image, and care experiences.
What are the possible benefits and risks of participating?
There are no specific benefits to taking part, but participants will help improve knowledge about the links between psychosocial factors and knee pain, aiding future patient care and research. There are no additional physical risks as the study does not change or influence treatment pathways.
Where is the study run from?
The study is run from Warwick Clinical Trials Unit, Warwick Medical School, University of Warwick, Coventry, UK.
When is the study starting and how long is it expected to run for?
February 2024 to December 2027
Who is funding the study?
The study is funded by the National Institute for Health and Care Research (NIHR; UK)
Who is the main contact?
Dr Fatema Dhaif, Orthopaedic Registrar and Doctoral Research Fellow, University of Warwick (OAKS@warwick.ac.uk).
Contact information
Principal Investigator
Warwick Clinical Trials Unit
Warwick Medical School
University of Warwick
Coventry
CV4 7AL
United Kingdom
 ORCID ID |
0000-0002-4515-8202 |
|---|---|
| Phone | +44 (0)24 76575288 |
| a.metcalfe@warwick.ac.uk |
Public, Scientific
Clinical Sciences Research Laboratory
Clinical Sciences Building
Clifford Bridge Road
Coventry
CV2 2DX
United Kingdom
| ORCID ID |
0000-0001-8473-9045 |
|---|---|
| Phone | +44 2476963587 |
| fatema.dhaif@warwick.ac.uk |
Study information
| Study design | Observational study with combined cross-sectional and cohort design with a nested qualitative study |
|---|---|
| Primary study design | Observational |
| Secondary study design | Cohort, cross-sectional, and qualitative |
| Study setting(s) | Hospital |
| Study type | Other |
| Participant information sheet | Not available in web format, please use contact details to request a participant information sheet |
| Scientific title | Obesity and arthritis of the knee study |
| Study acronym | OAKS |
| Study objectives | A trial of an effective weight loss programme is needed for people with obesity and severe osteoarthritis (OA) but important preparatory work is required before this can be performed. The key questions that need to be addressed are a more detailed understanding of the baseline characteristics of people who present with this problem, the treatments that people who attend NHS clinics currently receive both for their weight and their knee problems, the factors that influence pain in this population and the relationship between psychosocial aspects and outcomes scores. Once we understand the answers to these questions, we will be able to select the best interventions and study design for a multi-centre randomised trial to determine the best management for this under-served population. |
| Ethics approval(s) |
Approved 10/10/2024, West of Scotland REC 5 (Ward 11, Dykebar Hospital, Grahamston Road, Paisley, PA2 7DE, United Kingdom; +44 (0)141 314 0213; ggc.wosrec5@nhs.sco), ref: 24/WS/0146 |
| Health condition(s) or problem(s) studied | Knee osteoarthritis |
| Intervention | Qualitative interview study: We will recruit approximately 12 participants with obesity and severe knee arthritis using a purposive sampling technique. Attainment of data saturation will inform the exact sample size. We will perform semi-structured interviews revolving around experience of care and preferences in treatment modalities. Interviews will be recorded, transcribed, and analysed using thematic analysis. The interviews will take place over video teleconference or in person as per participant preference. Prospective cohort study: We will recruit 210 participants with BMI ≥35 from UK secondary care centres. We will collect patient reported outcome measures (PROMs) questionnaire data and BMI from participants at 4 timepoints: baseline, 6, 12, and 24 months. We will also collect data on weight loss treatments delivered and whether participants underwent knee surgery. Follow up questionnaires will be administered over telephone, post or email as per participant preference. |
| Intervention type | Other |
| Primary outcome measure | Oxford Knee Score at 12 months |
