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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Prospectively registered

Titles & IDs
Public title
Oxford Unicompartment Knee replacement versus total knee replacement: a randomised controlled trial
Scientific title
Functional outcomes of arthroplasty for medial compartment osteoarthritis of the knee: a randomised controlled trial of Oxford unicompartmental arthroplasty versus total knee arthroplasty
Secondary ID [1] 284928 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Medial compartment osteoarthritis of the knee 292402 0
Condition category
Condition code
Musculoskeletal 292721 292721 0 0
Surgery 292741 292741 0 0
Surgical techniques

Study type
Description of intervention(s) / exposure
Uncemented Oxford Medial Unicompartmental knee replacement involves replacement of the arthritic medial compartment of the knee with an uncemented metal tray on the medial tibial plateau, an uncemented metal replacement of the medial femoral condylar articular cartilage, and a layer of mobile polyethylene inserted between the 2 components. The duration of the operation will vary, but will be in the vicinity of 60 minutes.
Intervention code [1] 289752 0
Treatment: Surgery
Intervention code [2] 289753 0
Treatment: Devices
Comparator / control treatment
Total knee joint replacement with patellar resurfacing involves removal of the cartilage surfaces of the femur and the tibia at the knee, and their replacement with metal, cemented to bone, and a layer of polyethylene in between. This operation is the most commonly used procedure for arthritis of the knee, and is the standard of care. The duration of the operation is typically about 80 minutes.
Control group

Primary outcome [1] 292562 0
Knee function as assessed by the Oxford Knee Score
Timepoint [1] 292562 0
1 year
Primary outcome [2] 292563 0
Revision operation, as recorded on the New Zealand Joint Registry (which records greater than 95% of arthroplasty operations performed in New Zealand), and by contact with patients.
Timepoint [2] 292563 0
10 years
Secondary outcome [1] 309227 0
Knee pain as assessed by Visual Analogue Pain Score
Timepoint [1] 309227 0
1 year
Secondary outcome [2] 309228 0
Range of Motion as measured by a goniometer.
Timepoint [2] 309228 0
1 year

Key inclusion criteria
Anteromedial osteoarthritis of the knee, intact ACL, preservation of full thickness lateral compartment cartilage on valgus stress XR, correctable intra-articular varus, flexion deformity less than 15 degrees.
Minimum age
40 Years
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Inflammatory arthritis, ACL deficiency, MCL deficiency, lateral compartment OA, bone on bone lateral patellofemoral OA + lateral patellar subluxation

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 evaluated in clinic for anteromedial knee osteoarthritis meeting the above criteria will be provided with verbal and written information about the study, and offered participation. Patients who wish to enrol in the study will be asked to sign a consent form. On the day of surgery a sealed envelope will be opened allocating patients to either unicompartmental knee arthroplasty or total knee arthroplasty. The patient will not be informed of their allocation, and a standardised skin incision will be used for both patient groups.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Block randomisation by gender; computerised sequence generation.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s

The people assessing the outcomes
Intervention assignment
Other design features
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
100 patients are required to allow 18 patients to drop out, leaving 82 patients available to test the hypothesis of a 5 point Oxford Knee Score difference between Oxford unicompartmental knee replacement and total knee replacement. The statistical tests proposed are 2 sample, unpaired 2-tailed T tests.

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] 6198 0
New Zealand
State/province [1] 6198 0

Funding & Sponsors
Funding source category [1] 289555 0
Name [1] 289555 0
Northland DHB
Address [1] 289555 0
Private Bag 9742
Whangarei 0148
Country [1] 289555 0
New Zealand
Primary sponsor type
Jonathan Manson
Northland DHB
Private Bag 9742
Whangarei 0148
New Zealand
New Zealand
Secondary sponsor category [1] 288237 0
Name [1] 288237 0
Marc Hirner
Address [1] 288237 0
Northland DHB
Private Bag 9742
Whangarei 0148
New Zealand
Country [1] 288237 0
New Zealand

Ethics approval
Ethics application status
Ethics committee name [1] 291294 0
Health and Disability Ethics Committees
Ethics committee address [1] 291294 0
Northern Regional A
Ministry of Health
Number 1 The Terrace
PO Box 5013
Wellington 6011
Ethics committee country [1] 291294 0
New Zealand
Date submitted for ethics approval [1] 291294 0
Approval date [1] 291294 0
Ethics approval number [1] 291294 0

Brief summary
Arthritis of the inner part of the knee is common. The most commonly used surgical treatment for this condition is total knee joint replacement. This is effective, however a knee replacement is inferior in function to the non-arthritic knee. An alternative to total knee replacement is replacement of the inner part of the knee only, thus preserving the non-arthritic parts of the knee (termed a unicompartmental replacement). Possible advantages of this include more normal motion and feeling of the knee after surgery. Possible disadvantages include durability inferior to total knee replacement. There have been few good studies comparing the 2 alternatives. This study aims to compare patient satisfaction and durability of unicompartmental knee replacement and total knee replacement.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 49722 0
Mr Jonathan Manson
Address 49722 0
Northland DHB
Private Bag 9742
Whangarei 0148
Country 49722 0
New Zealand
Phone 49722 0
+64 21 871 934
Fax 49722 0
Email 49722 0
Contact person for public queries
Name 49723 0
Mr Jonathan Manson
Address 49723 0
Northland DHB
Private Bag 9742
Whangarei 0148
Country 49723 0
New Zealand
Phone 49723 0
+64 21 871 934
Fax 49723 0
Email 49723 0
Contact person for scientific queries
Name 49724 0
Mr Jonathan Manson
Address 49724 0
Northland DHB
Private Bag 9742
Whangarei 0148
Country 49724 0
New Zealand
Phone 49724 0
+64 21 871 934
Fax 49724 0
Email 49724 0

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