Does the Corin Optimised Positioning System Improve Clinical Outcome in Total Hip Arthroplasty? A Multi-centre, Two-arm Randomised Control Trial
Phase: NA
Conditions: Osteoarthritis, Hip, Osteoarthritis, Arthritis, Musculoskeletal Diseases or Conditions
Sponsor: University of Oxford

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Does the Corin Optimised Positioning System improve clinical outcome in total hip replacement? 
Chief Investigator: Professor Siôn Glyn-Jones 
IRAS Project Number: 216084 
 
Rec Reference Number: 17/SC/0506 
 
 
 
Trial Title:  Does the Corin Optimised Positioning System improve clinical outcome in total hip 
arthroplasty? A multi-centre, two-arm randomised control trial 
Internal Reference Number / Short title: The HAPI Study (Hip Arthroplasty Positioning Improvement) 
Ethics Ref: 17/SC/0506 
IRAS Ref. 216084 
Date and Version No: 10/11/2017 v1.2 
 
Chief Investigator: 
Professor Siôn Glyn-Jones 
Professor of Orthopaedic Surgery and Consultant Orthopaedic 
Surgeon, University of Oxford 
 
Co-investigators 
Mr Adrian Taylor, Consultant Orthopaedic Surgeon, Oxford University 
Hospitals NHS Foundation Trust 
Mr Ben Kendrick, Consultant Orthopaedic Surgeon, Oxford University 
Hospitals NHS Foundation Trust 
Dr Rory Ferguson, Clinical Research Fellow, University of Oxford 
Complete list of study team members and participating site contact 
details on file 
 
Sponsor:  
University of Oxford   
Clinical Trials & Research Governance 
Joint Research Office,  
Block 60,  
Churchill Hospital 
Old Road,  
Headington 
Oxford, OX3 7LE 
 
 
Funder:  
Corin Limited 
Chief Investigator Signature:  
 
 
 
 

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Does the Corin Optimised Positioning System improve clinical outcome in total hip replacement? 
Chief Investigator: Professor Siôn Glyn-Jones 
IRAS Project Number: 216084 
 
Rec Reference Number: 17/SC/0506 
 
 
 
 
 
Confidentiality Statement 
This document contains confidential information that must not be disclosed to anyone other than the 
Sponsor, the Investigator Team, HRA, host organisation (Nuffield Department of Orthopaedics, 
Rheumatology and Musculoskeletal Sciences, University of Oxford), and members of the Research Ethics 
Committee, unless authorised to do so. There are no conflicts of interest to declare. 
 
 

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Does the Corin Optimised Positioning System improve clinical outcome in total hip replacement? 
Chief Investigator: Professor Siôn Glyn-Jones 
IRAS Project Number: 216084 
 
Rec Reference Number: 17/SC/0506 
 
TABLE OF CONTENTS 
1. 
KEY TRIAL CONTACTS ............................................................................................................................ 4 
2. 
SYNOPSIS............................................................................................................................................... 5 
3. 
ABBREVIATIONS .................................................................................................................................... 6 
4. 
BACKGROUND AND RATIONALE ........................................................................................................... 7 
5. 
OBJECTIVES AND OUTCOME MEASURES .............................................................................................. 8 
6. 
TRIAL DESIGN ........................................................................................................................................ 9 
7. 
PARTICIPANT IDENTIFICATION ........................................................................................................... 11 
7.1. 
Trial Participants ........................................................................................................................ 11 
7.2. 
Inclusion Criteria ........................................................................................................................ 11 
7.3. 
Exclusion Criteria ........................................................................................................................ 11 
8. 
TRIAL PROCEDURES ............................................................................................................................ 11 
8.1. 
Recruitment ............................................................................................................................... 11 
8.2. 
Screening and Eligibility Assessment ......................................................................................... 13 
8.3. 
Informed Consent ...................................................................................................................... 13 
8.4. 
Randomisation, blinding and code-breaking ............................................................................. 14 
8.5. 
Baseline Assessments ................................................................................................................ 14 
8.6. 
Summary of Patient Visits .......................................................................................................... 15 
9. 
DESCRIPTION OF PROCEDURES .......................................................................................................... 17 
9.1. 
Discontinuation/Withdrawal of Participants from Trial Treatment .......................................... 18 
9.2. 
Definition of End of Trial ............................................................................................................ 19 
10. SAFETY REPORTING............................................................................................................................. 19 
11. STATISTICS .......................................................................................................................................... 20 
11.1. 
The Number of Participants ....................................................................................................... 20 
11.2. 
Description of Statistical Methods ............................................................................................. 21 
11.3. 
The Level of Statistical Significance ........................................................................................... 21 
11.4. 
Criteria for the Termination of the Trial .................................................................................... 21 
11.5. 
Procedure for Accounting for Missing, Unused, and Spurious Data ......................................... 21 
11.6. 
Inclusion in Analysis ................................................................................................................... 21 
11.7. 
Procedures for Reporting any Deviation(s) from the Original Statistical Plan ........................... 21 
12. DATA MANAGEMENT ......................................................................................................................... 22 
12.1. 
Access to Data ............................................................................................................................ 22 
12.2. 
Data Recording and Record Keeping ......................................................................................... 22 
13. QUALITY ASSURANCE PROCEDURES ................................................................................................... 22 

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Does the Corin Optimised Positioning System improve clinical outcome in total hip replacement? 
Chief Investigator: Professor Siôn Glyn-Jones 
IRAS Project Number: 216084 
 
Rec Reference Number: 17/SC/0506 
 
14. OTHER ETHICAL CONSIDERATIONS ..................................................................................................... 22 
14.1. 
Declaration of Helsinki ............................................................................................................... 23 
14.2. 
Guidelines for Good Clinical Practice ......................................................................................... 23 
14.3. 
Approvals ................................................................................................................................... 23 
14.4. 
Reporting .................................................................................................................................... 23 
14.5. 
Participant Confidentiality ......................................................................................................... 24 
14.6. 
Expenses and Benefits ............................................................................................................... 24 
14.7. 
Other Ethical Considerations ......................................................... Error! Bookmark not defined. 
15. FINANCE AND INSURANCE .................................................................................................................. 24 
15.1. 
Funding....................................................................................................................................... 24 
15.2. 
Insurance .................................................................................................................................... 24 
16. PUBLICATION POLICY .......................................................................................................................... 24 
17. REFERENCES ........................................................................................................................................ 24 
18. APPENDIX A:  TRIAL FLOW CHART ...................................................................................................... 26 
19. APPENDIX B:  SCHEDULE OF PROCEDURES ......................................................................................... 27 
20. APPENDIX C:  AMENDMENT HISTORY ................................................................................................ 28 
 
1. KEY TRIAL CONTACTS 
Chief Investigator 
Professor Siôn Glyn-Jones 
Nuffield department of Orthopaedics, Rheumatology and 
Musculoskeletal science, 
NIHR Bio-Medical Research Unit, 
Oxford University 
OX3 7LD 
Sion.glyn-jones@ndorms.ox.ac.uk 
01865 737839 
Sponsor 
University of Oxford  
Clinical Trials & Research Governance 
Joint Research Office,  
Block 60,  
Churchill Hospital 
Old Road,  
Headington 
Oxford, OX3 7LE 
Clinical Trials Unit 
Nuffield department of Orthopaedics, Rheumatology and 
Musculoskeletal science, 
NIHR Bio-Medical Research Unit, 
Oxford University 

