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Trial registered on ANZCTR


Registration number
ACTRN12613000516785
Ethics application status
Approved
Date submitted
2/05/2013
Date registered
9/05/2013
Date last updated
9/05/2013
Type of registration
Retrospectively registered

Titles & IDs
Public title
The Use of Navigation to Achieve Soft Tissue Balance in Total Knee Arthroplasty – A Randomised Clinical Study
Scientific title
The Use of Navigation to Achieve Soft Tissue Balance in Total Knee Arthroplasty – A Randomised Clinical Study
Secondary ID [1] 282429 0
none
Universal Trial Number (UTN)
U1111-1142-5684
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
knee arthropathy 289037 0
Condition category
Condition code
Musculoskeletal 289377 289377 0 0
Osteoarthritis
Surgery 289419 289419 0 0
Surgical techniques

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
All patients receive a Triathlon posterior stabilised, fixed bearing total knee replacement (Stryker Orthopedics, Mahwah, NJ) inserted via a standardised medial para-patellar approach. In the navigated group, initial gaps, at 135N of tension provided by the tensiometer, are recorded after the tibial cut at 90 degrees flexion and full extension. The Stryker version 4.0 software is able to calculate the size of the femoral component after registration of the epicondyles and registration of the bony morphology of the anterior and posterior femoral condyles. Based on the initial gap measurements, the surgeon has a number of options to equilibrate the flexion and extension gaps. These include downsizing the femoral prosthesis or modifying the position of the femoral prosthesis in the anteroposterior or proximodistal planes. The software uses algorithms that take a mean value of the registered femoral transepicondylar axis and the registered femoral anteroposterior axis (Whiteside’s line) to determine axial rotation of the femur. The surgeon aims for the femoral bony cut to have a value of 0+/-2 degrees external rotation based on the software measurement. After the femoral cuts, the gaps at 135N are measured again. The surgeon then makes further soft tissue releases as necessary to try and equalise the mediolateral gaps to within 2mm of each other. Final gap measurements (without the trial components in place) are recorded once again at 135N of tension. 135N was chosen as the tension force as it was felt that this level of tension produced sufficient strain to overcome any laxity in the soft tissues to allow reliable measurement of gaps.
The duration of this procedure is approximately 80 minutes.
Intervention code [1] 287077 0
Treatment: Devices
Intervention code [2] 287110 0
Treatment: Surgery
Comparator / control treatment
In the non-navigated group, a standard total knee replacement procedure is carried out without the use of navigation (other than for data recording purposes). When the surgeon is satisfied by means of ‘feel’ that he has achieved a balanced knee arthroplasty, then the joint gaps are recorded (without the trial components in place) at 90 degrees flexion and at full extension. Measurements are recorded by an unscrubbed assistant using the navigation software with the navigation screen hidden from the surgeon. All measurements are carried out with a fixed tension of 135 Newtons provided by the tensiometer across the joint.
The duration of this procedure is approximately 80 minutes.
Control group
Active

Outcomes
Primary outcome [1] 289487 0
Final gap measurements (without the trial components in place) were recorded via the navigation software at 135N of tension. Tension was applied and maintained by the tensionometer. Final readings were taken from the navigation software which is used in both groups for this purpose. In the non-navigated group, this information is used purely for data recording as no figures are fed back to the surgeon. Gaps (in millimetres) measured are mediolateral difference in full extension and 90 degrees flexion and difference in flexion and extension gap.
Timepoint [1] 289487 0
intra-operatively
Secondary outcome [1] 302601 0
In a similar way, the accuracy of bony cuts in terms of coronal plane alignment in the femur and tibia and femoral rotation is recorded in both groups via the navigation software. Measurements (degrees) are recorded for resection of the distal femur and proximal tibia as well as femoral rotation.
Timepoint [1] 302601 0
intra-operatively
Secondary outcome [2] 302602 0
Final overall limb alignment is also measured via the navigation software in both groups
Timepoint [2] 302602 0
intra-operatively
Secondary outcome [3] 302603 0
Initial and final on table range of motion are also recorded via the navigation software.
Timepoint [3] 302603 0
intra-operatively
Secondary outcome [4] 302677 0
Outcome scores for pain, function and disability will be recorded pre-operatively and again at routine review at 6 weeks, 6 months and 5 years post surgery using the Knee Society Score, Oxford knee score, SF-12 and WOMAC.
Timepoint [4] 302677 0
6 weeks, 6 months and 5 years post-operatively at routine review

