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Trial registered on ANZCTR


Registration number
ACTRN12617001627347
Ethics application status
Approved
Date submitted
27/11/2017
Date registered
13/12/2017
Date last updated
13/10/2020
Date data sharing statement initially provided
27/03/2019
Type of registration
Prospectively registered

Titles & IDs
Public title
Does restoring the native alignment of the knee improve soft tissue balance during total knee replacement surgery? A randomised controlled trial
Scientific title
Does restoring the kinematic alignment of the knee improve soft tissue balance during total knee arthroplasty? A randomised controlled trial
Secondary ID [1] 293374 0
None
Universal Trial Number (UTN)
U1111-1205-2473
Trial acronym
CPAK
Linked study record
N/A

Health condition
Health condition(s) or problem(s) studied:
Knee osteoarthritis 305499 0
Rheumatoid arthritis 305763 0
Condition category
Condition code
Musculoskeletal 304750 304750 0 0
Osteoarthritis
Inflammatory and Immune System 304751 304751 0 0
Rheumatoid arthritis
Surgery 304985 304985 0 0
Surgical techniques

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Item 1. Brief name: Initial bony cuts (distal femur and proximal tibia) in routine total knee arthroplasty made according to the kinematic alignment outlined in the surgical plan
Item 2. Why: There has been a recent surge in popularity of kinematic alignment in total knee arthroplasty with a lack of evidence to support the assumed benefits. At the same time, knee ligament balance appears to be a major surgical factor towards an optimized patient outcome. This intervention aims to restore patients to their native knee alignment and ligament balance.
Item 3. What (materials): All instrumentation involved in the intervention arm are standard of care for routine total knee arthroplasty.
Item 4. What (procedure): Initial bony cuts to the distal femur and proximal tibia in the intervention group will be made according to the kinematic alignment in the surgical plan. This plan will include an aim for femoral and tibial component position relative to the mechanical axis of the bones. These cuts will be guided and validated by a full optical surgical navigation system to ensure maximum accuracy. The VERASENSE™ (OrthoSensor, USA) pressure monitoring insert will be used after the proposed alignment has been achieved, but in the intervention group, surgeons will be blinded as to the initial pressure readings. After recording the initial pressure data, surgeons will be able to view the data to allow soft tissue balancing as per standard operating techniques. Any soft tissue or bony adjustments undertaken to achieve this will be recorded.
Item 5. Who provided: Two knee arthroplasty surgeons at one hospital will perform all the surgeries. Both surgeons have extensive experience in all aspects of total knee arthroplasty.
Item 6. How: The intervention will be provided to patients undergoing routine total knee arthroplasty who have been allocated to the intervention arm preoperatively.
Item 7. Where: All interventions will be provided at St George Private Hospital, Kogarah, NSW.
Item 8. When and how much: The intervention is intra-operative.
Item 9. Tailoring: N/A
Item 10. Modifications: N/A
Item 11. Adherence/Fidelity (planned): N/A
Item 12. Adherence/Fidelity (actual): N/A. The trial has not begun yet.
Intervention code [1] 299630 0
Treatment: Surgery
Comparator / control treatment
Item 1. Brief name: Initial bony cuts (distal femur and proximal tibia) in routine total knee arthroplasty made perpendicular to mechanical axis, and an overall hip-knee-ankle angle of zero degrees
Item 2. Why: The control treatment represents the traditional mechanical alignment commonly used in total knee arthroplasty.
Item 3. What (materials): All instrumentation involved in the control arm are standard of care for routine total knee arthroplasty.
Item 4. What (procedure): The surgeon will perform the initial bony cuts using the same full optical surgical navigation system, this time aiming for tibial and femoral component positions perpendicular to the mechanical axis of the bone and an overall hip-knee-angle of zero degrees. The VERASENSE™ (OrthoSensor, USA) pressure monitoring insert will be used after this mechanical alignment has been achieved, and in the control group, surgeons will be able to view the data to allow soft tissue balancing as per standard operating techniques.
Item 5. Who provided: Two knee arthroplasty surgeons at one hospital will perform all the surgeries. Both surgeons have extensive experience in all aspects of total knee arthroplasty.
Item 6. How: The control treatment will be provided to patients undergoing routine total knee arthroplasty who have been allocated to the control arm preoperatively.
Item 7. Where: All interventions will be provided at St George Private Hospital, Kogarah, NSW.
Item 8. When and how much: The control treatment is intra-operative.
Item 9. Tailoring: N/A
Item 10. Modifications: N/A
Item 11. Adherence/Fidelity (planned): N/A
Item 12. Adherence/Fidelity (actual): N/A. The trial has not begun yet.
Control group
Active

