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 leading cause of pain and disability. Osteoarthritis is when something goes wrong with the repair processes in a joint and this is particularly common in knee joints. Osteoarthritis can lead to changes in a joint including changes in the bone, cartilage, soft tissues and nervous system. Many people with severe knee pain because of osteoarthritis have an operation called total knee replacement. Total knee replacement involves replacing the painful knee joint with an artificial joint. It is a major operation and people often experience some pain in the first three months after surgery. However, around one in five patients report moderate or severe pain after this initial three month recovery period. This is called ‘long-term’ or ‘chronic’ pain. Over 75,000 total knee replacements take place every year in the NHS. This means that approximately 15,000 people have long-term pain afterwards. People with long-term pain say that pain stops them from doing things they value, including taking part in work, family and social activities. Pain can also change a person’s mood, sometimes leading to anxiety and depression. It is known that many people do not receive or seek care for long-term pain. Improving care and support for people with long-term pain after knee replacement will benefit patients, the NHS and society. Despite efforts to prevent long-term pain, there will always be some people who need care and support after surgery. The aim of this study is to look at new care pathway to see if it is of benefit to patients with long-term pain after knee replacement.

Who can participate?
Adult patients with long-term pain after knee replacement surgery for osteoarthritis.

What does the study involve?
Participants are randomly allocated to receive treatment as usual or the STAR treatment pathway (with twice as many patients receiving the STAR treatment pathway). The STAR pathway involves a clinic appointment at 3 months after knee replacement with a healthcare professional to better understand the possible causes of pain after knee replacement. Patients are then be referred to see relevant health professionals for treatment as needed, such as physiotherapists, orthopaedic (bone) surgeons, GPs, and pain specialists. We may decide that for some people the most appropriate course of action is to regularly monitor their pain, and then begin treatment if the pain worsens. Alternatively, it may be decided that for some patients the most appropriate course of action is to regularly monitor their pain, and then begin treatment if the pain worsens. A healthcare professional continues to monitor these patients’ care over the 12 months of the project, and telephones patients up to 6 times over this period. Participants in both groups are followed up after 6 and 12 months in order to assess pain levels.

What are the possible benefits and risks of participating?
It is not known as to whether participants will benefit, as this study aims to look at whether this care pathway is beneficial. There are no notable risks involved with participating in this study, although filling in the follow up questionnaires will take time.

Where is the study run from?
Southmead Hospital (lead centre) and three other hospitals in England and Wales (UK)

When is the study starting and how long is it expected to run for?
November 2015 to August 2020

Who is funding the study?
National Institute for Health Research (UK)

Who is the main contact?
Ms Wendy Bertram

Trial website

Contact information



Primary contact

Ms Wendy Bertram


Contact details

Musculoskeletal Research Unit
School of Clinical Sciences
University of Bristol
Level 1
Learning & Research Building
Southmead Hospital
Southmead Road
BS10 5NB
United Kingdom
+44 117 414 7848

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title

The STAR trial: Evaluation of a care pathway for patients with long-term pain after knee replacement



Study hypothesis

The primary aim of this study is to evaluate the clinical effectiveness of a new care pathway (‘the STAR pathway’) compared to usual care for people with long-term pain after knee replacement.

Ethics approval

South West – Central Bristol Research Ethics Committee, 07/07/2016, ref: 16/SW/0154

Study design

Randomised; Interventional; Design type: Treatment, Complex Intervention

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


Specialty: Musculoskeletal disorders, Primary sub-specialty: Musculoskeletal pain disorders; UKCRC code/ Disease: Musculoskeletal/ Arthrosis


Patients with long-term pain at three months after knee replacement will be randomised with a 2:1 intervention:control randomisation ratio through an online system provided by the Bristol Randomised Trials Collaboration.

Control group: Patients will receive care as usual for the duration of the study.

Intervention group: Patients will be invited to a one hour assessment clinic three months after their knee replacement with an Extended Scope Practitioner to identify potential causes of pain and will then be referred onwards to appropriate existing services. Patients will also receive up to 6 telephone follow-up calls from the Extended Scope Practitioner over the 12 month follow-up period.

