Plain English Summary
Background and study aims
Osteoarthritis is a condition that causes joints to become painful and stiff. Hip osteoarthritis can be treated with hip replacement surgery, where the damaged hip joint is replaced with an artificial implant. The surgeon has various choices as to which implant they use. The implant that surgeons routinely use comes in two different lengths: the original (150mm) length or the ‘short’ (125mm) length. It is not known whether patient outcomes differ based on the length of the implant used. The aim of this study is to find out whether the length of the hip replacement stem has any influence on pain and physical function after total hip replacement.
Who can participate?
Patients aged 45-80 undergoing total hip replacement for osteoarthritis
What does the study involve?
Participants are randomly allocated to receive either an ‘original’ (150mm) or ‘short’ (125mm) stem as part of routine total hip replacement at the study centre. Hip function, quality of life, pain, joint awareness, satisfaction and implant position are measured at the start of the study and after 1 and 2 years.
What are the possible benefits and risks of participating?
It is thought that the length of stem does not affect patient recovery or outcomes after surgery in any way. Participants do not directly benefit from taking part in this study, but the knowledge gained may benefit other people by helping to find the best way to treat people who need total hip replacement in the future. Both stem lengths are available for routine use in the study centres, and as such there are no additional risks in taking part in this study beyond those of having routine total hip replacement surgery.
Where is the study run from?
1. Royal Infirmary of Edinburgh (UK)
2. Golden Jubilee National Hospital (UK)
When is the study starting and how long is it expected to run for?
January 2016 to December 2019
Who is funding the study?
Who is the main contact?
Dr David Hamilton
Can Arthroplasty Stem INfluence Outcome? (CASINO): a randomised controlled equivalence trial of 125mm vs 150mm Exeter stems in total hip arthroplasty
That the use of the 125mm ExeterTM stem in routine total hip arthroplasty achieves equivalent short-term (up to 2 years post-op) patient-reported and radiographic outcomes as the 150mm Exeter stem.
South East Scotland Research Ethics Committee 02, 12/05/2017, ref:16/SS/0176
Multi-centre prospective randomised controlled trial
Primary study design
Secondary study design
Randomised controlled trial
Patient information sheet
Not currently available in web format, please use contact details to request a participant information sheet
Patients will be randomised on a 1:1 ratio to receive either an ‘original’ (150mm) or ‘short’ (125mm) ExeterTM stem as part of routine total hip arthroplasty at the study centre. Randomisation will be by computer generated number, stratified by centre using random block sizes.
A standard operative technique will be employed by all trial surgeons; using the posterior approach, ExeterTM femoral component and ContemporaryTM acetabular component (Stryker). All implants will be cemented. The routine post-operative patient care protocol of the study centre will be employed.
Primary outcome measures
Patient reported function, measured using the Oxford Hip Score at baseline, 1 year and 2 years
Secondary outcome measures
1. Quality of life, measured using the EQ5D-5L questionnaire at baseline, 1 year and 2 years
2. Pain, measured using the visual analogue scale at baseline, 1 year and 2 years
3. Joint awareness, measured using the Forgotten Joint Score-12 at baseline, 1 year and 2 years
4. Satisfaction, measured using a satisfaction Likert response scale at 1 and 2 years
5. Radiographic implant position, measured using AP pelvis radiographs at 1 year
Overall trial start date
Overall trial end date
Participant inclusion criteria
1. Planned total hip replacement for osteoarthritis
2. Planned primary hip arthroplasty with standard implants
3. Patients aged 45-80
4. Patient willing and able to comply to the study protocol
Target number of participants
Participant exclusion criteria
1. Dysplasia of the hip/acetabulum
2. Requirement for acetabular bone grafting
3. Planned bilateral procedures within the trial period
4. Activity-limiting pain in either knee or contralateral hip
5. Procedures done for pain relief (such as for patients with no walking capacity)
6. Already recruited to the trial
Recruitment start date
Recruitment end date
Countries of recruitment
Trial participating centre
Royal Infirmary of Edinburgh
Trial participating centre
Golden Jubilee National Hospital
ACCORD; The University of Edinburgh & NHS Lothian
The Queen’s Medical Research Institute
47 Little France Crescent
Funding Body Type
private sector organisation
Funding Body Subtype
United States of America
Results and Publications
Publication and dissemination plan
Publication of trial results will be sought through high-ranked peer reviewed speciality journals with an expectation of publication 1 year following the end of the last patient follow-up.
IPD sharing statement
The current data sharing plans for the current study are unknown and will be made available at a later date.
Intention to publish date
Participant level data
To be made available at a later date
Results - basic reporting