Outcomes
Primary outcome [1] 303974 0
Quantification of soft-tissue balance using the VERASENSE™ (OrthoSensor, USA) pressure monitoring insert. The primary outcome is measurement of the initial intraoperative difference in pressure between the medial and lateral compartments at 10 degrees of flexion.
Timepoint [1] 303974 0
Intraoperative
Secondary outcome [1] 340584 0
Knee pain, symptoms and function using the Knee Osteoarthritis Outcome Score (KOOS)
Timepoint [1] 340584 0
Pre-op, 6 months, 1 year, 2 years
Secondary outcome [2] 340586 0
Patient's overall awareness of knee joint as measured by the Forgotten Joint Score (FJS-12)
Timepoint [2] 340586 0
Pre-op, 1 year, 2 years
Secondary outcome [3] 340587 0
Quality of life using the Euro Quality of Life (EQ5D-5L) score
Timepoint [3] 340587 0
Pre-op, 6 months, 2 years
Secondary outcome [4] 340588 0
ACORN (Arthroplasty Clinical Outcomes Registry) Satisfaction and Success score
Timepoint [4] 340588 0
6 months, 2 years

Eligibility
Key inclusion criteria
Patients who meet the indications for primary total knee replacement using the Smith & Nephew posterior-stabilized total knee arthroplasty system
Patients diagnosed with idiopathic osteoarthritis, rheumatoid arthritis or post-traumatic osteoarthritis
Minimum age
20 Years
Maximum age
80 Years
Sex
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
Revision knee replacement
Previous insufficiency fracture
Prior Grade 3 posterior cruciate ligament, posterolateral corner or lateral collateral ligament injury
Prior medial collateral ligament injury if it still a Grade 2 or Grade 3 laxity
Prior femoral, tibial or patellofemoral osteotomies
Other prior knee surgery (except arthroscopic meniscectomy or anterior cruciate ligament reconstruction)
Ipsilateral foot, ankle or hip arthritis
Preoperative range of motion <90 degrees and flexion contracture >20 degrees
Pregnant female, or planning on becoming pregnant during study follow-up period
Mental condition that may interfere with capacity to fulfil study requirements
Inability to provide fully informed consent due to cognitive incapacity or English language deficiency

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)
Allocation by contacting the holder of the allocation schedule, who will be at central administration site. The surgeon who determines patient eligibility for inclusion in the trial will not be aware to which group the subject will be allocated.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomization using a computerized randomisation table
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?

The people administering the treatment/s

Intervention assignment
Parallel
Other design features
Phase
Not Applicable
Type of endpoint/s
Efficacy
Statistical methods / analysis
The senior authors have recorded the initial and final intra-compartment pressures of 280 consecutive TKAs using the Verasense device. The mean initial pressure delta at 10 degrees of flexion was 30psi (SD 30psi). The Verasense manufacturer recommends a pressure delta of less than 15psi in order for the knee to be considered balanced. Using a 5% significance and an 80% power to detect a difference of 15psi, a sample size of 125 will be required. Because the primary outcome measure is obtained intraoperatively, loss to follow-up will not be significant. Therefore, 65 patients will be randomized into each group, for a total of 130 patients overall.
Normality of data distribution will be assessed, and a Student's t-test will be used to compare differences in means with continuous variables. The chi-squared test and Fisher's exact test will be used for categorical data analysis as appropriate.
Intention-to-treat analysis will be performed in the primary analysis. In addition, a per-protocol analysis that includes participants according to treatment received will be used as a secondary analysis.
Analysis of secondary outcomes will include mixed model analyses comparing secondary outcomes between time points.
If greater than 20% of data are missing from the randomized sample, the missing data will be imputed. However, serious attempts will be made to minimise missing data by contacting patients directly by phone or mail/email follow-up.