Participants in both groups complete follow up questionnaires at six and 12 months post- randomisation. Costs and resource use are also monitored over the 12 month follow-up period.

Intervention type



Drug names

Primary outcome measures

Pain intensity and pain interference are assessed using the Brief Pain Inventory at baseline and 12 months after randomisation.

Secondary outcome measures

1. Pain and physical functioning are measured using the Brief Pain Inventory (at baseline and 6 months) and Oxford Knee Score (OKS) at baseline, 6 and 12 months
2. Pain description is assessed using PainDETECT and Douleur Neuropathique 4 (DN-4) at baseline, 6 and 12 months
3. Emotional aspects of pain are measured using the Hospital Anxiety and Depression Scale (HADs), Pain Catastrophizing Scale (PCS), and Possible Solutions to Pain Questionnaire (PaSol) at baseline, 6 and 12 months
4. Use of pain medications is measured using Resource use questions at baseline, 6 and 12 months
5. Improvement and satisfaction with pain relief is measured using the Self-Administered Patient Satisfaction Scale (single-item question on comparison of pain to pre-operative pain) at baseline, 6 and 12 months
6. Temporal aspects of pain are measured using Single-item questions on pain frequency during past 24 hours and 4 weeks, at baseline, 6 and 12 months
7. Capability is measured using the ICECAP-A at baseline, 6 and 12 months
8. Health-related quality of life is measured using EQ-5D-5L and Short Form-12 (SF-12) at baseline, 6 and 12 months
9. Pain elsewhere is assessed using a body diagram to assess chronic widespread pain at baseline, 6 and 12 months
10. Resource use is measured as use of health services including primary, secondary and tertiary care; use of personal social services; additional costs (travel, lost income, home modifications) using follow-up trial questionnaires at 12 months. Resource use data including inpatient stays and outpatient visits for all patients will be obtained from hospital electronic systems. If this is not possible, they will be extracted from hospital records and recorded on standardised proformas.

Overall trial start date


Overall trial end date


Reason abandoned


Participant inclusion criteria

1. Patients aged 18 years and over
2. Patients who received a primary total knee replacement for osteoarthritis at a participating NHS Trust
3. Patients who have pain in their operated knee at 2-3 months after surgery, defined as a score of ≤14 on the 7 pain items of the Oxford Knee Score

Participant type


Age group




Target number of participants

Planned Sample Size: 380; UK Sample Size: 380

Participant exclusion criteria

1. Lack of capacity to provide informed consent to participate
2. Previously participating in the STAR trial for contralateral knee
3. Taking part in another research study that interferes unacceptability with STAR (or vice versa)

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

Southmead Hospital
Southmead Road Westbury-on-Trym
BS10 5NB
United Kingdom

Trial participating centre

Royal Devon and Exeter Hospital
Knee Unit Princess Elizabeth Orthopaedic Centre Barrack Road
United Kingdom

Trial participating centre

University Hospital Llandough
Penlan Road Penarth
CF64 2XX
United Kingdom

Trial participating centre

Nuffield Orthopaedic Centre
Windmill Road Headington
United Kingdom

Sponsor information


North Bristol NHS Trust

Sponsor details

Research and Innovation
3rd Floor
Learning and Research Building
Southmead Hospital
Southmead Road
BS10 5NB
United Kingdom

Sponsor type

Hospital/treatment centre



Funder type


Funder name

National Institute for Health Research

Alternative name(s)


Funding Body Type

government organisation

Funding Body Subtype

Federal/National Government


United Kingdom

Results and Publications

Publication and dissemination plan

All manuscripts resulting from the trial will be published open access in line with NIHR guidance. Publications will include a final report, as well as presentations at scientific meetings and publication of findings in scientific literature.
The trial protocol will be published in 2017 and the main trial results paper in 2020.
In addition, all participants in the trial will be sent a summary of the final results written in plain English.

Intention to publish date


Participant level data

Stored in repository

Results - basic reporting

Publication summary

Publication citations

Additional files

Editorial Notes

21/09/2016: Internal review.