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Does the Corin Optimised Positioning System improve clinical outcome in total hip replacement? 
Chief Investigator: Professor Siôn Glyn-Jones 
IRAS Project Number: 216084 
 
Rec Reference Number: 17/SC/0506 
 
OX3 7LD 
01865 227374 
brc.reception@ndorms.ox.ac.uk 
 
2. SYNOPSIS 
Trial Title 
Does the Corin Optimised Positioning System improve clinical outcome 
in total hip arthroplasty? A multi-centre, two-arm randomised controlled 
trial 
 
Internal ref. no. (or 
short title) 
The HAPI Trial 
Trial Design 
Single-blinded randomised controlled trial comparing best practice total 
hip arthroplasty (THA) surgical technique and templating with the best 
practice THA surgical technique plus Corin Optimised Positioning System 
(OPS) to guide templating. We will perform an internal pilot after 100 
participants have been recruited. If analysis shows the trial is feasible, 
we will then progress onto the full study. 
Trial Participants 
Male and female adults between 18 and 85 years of age, with a 
dysfunctional hip caused by osteoarthritis (OA), post traumatic OA, 
inflammatory 
arthropathy, 
avascular 
necrosis 
and 
congenital/ 
developmental problems, randomly selected from the THA waiting list at 
each participating centre. 
Planned Sample Size 
460 participants. 230 patients will receive best practice THA with 
conventional templating; the other 230 will receive best practice THA 
with Corin OPS to guide templating. Patients who drop out will not be 
replaced. 
The first 100 patients will constitute an internal pilot: results of the 
internal pilot will be used to repower the study. We anticipate the 
projected sample size of 460 may change by 5% either way. 
Treatment duration 
2 years  
Follow up duration 
1 year 
Planned Trial Period 
3 years 
 
Objectives 
Outcome Measures 
Primary 
 
To compare the efficacy of the 
Corin OPS system to guide 
templating in THA with standard 
templating in THA in reducing 
dislocation 
Dislocation rate and re-operation 
for dislocation rate 
 
 
Secondary 
 
1, To determine whether the 
Corin OPS System improves Harris 
hip score, patient reported 
outcome measures (PROMs), 
reduces hospital stay and 
normalises gait more effectively 
than conventional surgery 
 
1, PROMs: 
 
Oxford hip score (OHS) 
 
iHOT33 
 
HAGOS 
 
Pain detect 
 
EQ5D 
 
UCLA score 

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Does the Corin Optimised Positioning System improve clinical outcome in total hip replacement? 
Chief Investigator: Professor Siôn Glyn-Jones 
IRAS Project Number: 216084 
 
Rec Reference Number: 17/SC/0506 
 
2, To determine whether the 
Corin OPS System improves leg 
length discrepancy compared to 
conventional surgery 
 
3, To quantify the cost of Corin 
OPS within the clinical pathway 
and perform a full health 
economic analysis following 
surgery 
 
4, To determine the 
reproducibility of the Corin OPS 
templating technique at 
implanting the acetabular cup 
into the planned position. This 
will be performed in a subgroup 
of 50 patients randomly selected 
from the OPS arm to undergo a 
post-operative CT scan 
 
5, To determine whether the 
Corin OPS System increases 
operation duration compared to 
conventional surgery 
Harris hip score (HHS) 
Length of hospital stay 
Gait analysis 
Cost analysis 
 
2, Leg length measurement 
 
3, Cost  
 
4, Post-operative position of 
prosthesis measured relative to 
planned position, based on pre- 
and post-operative CT scans 
 
5, Operation duration 
 
3. ABBREVIATIONS 
AE 
Adverse event 
AR  
Adverse reaction 
CI 
Chief Investigator 
CRF 
Case Report Form 
CT 
Computed Tomography 
CTRG 
Clinical Trials and Research Governance 
DMC 
Data Monitoring Committee  
EQ-5D 
Euro-Qol Group 5-Dimensions Questionnaire 
GCP 
Good Clinical Practice 
GP 
General Practitioner 
HAGOS 
Copenhagen Hip and Groin Outcome Score 
HHS 
Harris Hip Outcome 
HRA 
Health Research Authority 
ICF 
Informed Consent Form 

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Does the Corin Optimised Positioning System improve clinical outcome in total hip replacement? 
Chief Investigator: Professor Siôn Glyn-Jones 
IRAS Project Number: 216084 
 
Rec Reference Number: 17/SC/0506 
 
ICH 
International Conference on Harmonisation 
iHOT33 
International Hip Outcome Tool-33 
NHS 
National Health Service 
NRES 
National Research Ethics Service  
OA 
Osteoarthritis 
OHS 
Oxford Hip Score 
OPS 
Optimised Positioning System 
PI 
Principal Investigator 
PIL 
Participant/ Patient Information Leaflet 
PROM 
Patient Reported Outcome Measure 
R&D 
NHS Trust R&D Department 
REC 
Research Ethics Committee 
SAE 
Serious Adverse Event 
SOP 
Standard Operating Procedure 
SUSAR 
Suspected Unexpected Serious Adverse Reactions 
THA 
Total Hip Arthroplasty 
TMF 
Trial Master File 
UCLA score 
University of California, Los Angeles Activity Score 
 
4. BACKGROUND AND RATIONALE 
Osteoarthritis (OA) is the most common joint disease worldwide affecting an estimated 10% of males and 
18% of females over 60 years of age1. The resultant pain and loss of function can be debilitating and in 
developed countries represents a large socioeconomic burden, costing between 1% and 2.5% of gross 
domestic product, which currently stands at over £1.5 trillion2. Total hip arthroplasty (THA) is an effective 
treatment for end-stage hip arthritis; however, demand for the procedure is growing rapidly, fuelled by an 
ageing population and the obesity epidemic3. In fact, rates of THA are predicted to rise 174% between 
2005 and 20304. The current commissioning environment in developed countries means that investment 
in iterative improvements of existing THA implant designs are unlikely to yield either significant benefits 
to patients or be supported by health funders. The two principle issues that concern surgeons and patients 
are the longevity of implants and the ability of new technologies to minimise complications such as 
dislocation and infection. The James-Lind Priorities Setting Partnership, an internationally recognised 
patient-driven organisation, has recently identified these pre-operative and intra-operative factors as 
targets for improving outcome following hip and knee replacement5,6. 
One of the largest costs to healthcare providers following THR is dislocation7. Although the dislocation rate 
reported in Joint Registries is between 1 and 3%8,9, we know that this significantly underestimates the true 
problem, as the majority of dislocation events are managed with closed reduction and do not result in 
revision surgery10. It is estimated that dislocation is an order of magnitude more common than reported 

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Does the Corin Optimised Positioning System improve clinical outcome in total hip replacement? 
Chief Investigator: Professor Siôn Glyn-Jones 
IRAS Project Number: 216084 
 