| Secondary outcome measures | Recorded at baseline, 12 months and 24 months: 1. Height and weight, which will be used to calculate BMI. This will be measured and recorded by a member of the research team. 2. OKS-APQ (activity participation score) a PROM which was developed as an adjunct to the OKS. The purpose of the APQ is to combat the issue with ceiling effect of the OKS when used alone. 3. Body-Q, a PROM which was developed for use by people with obesity undergoing weight loss interventions. It measures four domains (appearance, eating-related concerns, health-related quality of life and experience of care). An international multi-disciplinary consensus meeting identified which constructs were most important to measure and identified BODY-Q as the PROM instrument which best measured 6 out of 8 of the most important domains. Furthermore, a systematic review of the most suitable instrument for bariatric surgery identified BODY-Q as the instrument with the strongest evidence for content validity. 4. Euro-Qol-5D-5L (EQ-5D-5L) as a measure of health-related quality of life. It is a score assessing mobility, self-care, usual activities, pain/discomfort, and anxiety/depression (5 dimensions). 5. Generalised self-efficacy (GSE) scale 6. Hospital Anxiety and Depression Scale (HADS) |
| Overall study start date | 07/02/2024 |
| Completion date | 31/12/2027 |
Eligibility
| Participant type(s) | Patient |
|---|---|
| Age group | Adult |
| Lower age limit | 18 Years |
| Sex | Both |
| Target number of participants | 400 |
| Key inclusion criteria | For the cohort study: 1. Referral from primary care to secondary or intermediate care services for their knee. 2. Severe arthritis as assessed by the treating clinician which can be defined as KL grade 4 primary knee arthritis (severe) in any knee compartment on a knee radiograph (x-ray) OR clinician deems arthritis severe enough to warrant a TKR. 3. BMI ≥35 kg/m² 4. Aged over 18 years 5. Has capacity to consent to being in a research study 6. Sufficient English language skills to understand study materials and respond to questionnaires For the qualitative study with patients: As above For the cross-sectional study: 1. Any BMI 2. KL grade 4 primary knee arthritis (severe) in any knee compartment |
| Key exclusion criteria | 1. Presence of inflammatory arthritis 2. History of intra-articular fracture causing post-traumatic arthritis 3. Previous surgery on the ipsilateral knee only an exclusion criteria if implants were inserted 4. Unable or unwilling to comply with follow up procedure 5. Unable to provide informed consent (e.g does not have capacity to consent) 6. Insufficient English language skills to understand study materials and respond to questionnaires |
| Date of first enrolment | 01/12/2024 |
| Date of final enrolment | 31/12/2025 |
Locations
Countries of recruitment
- England
- United Kingdom
Study participating centres
Clifford Bridge Road
Coventry
CV2 2DX
United Kingdom
Rake Lane
North Shields
NE29 8NH
United Kingdom
Mindelsohn Way
Edgbaston
Birmingham
B15 2GW
United Kingdom
Eaglestone
Milton Keynes
MK6 5LD
United Kingdom
Luton
LU4 0DZ
United Kingdom
Royal Albert Edward Infirmary
Wigan Lane
Wigan
WN1 2NN
United Kingdom
Marton Road
Middlesbrough
TS4 3BW
United Kingdom
Harlow
CM20 1QX
United Kingdom
Sponsor information
University/education
University of Warwick, Coventry
Coventry
CV4 7AL
England
United Kingdom
| Phone | +44 24 765 75732 |
|---|---|
| sponsorship@warwick.ac.uk | |
| Website | http://www2.warwick.ac.uk/ |
"ROR" |
https://ror.org/01a77tt86 |
Funders
Funder type
Government
Government organisation / National government
- Alternative name(s)
- National Institute for Health Research, NIHR Research, NIHRresearch, NIHR - National Institute for Health Research, NIHR (The National Institute for Health and Care Research), NIHR
- Location
- United Kingdom
Results and Publications
| Intention to publish date | 01/08/2027 |
|---|---|
| Individual participant data (IPD) Intention to share | Yes |
| IPD sharing plan summary | Available on request |
| Publication and dissemination plan | Planned publication in a peer-reviewed journal and presentation at orthopaedic conferences. |
| IPD sharing plan | The datasets generated and/or analysed during the current study will be available upon request from OAKS@warwick.ac.uk |
Editorial Notes
10/07/2025: The following changes were made to the study record:
1. The date of final enrolment was changed from 01/12/2025 to 31/12/2025.
2. The completion date was changed from 01/12/2027 to 31/12/2027.
3. The study participating centres were updated to remove Nottingham University Hospitals NHS Trust and Frimley Health NHS Foundation Trust, and add Milton Keynes University Hospital, Luton & Dunstable University Hospital, Wrightington, Wigan and Leigh Teaching Hospitals NHS Foundation Trust, South Tees Hospitals NHS Foundation Trust and Princess Alexandra Hospital NHS Foundation Trust.
06/12/2024: Ethics approval details added.
21/11/2024: The following changes were made to the study record:
1. The recruitment start date was changed from 01/11/2024 to 01/12/2024.
2. The recruitment end date was changed from 01/11/2024 to 01/12/2025.
3. The overall study end date was changed from 01/11/2025 to 01/12/2027.
06/11/2024: Internal review.
07/10/2024: Trial's existence confirmed by West of Scotland REC 5.