Recruitment
Recruitment status
Active, not recruiting
Date of first participant enrolment
Anticipated
1/02/2018
Actual
26/02/2018
Date of last participant enrolment
Anticipated
1/08/2018
Actual
8/08/2018
Date of last data collection
Anticipated
1/11/2020
Actual
Sample size
Target
130
Accrual to date
Final
128
Recruitment in Australia
Recruitment state(s)
NSW
Recruitment hospital [1] 9408 0
St George Private Hospital - Kogarah
Recruitment postcode(s) [1] 18110 0
2217 - Kogarah

Funding & Sponsors
Funding source category [1] 297999 0
Self funded/Unfunded
Name [1] 297999 0
Dr Samuel Macdessi
Country [1] 297999 0
Australia
Primary sponsor type
Individual
Name
Dr Samuel Macdessi
Address
Sydney Knee Specialists
Suite 8, Level 3
19 Kensington Street
Kogarah, NSW 2217
Country
Australia
Secondary sponsor category [1] 297064 0
None
Name [1] 297064 0
Address [1] 297064 0
Country [1] 297064 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 299037 0
Bellberry Human Research Ethics Committee
Ethics committee address [1] 299037 0
129 Glen Osmond Road
Eastwood South Australia
5063
Ethics committee country [1] 299037 0
Australia
Date submitted for ethics approval [1] 299037 0
06/12/2017
Approval date [1] 299037 0
16/01/2018
Ethics approval number [1] 299037 0
2017-12-911

Summary
Brief summary
There has been a surge in popularity of so-called "kinematic" alignment in total knee arthroplasty, with a relative lack of evidence to support the claimed benefits. At the same time, knee ligament balance does appear to be a major surgical factor for an optimised patient outcome. For this reason, a study comparing the balance achieved with methods that restore the native coronal plane alignment of the knee compared to mechanical alignment is required to provide further research in this are.
The aim of this study is to determine whether ligament balance is more readily achieved by restoring the native coronal plane alignment versus traditional methods. The results of this trial will aim to inform future clinical practice internationally with regard to soft tissue balance and kinematic alignment in total arthroplasty surgery.
The hypothesis of this trial is that knees aligned to restore a patient's original anatomy will be more balanced compared to those aligned with a neutral mechanical axis and horizontal joint line.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 79070 0
Dr Samuel Macdessi
Address 79070 0
Sydney Knee Specialists
Suite 8, Level 3
19 Kensington Street
Kogarah, NSW 2217
Country 79070 0
Australia
Phone 79070 0
+61 2 8307 0333
Fax 79070 0
+61 2 8307 0334
Email 79070 0
[email protected]
Contact person for public queries
Name 79071 0
Jil Wood
Address 79071 0
Sydney Knee Specialists
Suite 8, Level 3
19 Kensington Street
Kogarah, NSW 2217
Country 79071 0
Australia
Phone 79071 0
+61 2 8307 0333
Fax 79071 0
+61 2 8307 0334
Email 79071 0
[email protected]
Contact person for scientific queries
Name 79072 0
Samuel Macdessi
Address 79072 0
Sydney Knee Specialists
Suite 8, Level 3
19 Kensington Street
Kogarah, NSW 2217
Country 79072 0
Australia
Phone 79072 0
+61 2 8307 0333
Fax 79072 0
+61 2 8307 0334
Email 79072 0
[email protected]

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
Yes
What data in particular will be shared?
Individual participant data underlying published results, after de-identification
When will data be available (start and end dates)?
Beginning 6 months after publication and no end date determined
Available to whom?
Case-by-case basis at the discretion of Primary Investigator
Available for what types of analyses?
Systematic review, including IPD meta-analyses
How or where can data be obtained?
Access subject to approvals by Principal Investigator with requirement to sign data access agreement


What supporting documents are/will be available?

Doc. No.TypeCitationLinkEmailOther DetailsAttachment
246Study protocol    374003-(Uploaded-21-06-2019-12-12-26)-Study-related document.pdf



Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
SourceTitleYear of PublicationDOI
EmbaseRestoring the constitutional alignment with a restrictive kinematic protocol improves quantitative soft-tissue balance in total knee arthroplasty: A randomized controlled trial.2020https://dx.doi.org/10.1302/0301-620X.102B1.BJJ-2019-0674.R2
EmbaseCoronal Plane Alignment of the Knee (CPAK) classification a new system for describing knee phenotypes.2021https://dx.doi.org/10.1302/0301-620X.103B2.BJJ-2020-1050.R1
N.B. These documents automatically identified may not have been verified by the study sponsor.