Rec Reference Number: 17/SC/0506 
 
in Registry data. Literature estimates indicate a true dislocation prevalence of 3 to 15%9,11,12. The cost of 
dislocation is significant as the problem is often recurrent, resulting in multiple hospital admissions. The 
resulting average cost for each patient who suffers a THR dislocation is around £30,0007.  
The factors that influence dislocation are poorly understood. Conventional surgical wisdom dictates that 
placing a cup in the Lewinneck ‘safe zone’ reduces both instability and wear13. A recent study of 9784 
primary THAs, however, demonstrated that 58% of patients who suffered a dislocation had implants 
judged to be in a safe position14. This has led to suggestions that the idea of one generic ‘safe zone’ may 
be misleading14,15; instead, there is a unique optimum position to place a cup in each patient undergoing 
THA, based on the unique and complex interaction of the spine and pelvis of the individual. Thus, in some 
patients, whilst the acetabular cup appears well positioned by conventional measures, pelvic tilt and spinal 
position mean that the cup is placed in a position of instability during some activities. 
The Corin Optimised Positioning System (OPS) is a novel platform, designed to enable delivery of the 
prosthetic acetabular cup into an optimised position for every patient undergoing THA16. It comprises two 
stages: pre-operative planning and intra-operative guidance. Pre-operatively, patients undergo dynamic 
imaging (computed tomography scanning and X-ray films). The information gained about the relative 
movements of a patient’s spine, pelvis and hips are used to create a personalized physiological profile. This 
enables calculation of the optimized acetabular cup orientation for each individual. A unique physical guide 
(which falls under the definition of a custom-made device in the Medical Device Directive) is then created 
for each patient to fit precisely into the acetabular fossa, for use intra-operatively. Intra-operatively, the 
Corin OPS uses laser alignment to aid the surgeon in aligning the acetabular cup in the calculated optimised 
orientation. One laser is affixed to an immovable pelvic screw; the other is attached to the reverse of the 
acetabular cup. The target orientation of the cup is achieved when the two lasers are aligned.  
The aim of this trial is to assess the efficacy of the use of the Corin Optimised Positioning System in reducing 
post-operative hip dislocation in patients undergoing total hip arthroplasty by comparing it with current 
standard templating in total hip arthroplasty. All total hip implants/components used in the study will be 
produced by Corin for uniformity and are CE marked. There is currently no evidence that this novel 
approach to templating has an effect on dislocation rate. This project aims to provide evidence that this 
new technique can improve outcomes for patients and have the potential to reduce the need for complex, 
expensive revision surgery. 
5. OBJECTIVES AND OUTCOME MEASURES 
Objectives 
Outcome Measures  
Timepoint(s) of 
evaluation of this 
outcome measure 
(if applicable) 
Primary Objective 
To compare the efficacy of the Corin 
OPS system to guide templating in 
THA with standard templating in 
THA in reducing dislocation  
Dislocation rate and re-operation for 
dislocation rate 
Pre-operatively, 
then at 3,6 and 12 
months post-
operatively 

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Does the Corin Optimised Positioning System improve clinical outcome in total hip replacement? 
Chief Investigator: Professor Siôn Glyn-Jones 
IRAS Project Number: 216084 
 
Rec Reference Number: 17/SC/0506 
 
Secondary Objectives 
1, To determine whether the Corin 
OPS System improves Harris hip 
score, patient reported outcome 
measures (PROMs), reduces 
hospital stay and normalises gait 
more effectively than conventional 
surgery 
2, To determine whether the Corin 
OPS System improves leg length 
discrepancy compared to 
conventional surgery 
3, To quantify the cost of Corin OPS 
within the clinical pathway and 
perform a full health economic 
analysis following surgery 
4, To determine the reproducibility 
of the Corin OPS templating 
technique at implanting the 
acetabular cup into the planned 
position. This will be performed in a 
subgroup of 50 patients randomly 
selected from the OPS arm to 
undergo a post-operative CT scan 
5, To determine whether the Corin 
OPS System increases operation 
duration compared to conventional 
surgery 
1, PROMs: 
 
Oxford hip score (OHS) 
 
iHOT33 
 
HAGOS 
 
Pain detect 
 
EQ5D 
 
UCLA 
Harris hip score (HHS) 
Length of hospital stay 
Gait analysis 
 
2, Measurement of leg lengths 
 
3, Cost of inpatient stay for THA and cost 
of all patient care pertaining to their THA 
 
4, Post-operative position of prosthesis 
measured relative to planned position, 
based on pre- and post-operative CT 
scans 
 
5, Operation duration 
1, PROMS and HHS 
recorded pre-
operatively, then at 
3, 6 and 12 months 
post-operatively. 
Gait analysis pre-
operatively and at 
12 months post-
operatively (25 
patients in each 
arm). Length of 
hospital stay will be 
recorded on 
discharge 
2, X-rays and leg 
lengths will be 
assessed pre-
operatively, then at 
12 months post-
operatively 
3, Cost calculated 
12 months post-
operatively 
4, CT scans pre-
operatively and at 
12 months post-
operatively 
5, Recorded at end 
of operation 
6. TRIAL DESIGN 
This will be a multi-centre, two-arm, single blind (participant blind), randomised controlled group 
superiority study. It will take place in the NHS hospital setting. Stratification will be performed for age and 
sex by means of a minimisation technique during randomisation for each subject entering the trial. There 
will be no limit on the number of sites and no limit on the number of recruits per site. The study site shall 
maintain a list of the participating sites and investigators separately to the protocol. 
Arm 1 
Best practice total hip arthroplasty with conventional templating 
Arm 2 

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Does the Corin Optimised Positioning System improve clinical outcome in total hip replacement? 
Chief Investigator: Professor Siôn Glyn-Jones 
IRAS Project Number: 216084 
 