Eligibility
Key inclusion criteria
all patients presenting for primary total knee replacement
Minimum age
18 Years
Maximum age
No limit
Gender
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
previous bony surgery on the operated knee

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Patients provided with information sheets and informed consent obtained to enter this study at the time of being listed for the procedure. Following randomisation, allocations stored in theatre by means of envelopes allocating patients to either a non-navigated or navigated group. Envelopes were opened sequentially in theatre prior to the incision being made.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Randomisation was performed by a statistician using the Sampsize program with a block size of 4 and allocation ratio of 1:1.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s


The people analysing the results/data
Intervention assignment
Parallel
Other design features
Phase
Not Applicable
Type of endpoint(s)
Efficacy
Statistical methods / analysis
Data will be analysed with either parametric or non-parametric methods according to data type after normality testing. Levene's test will be used to examine homogeneity of variance.
Power analysis indicates that with 80% power, 5% significance level and a standardised difference of 1.0, a minimum of 17 patients are needed in each group. To ensure this minimum requirement was met, we aimed for 20 knees per group.

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
QLD
Recruitment hospital [1] 959 0
Holy Spirit Northside - Chermside
Recruitment hospital [2] 960 0
The Prince Charles Hospital - Chermside
Recruitment postcode(s) [1] 6814 0
4032 - Chermside

Funding & Sponsors
Funding source category [1] 287205 0
Self funded/Unfunded
Name [1] 287205 0
Address [1] 287205 0
Country [1] 287205 0
Primary sponsor type
Individual
Name
Dr Hugh English
Address
Brisbane Orthopaedic Specialist Services
Holy Spirit Northside Hospital
Rode Road
Chermside
QLD 4032
Country
Australia
Secondary sponsor category [1] 285968 0
None
Name [1] 285968 0
Address [1] 285968 0
Country [1] 285968 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 289198 0
St Vincent's and Holy Spirit Health HREC
Ethics committee address [1] 289198 0
Holy Spirit Northside Hospital
Rode Road
Chermside
QLD 4032
Ethics committee country [1] 289198 0
Australia
Date submitted for ethics approval [1] 289198 0
Approval date [1] 289198 0
05/08/2008
Ethics approval number [1] 289198 0
EC00324
Ethics committee name [2] 289199 0
The Prince Charles Hospital Health Service District HREC
Ethics committee address [2] 289199 0
The Prince Charles Hospital
Rode Road
Chermside
QLD 4032
Ethics committee country [2] 289199 0
Australia
Date submitted for ethics approval [2] 289199 0
Approval date [2] 289199 0
05/08/2008
Ethics approval number [2] 289199 0
EC00168

Summary
Brief summary
In this clinical study we aim to assess the difference, if any, in intra-operative soft tissue balancing in computer navigated and conventional total knee replacement (TKR). Computer navigated TKRs have been shown to produce better alignment of the components compared to conventional TKR. Whether there is any long term advantage of computer navigated TKR in terms of function and durability and patient satisfaction is as yet not proven.
In this prospective, randomised, patient blinded study, we shall measure the ligament balancing in both groups intra-operatively. This will be done using a tensiometer instrument. There is no morbidity associated with the use of this device which gives an instantaneous reading.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 39722 0
Dr Hugh English
Address 39722 0
Brisbane Orthopaedic Specialist Services
Holy Spirit Northside Hospital
Rode Road
Chermside
QLD 4032
Country 39722 0
Australia
Phone 39722 0
+61 1300 436454
Fax 39722 0
Email 39722 0
hugh@boss.net
Contact person for public queries
Name 39723 0
Dr Sarah Whitehouse
Address 39723 0
The Prince Charles Hospital
Rode Road
Chermside
QLD 4032
Country 39723 0
Australia
Phone 39723 0
+61 07 3139 6672
Fax 39723 0
Email 39723 0
s.whitehouse@qut.edu.au
Contact person for scientific queries
Name 39724 0
Dr Sarah Whitehouse
Address 39724 0
The Prince Charles Hospital
Rode Road
Chermside
QLD 4032
Country 39724 0
Australia
Phone 39724 0
+61 07 3139 6672
Fax 39724 0
Email 39724 0
s.whitehouse@qut.edu.au

No information has been provided regarding IPD availability
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary