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Trial registered on ANZCTR

Registration number
Ethics application status
Not yet submitted
Date submitted
Date registered
Date last updated
Type of registration
Prospectively registered

Titles & IDs
Public title
MRI based computer navigation of total hip replacement
Scientific title
Total hip replacement: MRI navigation
Assessment of acetabular component position with and without MRI navigation
Secondary ID [1] 279967 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Osteoarthritis of hip joints 285826 0
Condition category
Condition code
Musculoskeletal 286006 286006 0 0

Study type
Description of intervention(s) / exposure
Navigation of hip joint replacement based on MRI preop findings. Follow up results with CT scan
A standard MRI scan of the hip was used preoperatively to investigate the patient's hip anatomy in order to design the navigation tool specific to each patient. This takes approximately 30 minutes over one day. One scan is required before the operation for each patient.
A CT scan of the pelvis is obtained post-operatively to assess the position of the acetabular component and this is to be compared between the MRI navigation group and the standard free hand group. This takes approximately 30 minutes over one day. One scan is required for each patient.
Intervention code [1] 284244 0
Treatment: Surgery
Intervention code [2] 284304 0
Early detection / Screening
Intervention code [3] 284305 0
Treatment: Devices
Comparator / control treatment
Standard free-hand technique versus MRI based navigation

The standard free hand technique has been used in every single operation in New Zealand and mostly worldwide. This refers to implantation of the acetabular prosthesis without any computer navigation but simply judged by the surgeon during the procedure. It has been used since the hip joint replacement has first been introduced. For the purpose of the study some patients will be randomly allocated to this free hand group. Essentially they will received the same procedure as the standard treatment used currently in New Zealand. The control technique takes an average of one hour in our hospital to perform. The current practice of the control technique in hip joint replacement occurs on average once a day in our hospital.
Control group

Primary outcome [1] 286497 0
Position of acetabular cup based on CT scan of the pelvis post op
Timepoint [1] 286497 0
1 week
Secondary outcome [1] 296023 0
Complications of MRI based navigation technique
The MRI navigation tool is a pilot study. The main different feature of this navigation is the use of MRI scan prior to surgery. MRI scan is a safe procedure without any harm to the patients.
During surgery the navigation will use a cutting block to fit into the specific patient's pelvis and the block secured wires into the pelvis. This has been safely applied oversea without any complications clinically. However potential complications such as fracture and infection associated with this can be assessed with CT scan following surgery and subsequent follow up of patient's progress at outpatient clinic. Appropriate blood tests will be obtained if there is a clinical suspicion of infection.
Timepoint [1] 296023 0
6 months

Key inclusion criteria
Osteoarthritis of hip joint
Minimum age
50 Years
Maximum age
100 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
People who do not consent to the trial
People who are unable to undero MRI scan

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Patients attending orthopaedic outpatient clinic for consultation of osteoarthritis of their hips
Information sheet will be given by the consultant surgeon
Details of the study will be discussed
Patient's consent will be respected
Opaque envelopes containing either standard free hand or MRI navigation will be used to randomised patients at the initial consultation after consent. This will be randomly shuffled and withdrawn
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation by using a randomisation table created by computer software (i.e computerised sequence generation)
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?

Intervention assignment
Other design features
Study will be finished if the navigation group has high complication rate
Study will be finished if the navigation group shows early superior results than standard free hand group
Phase 1 / Phase 2
Type of endpoint(s)
Statistical methods / analysis

Recruitment status
Not yet recruiting
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment outside Australia
Country [1] 4123 0
New Zealand
State/province [1] 4123 0

Funding & Sponsors
Funding source category [1] 284693 0
Name [1] 284693 0
Northland District health board
Address [1] 284693 0
Whangarei Hospital
Maunu Road, Private Bag 9742,
Whangarei 0148
Country [1] 284693 0
New Zealand
Primary sponsor type
Northland District health board
Whangarei Hospital
Maunu Road, Private Bag 9742,
Whangarei 0148
New Zealand
Secondary sponsor category [1] 283594 0
Name [1] 283594 0
Address [1] 283594 0
Country [1] 283594 0
New Zealand
Secondary sponsor category [2] 283648 0
Name [2] 283648 0
Address [2] 283648 0
Country [2] 283648 0

Ethics approval
Ethics application status
Not yet submitted
Ethics committee name [1] 286691 0
Northern X ethics Committee
Ethics committee address [1] 286691 0
Private Bag 92-522, Wellesley St
Auckland 1141
Ethics committee country [1] 286691 0
New Zealand
Date submitted for ethics approval [1] 286691 0
Approval date [1] 286691 0
Ethics approval number [1] 286691 0

Brief summary
MRI computer navigation aims to improve the acetabular cup placement of the prosthesis in the pelvis. This will influence the risk of complications and survivorship of the implant. Current free hand technique leads to an excessive high percentage of position outside the standardised safe zone. The study is to investigate the position of prosthesis of acetabular cup with the MRI based navigation.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 33761 0
Address 33761 0
Country 33761 0
Phone 33761 0
Fax 33761 0
Email 33761 0
Contact person for public queries
Name 17008 0
Dr. Justin Chou
Address 17008 0
Whangarei Hospital
Maunu Road, Private Bag 9742, Whangarei 0148
Country 17008 0
New Zealand
Phone 17008 0
00 64 9 4304100
Fax 17008 0
Email 17008 0
Contact person for scientific queries
Name 7936 0
Dr. Justin Chou
Address 7936 0
Whangarei Hospital
Maunu Road, Private Bag 9742, Whangarei 0148
Country 7936 0
New Zealand
Phone 7936 0
00 64 9 4304100
Fax 7936 0
Email 7936 0

No information has been provided regarding IPD availability
Summary results
No Results