Rec Reference Number: 17/SC/0506 
 
Best practice total hip arthroplasty with Corin Optimised Positioning System to guide templating 
In the study 230 participants will receive best practice THA with conventional templating; the other 230 
will receive best practice THA with Corin OPS to guide templating. Any participant that withdraws from the 
study will not be replaced. 
Initially we will perform an internal pilot study of 100 participants, with 50 participants in each arm. This 
will enable us to check feasibility of recruitment and to check our power calculation is correct. We 
anticipate recruitment to the pilot study will take six months, with an average of four participants recruited 
per week. Together the five centres currently recruited performed 3419 primary total hip replacements in 
2015, an average of 66 per week8. Since participants in the two arms receive the same procedure, with the 
difference being in the technique used, with clear explanation of the trial to potential participants, we 
anticipate that approximately 50% of eligible patients that are approached will consent to take part in the 
trial. With this knowledge, we believe recruitment of initially four (rising to six) participants per week will 
be attainable. If the internal pilot study shows that completing the study is unfeasible, then the trial will 
be terminated following mutual agreement from both the Chief Investigator and the funder (Corin 
Limited). We anticipate recruitment to the full trial will take two years. 
The expected duration of participant participation is 15 months. Following recruitment in outpatient 
clinics, participants will undergo baseline assessments, including imaging (CT scan and x-rays of pelvis) and 
clinical assessment. A subset of 50 participants will be randomly selected to also undergo gait analysis as 
part of the baseline assessments pre-operatively. All participants will then undergo THA surgery, which 
will likely entail an in-patient hospital stay of 1-7 days. Post-operative rehabilitation will be in line with the 
normal standard care for all participants. Post-operatively participants will make three additional visits to 
clinic at 3, 6 and 12 months, compared to routine follow up. At every visit, participants will complete the 
PROM questionnaires and undergo clinical assessment, as specified in section 5. Any dislocations or further 
surgeries will be recorded. All healthcare visits will be recorded, to enable cost analysis. At the 12 month 
post-operative visit participants will have standardised anteroposterior and lateral X-rays taken. At the 12-
month visit, the subset of participants who were selected to undergo gait analysis pre-operatively will 
undergo repeat gait analysis. The subset of 50 patients who were randomly selected to undergo a second 
pelvic CT scan, will have this scan performed at the 12-month visit. Any patients in the study who do suffer 
a dislocation will be managed in line with the normal standard care. See sections 8.5 and 8.6 for more 
detail on visit schedule. 
There will also be a third observational arm to the study. When patients are approached in clinic and 
offered entry into the randomised controlled trial, some patients may decline to take part. These patients 
will then be offered entry into the third observational arm of the study. This third study arm therefore will 
consist solely of patients who were approached in clinic but declined to be randomised into the clinical 
trial. 
Patients in the third observational arm will continue in routine care as normal, and will not make any 
additional study visits. Their demographics will be collected and their pre- and post-operative Oxford hip 
scores and EQ-5D scores will be collected, as occurs in routine care. This third observational study arm will 
enable an assessment of whether the cohort who consented to undergo randomisation and enter the two 
randomised study arms are representative of all patients. 

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Does the Corin Optimised Positioning System improve clinical outcome in total hip replacement? 
Chief Investigator: Professor Siôn Glyn-Jones 
IRAS Project Number: 216084 
 
Rec Reference Number: 17/SC/0506 
 
7. PARTICIPANT IDENTIFICATION 
7.1. Trial Participants 
Trial participants will be male and female adults between 18 and 85 years of age, with a diagnosis of hip 
OA, post-traumatic OA, inflammatory arthropathy, avascular necrosis, or congenital/developmental hip 
disease. Their disease is severe enough to warrant total hip arthroplasty (THA). Once recruitment begins, 
patients meeting the inclusion criteria will be identified at consultant-led outpatient and pre-operative 
assessment clinics at each participating centre. Patients will be approached during clinic appointments and 
offered entry into the trial.  
7.2. Inclusion Criteria 
 
Participant is willing and able to give informed consent for participation in the trial 
 
Male or Female, aged 18 to 85 years at recruitment into trial 
 
Diagnosed with hip OA, post-traumatic OA, inflammatory arthropathy, avascular necrosis, or 
congenital or developmental hip disease, avascular necrosis of the hip 
 
Listed for total hip arthroplasty at one of participating centres 
 
Female participants of child bearing potential must be willing to ensure that they use effective 
contraception during the trial 
 
Participant is fit to undergo total hip arthroplasty based on consultant anaesthetist review  
 
In the Investigator’s opinion, is able and willing to comply with all trial requirements 
 
Willing to allow his or her General Practitioner and consultant, if appropriate, to be notified of 
participation in the trial 
7.3. Exclusion Criteria 
The participant may not enter the trial if ANY of the following apply: 
 
Inability to provide informed consent 
 
Previous surgery to the ipsilateral hip 
 
Significant co-morbidities that would make follow up difficult or uncomfortable 
 
Scheduled elective surgery or other procedures requiring general anaesthesia during the trial 
 
Pregnancy 
 
8. TRIAL PROCEDURES 
8.1. Recruitment 

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Does the Corin Optimised Positioning System improve clinical outcome in total hip replacement? 
Chief Investigator: Professor Siôn Glyn-Jones 
IRAS Project Number: 216084 
 
Rec Reference Number: 17/SC/0506 
 
Once recruitment begins, potential participants will be identified at consultant-led outpatient and pre-
operative assessment clinics at each participating centre. During clinic appointments, orthopaedic 
surgeons will introduce the study to patients and refer them to a member of the study team, who will also 
be present in clinic, to discuss the study in detail and provide any further information requested. Patients 
will be asked to “opt-in” if they are provisionally interested in participating. If patients agree to “opt-in” 
they will be asked to sign the opt-in form and leave their contact details on a document detailing their 
agreement and permission to being contacted by a member of the research team to further discuss the 
study. Signing this document does not confer consent to participating in the study, simply to being 
contacted to further discuss the study. If potential participants do not wish to opt-in and are not interested 
in participating in the randomised study, they will be offered entry into the third observational study arm 
at this point.  
After signing the “opt-in” document, potential participants will then be given a minimum of 48 hours to 
consider the study information and to discuss the study with their family and GP should they desire. 
Potential participants will then be contacted by telephone. At this time, any further questions will be 
addressed, and if the individual would like to participate in the study, a consent visit will be arranged for 
consenting. It is proposed that these appointments will occur within four weeks of the initial approach. If 
when contacted by telephone potential participants decline to take part in the randomised study, they will 
be offered entry into the third observational study arm. 
At the consent appointment participants will meet with a member of the research team again to discuss 
the process and to discuss the study further. The surgeon may also attend this visit. It will be clearly stated 
that the participant is free to withdraw from the study at any time for any reason without prejudice to 
future care, and with no obligation to give the reason for withdrawal. The research nurse obtaining consent 
will be suitably qualified and experienced. A copy of the signed Informed Consent will be given to the 
participants and the original signed form will be retained at the study site.  
After participants have consented to take part in the randomised study, randomisation will occur and the 
baseline assessment visit will be scheduled. For participants in the third observational arm of the study, 
they will continue in routine care as normal with no further study visits. Their demographic data and pre- 
and post-operative OHS and EQ5D, collected routinely, will be recorded for the study. 

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Does the Corin Optimised Positioning System improve clinical outcome in total hip replacement? 
Chief Investigator: Professor Siôn Glyn-Jones 
IRAS Project Number: 216084 
 
Rec Reference Number: 17/SC/0506 
 
 
8.2. Screening and Eligibility Assessment 
After consent to take part has been given the following information will be collected about each patient 
and recorded on the CRFs: 
 
Demographics 
o Date of birth, gender, BMI, height, weight, and smoking status 
 
Medical history 
o Details of history of disease or surgical intervention in the following systems: inflammatory 
joint disease, previous surgery, previous joint infections, contralateral hip disease 
 
Concomitant medication 
o All over the counter or prescription medication  
The maximum time between screening and randomisation is one year. 
8.3. Informed Consent 
The participant must personally sign and date the latest approved version of the Informed Consent form 
before any trial specific procedures are performed. 
Written and verbal versions of the Participant Information and Informed Consent will be presented to the 
participants detailing no less than: the exact nature of the trial; what it will involve for the participant; the 
implications and constraints of the protocol; the known side effects and any risks involved in taking part. 
It will be clearly stated that the participant is free to withdraw from the trial at any time for any reason 
without prejudice to future care, without affecting their legal rights and with no obligation to give the 
reason for withdrawal. 
Patient approached in 
Out Patient Clinic
Final decision made at 
POAC
Consent, Basic Dataset, 
Examination & Imaging
Randomisation by 
independent investigator
Patient approached in 
POAC
Final decision made at 
pre-op research clinic
Consent, Basic Dataset, 
Examination & Imaging
Randomisation by 
independent investigator

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The participant will be allowed as much time as wished to consider the information, and the opportunity 
to question the Investigator, their GP or other independent parties to decide whether they will participate 
in the trial. Written Informed Consent will then be obtained by means of participant dated signature and 
dated signature of the person who presented and obtained the Informed Consent. The person who 
obtained the consent must be suitably qualified and experienced, and have been authorised to do so by 
the Chief/Principal Investigator. A copy of the signed Informed Consent will be given to the participant. 
The original signed form will be retained at the study site. 
8.4. Randomisation, blinding and code-breaking 
Following written informed consent and confirmation of eligibility, all patients will be randomised into the 
study. Patients will be allocated a study number and will be randomised on a 1:1 basis to receive one of 
the two treatment options. During study recruitment, 50 participants (25 in each study arm) will be 
randomly selected to undergo gait analysis. At the end of study recruitment, 50 participants will be 
randomly selected from arm 2 (OPS arm) of the study cohort to have a second CT scan, which will be 
performed at 12-months post-operatively.  
Randomisation will be performed using an automated computer-generated minimisation system through 
the Oxford Surgical Interventional Trials Unit to age (<40, ≥40 and <65, or ≥65), and gender. This process 
will occur centrally in Oxford and be overseen by the trial coordinator. Investigators at other sites will 
contact the site in Oxford to get each participant’s randomisation allocation. Patients will be blinded as to 
which arm of the trial they have been allocated. The Oxford trial coordinator, the operating surgeon and 
the theatre staff will be unblinded and aware of which treatment arm the patient is in. The post-operative 
care team will remain blinded. 
The Oxford trial coordinator will retain a full list of all recruited patients, their anonymous code number, 
and the treatment arm they have been allocated to. Trial coordinators at other sites and all operating 
surgeons will have access to a partial list, containing the same information on patients recruited at their 
own site only. 
They will be the only people with access to this list. They will not have any role in collecting, reviewing, or 
interpreting post-operative data. Members of the research team who will be post-operatively assessing 
patients clinically, reviewing images or collecting and interpreting PROMs data will be blinded to patient 
allocation.  
We do not anticipate a situation where code breaking will be required because the surgeons are not 
blinded to which arm the patients are in. 
 
8.5. Baseline Assessments 
The follow assessments will be carried out at the baseline appointment: 
Validated Patient Reported Outcome Measures (PROMs) Questionnaires: 
Oxford hip score (OHS); International Hip Outcome Tool-33 (iHOT33); Hip and Groin Outcome 
Score (HAGOS); Pain Detect score; University of California, Los Angeles (UCLA) Activity Score; 
EuroQoL-5D score (EQ5D); Harris hip score (HHS) 

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CT scan: 
CT imaging of pelvis 
X-Ray: 
Dynamic series of x-rays of pelvis and hip  
Pregnancy test 
Clinical assessment: 
Examination of range of movement; examination of fixed flexion deformity; examination of leg 
length discrepancy 
Subset of 50 participants (25 in each arm) will undergo gait analysis. These participants will be 
randomly selected from each study arm. Participants with comorbidities that significantly affect 
their gait will be excluded from gait analysis. 
Assessors of all imaging, PROMs, and clinical assessment will be blinded to which arm of the trial patients 
were in. 
8.6. Summary of Visits 
Routine clinical practice will take priority and the study timetable has been drawn up to allow the study 
procedures to fall within current surgical waiting times. Taking part in the study, therefore, will not delay 
or expedite treatment. Below is a summary of what will take place at each visit: 
Visit 1: Consent visit 
o Scheduled within 4-6 weeks of when potential participants are initially approached 
o Consent form discussed and signed 
o Following this visit, participants will be randomised into one of the two study arms 
o If patients decline entry into the study, they will be offered entry into the 3rd observational 
arm of the study 
Visit 2:  Baseline assessment visit 
o Scheduled for soon after consent visit 
o Baseline assessments (detailed in section 8.5) completed 
Visit 3: Gait Analysis Visit (subset of patients only) 
o Scheduled for same day as or soon after baseline assessment visit (because scheduling CT 
scan and gait analysis on the same day may not be possible) 
Visit 4: Study intervention 
o Scheduled for 6-8 weeks after the baseline assessment (Thus patients will have a wait for 
surgery of approximately 3 months after entry into the study, which is in line with the 
current surgery waiting time in the participating centres.) Participants will undergo THA 
surgery in accordance with their randomisation allocation. 
o Operative details to be collected: 

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 
Date of surgery 
 
Randomisation group 
 
Name of consultant in charge of care 
 
Grade of lead surgeon 
 
Grade of assistant surgeons 
 
Operative side 
 
Duration of surgery 
 
Estimated blood loss 
 
Surgical approach 
 
ASA grade 
 
Use of systemic prophylactic therapy (antibacterial and anticoagulant) 
 
Anaesthesia type 
 
Acetabular and femoral bone quality 
 
Whether there was an attempt to correct leg length (if so, what amount 
attempted and achieved) 
 
Occurrence of per-operative complications 
 
Ease of reduction 
 
Acetabular grafting performed 
 
Femoral grafting performed 
 
Details of hip prosthetic components used – including information from device 
labels 
 
Other comments on operation 
Visit 5: 3-month post-operative visit 
o Completion of PROM questionnaires 
o Clinical assessment (to include full examination of hip joint and assessment of leg length 
discrepancy) 
o Recording of dislocations, further surgeries or adverse events  
o Recording of details of any other healthcare usage by the participants (for cost analysis) 
o Review of medical records and recording of any significant events 
Visit 6: 6-month post-operative visit 
o Completion of PROM questionnaires 
o Clinical assessment (to include full examination of hip joint and assessment of leg length 
discrepancy) 
o Recording of dislocations, further surgeries or adverse events 
o Recording of details of any other healthcare usage by the participants (for cost analysis) 
o Standardised anteroposterior and lateral x-rays taken 
o Review of medical records and recording of any significant events 
Visit 7: 12-month post-operative visit 
o Completion of PROM questionnaires 
o Clinical assessment (to include full examination of hip joint and assessment of leg length 
discrepancy) 
o Recording of dislocations, further surgeries or adverse events 
o Recording of details of any other healthcare usage by the participants (for cost analysis) 
o Standardised anteroposterior and lateral x-rays taken 
o Gait analysis performed on the subset of 50 participants randomly selected pre-
operatively 

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o Subset of 50 participants will undergo a post-operative CT scan. These 50 participants will 
be randomly selected from arm 2 (OPS arm) of the study cohort. 
o Review of medical records and recording of any significant events 
Completion of this visit marks the end of trial participation 
Reasonable travel expenses to the hospital for the additional appointments for the study purposes will be 
reimbursed. 
9. DESCRIPTION OF PROCEDURES 
 
THA will be performed under general anaesthesia or spinal anaesthesia. The surgical technique will be 
standardised across all sites. All surgeons operating within the trial perform in excess of 60 hip 
arthroplasties annually. THA will be performed via anterior, antero-lateral, lateral or posterior approach. 
The study will use the Corin Trinity shell system for the acetabular system. The study will use all compatible 
Corin stem implants (MiniHip, TriFit, MetaFix and TaperFit) for the stem implant. All head and stem sizes 
will be included in the trial. All implants will be supplied by Corin Ltd. Pre-operatively all patients (both 
arms) will undergo dynamic imaging (computer tomography scanning and X-ray films) of their pelvis and 
hips. 
 
Arm 1: Best practice total hip arthroplasty (THA) with conventional templating 
An antero-posterior view radiograph of the pelvis (with legs positioned in 15o internal rotation) and a 
lateral view radiograph of the hip are required for conventional templating. The radiographs will be 
examined pre-operatively and appropriately sized cup and stem implants selected for each patient. Intra-
operatively, the surgeon may select a different sized implant to that predicted by templating if clinically 
appropriate. 
 
Arm 2: Best practice total hip arthroplasty (THA) with Corin OPS to guide templating 
Patients in the intervention arm will undergo an identical total hip arthroplasty operation. The difference 
will be the templating procedure used to accurately align the acetabular cup. 
The pre-operative dynamic imaging of patients in the OPS arm will be used to calculate the personalised 
target orientation of the acetabular cup in each patient. A unique physical guide is then created for each 
patient, which facilitates the accurate positioning of the prosthetic acetabular cup. The guide is a model 
that fits precisely into the acetabular fossa.  
At the appropriate step during the operation, the acetabular fossa is cleared of the fat pad and remnants 
of the ligamentum teres. Cartilage is removed from areas within the acetabulum where the arms of the 
guide will sit. The guide is then placed accurately into the acetabular fossa, using guide-holding forceps. 
Five reference markings on the model assist with accurately locating the guide. Superomedial pressure is 
applied to ensure it is fully seated within the fossa and rigidly stable. An acetabular laser assembly is then 
attached to the back of the guide. A pelvic screw is screwed into the bone either around the acetabulum 
within the incision or percutaneously into the iliac crest. Once the screw is fixed rigidly, a pelvic laser 
assembly is attached to the back of the pelvic screw. The alignment of the pelvic screw laser is then 

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adjusted until the laser converges with the laser of the acetabular guide, as projected onto the operating 
theatre wall or ceiling. The pelvic laser is secured with a dial. 
The acetabular laser assembly is then detached from the guide, and the guide is removed from the 
acetabulum. The pelvic laser assembly is detached from the pelvic screw. The acetabulum is reamed as 
per the routine technique. The pelvic laser assembly is then reattached to the back of the pelvic screw. 
Care is taken not to change the direction of the pelvic laser. Next, the acetabular laser assembly is 
connected to a magnetic impactor adaptor and attached to the back of the prosthetic acetabular cup 
introducer. The cup is placed in the acetabulum and the orientation is adjusted until the acetabular laser 
converges with the pelvic laser. The pelvic laser assembly is removed and the acetabular cup is impacted. 
Note that the pelvic laser assembly can be repeatedly attached and removed to assess alignment during 
impaction. Once the cup is fully impacted in a satisfactory position, the pelvic screw can be removed, and 
the operation completed as per the routine technique. 
In both arms all intra-operative findings will be recorded on the operation note. Participants will be 
assessed post operatively by the physiotherapy and medical teams to ensure safety for discharge and 
when safe patients will be discharged home in line with standard routine care. After discharge, all patients 
will follow an identical physiotherapy regime, which will follow standard practice after total hip 
arthroplasty. 
Patients receiving the THA operation will have either a general anaesthetic or an epidural anaesthetic. The 
decision of which type of anaesthetic is given is up to the clinical judgement of the anaesthetist, and will 
be based on the patient's overall health status. For patients undergoing epidural anaesthesia, a large sterile 
sheet drape will be placed vertically at the level of the patient's abdomen during surgery. This is to both 
(1) keep the surgical field sterile and (2) completely obstruct the patient’s view of the surgical field and the 
surgeon, which could prove distressing to the patient during surgery. Furthermore, patients will be given 
strong relaxant medications during surgery, making them less aware of what is taking place. The patients 
who undergo epidural anaesthesia therefore will not be able to tell what type of templating is taking place, 
and so blinding will remain in place.  
 
9.1. Discontinuation/Withdrawal of Participants from Trial Treatment 
Each participant has the right to withdraw from the trial at any time.  In addition, the Investigator may 
discontinue a participant from the trial at any time if the Investigator considers it necessary for any reason 
including: 
 
Pregnancy 
 
Ineligibility (either arising during the trial or retrospectively having been overlooked at screening) 
 
Significant protocol deviation 
 
Significant non-compliance with trial requirements 
 
An adverse event which requires revision surgery 
 
Withdrawal of Consent 
 
Loss to follow up 
The reason for withdrawal will be recorded in the CRF. 

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If the participant is withdrawn due to an adverse event, the Investigator will arrange for follow-up visits or 
telephone calls until the adverse event has resolved or stabilised. 
9.2. Definition of End of Trial 
The end of trial is the date of the last clinic visit, at 12 months post-operatively, of the last recruited 
participant. 
10. SAFETY REPORTING 
Surgery 
All participants will be recruited from a population that are on waiting lists for total hip arthroplasty surgery 
at one of the participating centres. All procedures will be carried out in accordance with existing practice 
and therefore participation in the study will not confer any increased risk. Surgical risks are minor and rare 
but include infection, thromboembolism, persistent pain, bleeding, damage to nerves of blood vessels, 
stiffness, injuries caused by traction and failure of procedure.  
The insertion of the pelvic screw into the pelvis is the additional step in the intervention arm that carries 
risk. Risks from this part of the procedure would be similar to those of the control arm surgery itself in 
terms of pain, bleeding, infection, damage to nerves or blood vessels, or failure of procedure. The risk of 
infection in both procedures is minimised by the use of prophylactic antibiotics. Complications from the 
surgery will be monitored as per each NHS trust protocol for routine postoperative care. This involves 
regular monitoring by nursing staff and doctors for evidence of postoperative complications whilst the 
participant is an inpatient, and at every follow up visit when the patient is an outpatient. Wound sites will 
be checked for evidence of infection, collections, or failure to heal, observations will be monitored for 
signs of infection or complication, and blood tests will be monitored for evidence of bleeding, infection, or 
electrolyte imbalance. The patient will only be discharged from in-patient care once both medical and 
physiotherapy teams agree that the patient is safe for discharge as per standard postoperative protocol. 
10.1. 
Definition of Serious Adverse Events 
A serious adverse event is any untoward medical occurrence that: 
 
results in death 
 
is life-threatening 
 
requires inpatient hospitalisation or prolongation of existing hospitalisation 
 
results in persistent or significant disability/incapacity 
 
consists of a congenital anomaly or birth defect. 
Other ‘important medical events’ may also be considered serious if they jeopardise the participant or 
require an intervention to prevent one of the above consequences. 

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NOTE: The term "life-threatening" in the definition of "serious" refers to an event in which the participant 
was at risk of death at the time of the event; it does not refer to an event which hypothetically might have 
caused death if it were more severe. 
10.2. 
Reporting Procedures for Serious Adverse Events 
A serious adverse event (SAE) occurring to a participant should be reported to the REC that gave a 
favourable opinion of the study where in the opinion of the Chief Investigator the event was ‘related’ 
(resulted from administration of any of the research procedures) and ‘unexpected’ in relation to those 
procedures. Reports of related and unexpected SAEs should be submitted within 15 working days of the 
Chief Investigator becoming aware of the event, using the HRA report of serious adverse event form (see 
HRA website). Any adverse event considered to be related to any devices supplied by Corin shall be 
submitted to Corin via https://vigilance.coringroup.com/vigilance-form/.  
 
11. STATISTICS 
11.1. 
The Number of Participants 
The study’s aim is to determine whether the Corin OPS system reduces dislocation rate, compared to 
standard surgical technique and templating. A literature review found that the dislocation rate after THA 
was 5.0%11,17,18. A clinically significant difference of interest of 4.5% will be used in this study, meaning the 
required dislocation rate in the OPS group is <0.5%. We performed a power calculation, with α significance 
of 0.05 and power of 0.8, which gave a required sample size of 414 participants. Accounting for a dropout 
rate of 10%, this gives a total requires sample size of 460, with 230 participants in each arm.  
The first 100 participants recruited will be entered into an internal pilot study. The internal pilot study will 
study the rate of recruitment of participants and analyse whether completion of recruitment of all patients 
is feasible within our time limits. If the internal pilot study shows that completing the study is unfeasible, 
then the full trial will be terminated. The internal pilot study will allow calculation of a provisional 
dislocation rate (the primary outcome) in the control arm of the study. The rationale for this is that the 
control arm participants may have a different dislocation rate to that found in our literature review. Using 
the dislocation rate in the internal pilot study and the minimum clinically significant difference of interest, 
we will re-calculate the sample size require to fully power the full study. We expect, therefore, that the 
full study sample size may change by 5% either way from our projected sample size of 476 participants. 
However, if the size of the cohort increases by more than 5% (to above 500) we may need to re-approach 
the funder to enable us to recruit additional participants. 
The subgroup of 50 participants receiving gait analysis pre-operatively and at 12-month post-operatively 
will include 25 participants from each study arm. The sample size of 50 is of sufficient size to give detailed 
information. Analysis on a larger group is not possible due to gait laboratory capacity constraints. 
The subgroup of participants receiving a 12-month post-operative CT scan will include 50 participants from 
the OPS arm. The position of the implant compared to the planned position will be analysed. The sample 
size of 50 is of sufficient size to give detailed information. Analysis on a larger subgroup is not possible due 
to financial constraints. 

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11.2. 
Description of Statistical Methods 
The statistical analysis is the responsibility of the NDORMS OSIRIS Trial Statistician. A full statistical analysis 
plan will be written and agreed by the Trial Steering Committee before any analyses are undertaken, and 
all reporting will follow the CONSORT reporting guidelines. 
All primary analyses will follow an ‘intention to treat’ (ITT) principle, with all participants included in the 
analyses based on the treatment arm to which they were initially randomised, regardless of their 
compliance with the protocol. 
The analysis of this study will be performed after all participants have completed their 12-month post 
intervention assessment. Data will also be analysed with respect to health economics. 
The primary outcome of dislocation rate will be calculated in each group. Data will be examined for 
distribution and the most appropriate statistical test used. If the data are normally distributed, a two-
sample t-test to compare groups may be the most appropriate. Multivariate linear regression analysis will 
be used to identify differences between the treatment groups using separate two-way comparisons (best 
practice THA surgical technique and templating versus best practice THA surgical technique with OPS-
guided templating). The model will be adjusted for relevant baseline characteristics. 
11.3. 
The Level of Statistical Significance 
All hypothesis testing will be performed at the two-sided 5% level of significance.  
11.4. 
Criteria for the Termination of the Trial 
The trial will be terminated at the one year follow up for all participants, or if any serious adverse outcome 
related to use of the pelvic screw or the laser assembly system were to become apparent during the trial, 
the leading members of the trial would meet to determine the nature of the outcome and decide upon 
the need to terminate the trial. 
11.5. 
Procedure for Accounting for Missing, Unused, and Spurious Data 
Missing or spurious data will be fully investigated as to ascertain the reason. The PI will then decide 
whether the participant(s) whose data are missing should continue to be followed. All missing, unused or 
spurious data will be accounted for in any analyses 
11.6. 
Inclusion in Analysis 
All randomised participants will be included in the analyses. If a participant is unblinded, then only 
information gathered on the participant prior to unblinding will be used in the analysis. 
11.7. 
Procedures for Reporting any Deviation(s) from the Original Statistical Plan 
A full statistical analysis plan will be written and agreed by the Trial Steering Committee before any 
analyses are undertaken, and all reporting will follow the CONSORT reporting guidelines. Any deviation 
from this will be reported in the final report and accounted for in future trial planning and analysis. 

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12. DATA MANAGEMENT 
12.1. 
Access to Data 
Direct access will be granted to authorised representatives from the Sponsor, host institution and the 
regulatory authorities to permit trial-related monitoring, audits and inspections. 
12.2. 
Data Recording and Record Keeping 
Members of the trial team will be able to access the digital or paper records of patients enrolled in the trial 
for data collection. Radiological images will be downloaded from the image acquisition equipment or PACS 
onto DVDs for upload onto study computers for analysis. All personal data for patients including addresses, 
contact numbers and email addresses will be held in paper records and electronically. Data will be 
anonymised at the earliest practical point. Thenceforth the participants will be identified by a unique trial 
specific number. 
University desktop and laptop computers will be used to analyse data but they will not be used to store 
patient identifiable data. Participants will be identified by means of unique and anonymous code numbers 
within the trial database and this will be encrypted. The trial coordinator, who will be unblinded, will retain 
a list of patients, their anonymous code number, and the treatment arm they have been allocated to. They 
will be the only person with access to this list. Electronic data that contains identifiable data will be 
retained on password protected computers at the study sites and data will be backed up using encrypted 
external hard drives stored with imaging DVDs in a locked cabinet in the Botnar Research Centre (BRC). 
The BRC is an alarmed facility accessed only by authorized personnel using swipe card or proximity access 
security systems. 
If the clinical condition of a participant necessitates breaking the code, then the trial coordinator will be 
responsible for breaking the code in this situation. If they are unavailable then the surgeon who performed 
the procedure will be required to break the code. Any request to break the code, and the act of breaking 
the code, will be documented for time, date, requester, and person informed. The trial coordinator and 
surgeon who performed the procedure, who will be unblinded, will retain a list of patients, their 
anonymous code number, and the treatment arm they have been allocated to. They will be the only people 
with access to this list. In the event of a need to code-break, the trial coordinator will be responsible for 
accessing this list to determine treatment allocation and will inform the principal investigator of this.  
13. QUALITY ASSURANCE PROCEDURES 
The study may be monitored, or audited in accordance with the current approved protocol, GCP, relevant 
regulations and standard operating procedures. 
14. OTHER ETHICAL CONSIDERATIONS 
No randomized trial has been performed to investigate the efficacy of the OPS system in reducing 
dislocation rates after total hip arthroplasty. In light of this absence of evidence, we believe the best 
method to identify if the use of this system will improve outcomes for patients is a randomized controlled 
trial to compare the use of OPS in THA with conventional templating in THA. 

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In the NHS when performing total hip replacement, a consultant surgeon is able to choose which prosthetic 
femoral stem and acetabular cup to use based on their expert opinion, as long as the implants are 
approved for use in the UK. The Corin femoral stem options (MiniHip, TriFit, MetaFix and TaperFit) and 
acetabular cup (Trinity shell system) that will be used in this study are CE marked and widely used across 
the UK. A range of sizes are available to suit all anatomical morphologies. Patients will only be included in 
this study and receive the Corin implants if their surgeons approve that use of the Corin implants is 
suitable. 
The duration of the surgical procedure for participants in the OPS arm of the study is likely to be longer 
compared to routine care. This is because of the added steps required in positioning the acetabular shell 
during the operation. Based on previous experience in the use of Corin OPS for THR, the average increased 
duration of surgery is 15 minutes, from 70 minutes to 85 minutes. This increase in duration of surgery is 
within safe limits and will not place the participants at significant risk. 
The radiation exposure will be greater for all participants in the study, compared to if they underwent THR 
with routine care. The additional radiation exposure has been reviewed and risk assessed by a Consultant 
Radiologist and a Medical Physics Expert. The additional radiation dose was approved. The additional risk 
will be fully explained to patients at recruitment. 
Participation in this trial may lead to more follow-up visits than routine care in order to collect the outcome 
measurements. This may be considered an inconvenience to patients and accordingly we will make this 
clear during the consent process prior to enrolment. The more frequent visits have a potentially beneficial 
effect giving patients greater opportunities to ask any questions they may have and also to pick up any 
complications that may arise following surgery. 
14.1. 
Declaration of Helsinki 
The Investigator will ensure that this trial is conducted in accordance with the principles of the Declaration 
of Helsinki.  
14.2. 
Guidelines for Good Clinical Practice 
The Investigator will ensure that this trial is conducted in accordance with relevant regulations and with 
Good Clinical Practice. 
14.3. 
Approvals 
The protocol, informed consent form, participant information sheet and any proposed advertising material 
will be submitted to an appropriate Research Ethics Committee (REC), HRA, regulatory authorities, and 
host institutions for written approval. 
The Investigator will submit and, where necessary, obtain approval from the above parties for all 
substantial amendments to the original approved documents. 
14.4. 
Reporting 

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The CI shall submit once a year throughout the clinical trial, or on request, an Annual Progress Report to 
the REC, HRA (where required), host organisation and Sponsor.  In addition, an End of Trial notification and 
final report will be submitted to the REC, host organisation and Sponsor. 
14.5. 
Participant Confidentiality 
The trial staff will ensure that the participants’ anonymity is maintained.  The participants will be identified 
only by a participant ID number on all trial documents and any electronic database, with the exception of 
the CRF, where participant initials may be added.  All documents will be stored securely and only accessible 
by trial staff and authorised personnel. The trial will comply with the Data Protection Act, which requires 
data to be anonymised as soon as it is practical to do so. 
14.6. 
Expenses and Benefits 
Reasonable travel expenses for any visits additional to normal care will be reimbursed on production of 
receipts, or a mileage allowance provided as appropriate. 
15. FINANCE AND INSURANCE 
15.1. 
Funding 
All research facilities required are located and available at the Nuffield Orthopaedic centre site. All surgical 
facilities are available and in place, located at the sites taking part in the study. The facilities would be in 
use for the scheduled arthroplasty surgery regardless. Corin Ltd will supply all equipment and training 
required for the use of the OPS system. Corin Ltd has supplied £488,280.44 to fund the running of the trial 
for three years. If the internal pilot shows the study is unfeasible, the study will be terminated early 
pending mutual agreement from both parties. 
15.2. 
Insurance 
The University has a specialist insurance policy in place, which would operate in the event of any 
participant suffering harm as a result of their involvement in the research (Newline Underwriting 
Management Ltd, at Lloyd’s of London).  NHS indemnity operates in respect of the clinical treatment that 
is provided. 
16. PUBLICATION POLICY 
Reporting will follow the CONSORT statement protocol for reporting RCTs. The investigators will be 
involved in reviewing drafts of the manuscripts, abstracts, press releases and any other publications arising 
from the study. Authors will acknowledge the funders of the study. Authorship will be determined in 
accordance with the ICMJE guidelines and other contributors will be acknowledged. 
17. REFERENCES 
 
1 
Woolf AD, Pfleger B. Burden of major musculoskeletal conditions. Bull World Health Organ 2003; 

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Does the Corin Optimised Positioning System improve clinical outcome in total hip replacement? 
Chief Investigator: Professor Siôn Glyn-Jones 
IRAS Project Number: 216084 
 
Rec Reference Number: 17/SC/0506 
 
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Dargel J, Oppermann J, Brüggemann G-P, Eysel P. Dislocation following total hip replacement. Dtsch 
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Does the Corin Optimised Positioning System improve clinical outcome in total hip replacement? 
Chief Investigator: Professor Siôn Glyn-Jones 
IRAS Project Number: 216084 
 
Rec Reference Number: 17/SC/0506 
 
18. APPENDIX A:  TRIAL FLOW CHART 
 
 
 
 
 
 

Date and version No: 10/11/2017 v1.2 
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Protocol 1.2 
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Does the Corin Optimised Positioning System improve clinical outcome in total hip replacement? 
Chief Investigator: Professor Siôn Glyn-Jones 
IRAS Project Number: 216084 
 
Rec Reference Number: 17/SC/0506 
 
19. APPENDIX B:  SCHEDULE OF PROCEDURES 
 
Approach 
in clinic 
Consent 
visit 
Baseline 
visit 
Intervention 
3 months 
6 months 
12 months 
Explain study  
X 
X 
 
 
 
 
 
Opt-in form 
X 
 
 
 
 
 
 
Eligibility assessment  
 
X 
 
 
 
 
 
Informed consent 
 
X 
 
 
 
 
 
Collect demographics 
& medical history 
details 
 
X 
 
 
 
 
 
Clinical examination 
 
 
X 
X 
X 
X 
X 
Operative details 
recorded 
 
 
 
X 
 
 
 
CT scan 
 
 
X 
 
 
 
X* 
X-rays 
 
 
X 
 
 
 
X 
PROMs & HHS 
 
 
X 
 
X 
X 
X 
Gait analysis 
 
 
X# 
 
 
 
X# 
Health economics 
 
 
 
 
 
 
X 
Adverse events (as 
reported) 
 
 
 
X 
X 
X 
X 
*Only in a select subgroup of patients (see section 8.6) 
#Only in a select subgroup of patients (see section 8.5) 
 

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Does the Corin Optimised Positioning System improve clinical outcome in total hip replacement? 
Chief Investigator: Professor Siôn Glyn-Jones 
IRAS Project Number: 216084 
 
Rec Reference Number: 17/SC/0506 
 
20. APPENDIX C:  AMENDMENT HISTORY 
 
Amendment 
No. 
Protocol 
Version No. 
Date issued 
Author(s) 
of 
changes 
Details of Changes made