ANZCTR - Registration

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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]

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

Rheumatoid arthritis

Condition category

Condition code

Musculoskeletal

Osteoarthritis

Inflammatory and Immune System

Rheumatoid arthritis

Surgery

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]

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]

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]

Intraoperative

Secondary outcome [1]

Knee pain, symptoms and function using the Knee Osteoarthritis Outcome Score (KOOS)

Timepoint [1]

Pre-op, 6 months, 1 year, 2 years

Secondary outcome [2]

Patient's overall awareness of knee joint as measured by the Forgotten Joint Score (FJS-12)

Timepoint [2]

Pre-op, 1 year, 2 years

Secondary outcome [3]

Quality of life using the Euro Quality of Life (EQ5D-5L) score

Timepoint [3]

Pre-op, 6 months, 2 years

Secondary outcome [4]

ACORN (Arthroplasty Clinical Outcomes Registry) Satisfaction and Success score

Timepoint [4]

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?

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]

St George Private Hospital - Kogarah

Recruitment postcode(s) [1]

2217 - Kogarah

Funding & Sponsors

Funding source category [1]

Self funded/Unfunded

Name [1]

Dr Samuel Macdessi

Address [1]

Sydney Knee Specialists
Suite 8, Level 3
19 Kensington Street
Kogarah, NSW 2217

Country [1]

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]

None

Name [1]

Address [1]

Country [1]

Ethics approval

Ethics application status

Approved

Ethics committee name [1]

Bellberry Human Research Ethics Committee

Ethics committee address [1]

129 Glen Osmond Road 
Eastwood South Australia 
5063

Ethics committee country [1]

Australia

Date submitted for ethics approval [1]

06/12/2017

Approval date [1]

16/01/2018

Ethics approval number [1]

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

Dr Samuel Macdessi

Address

Sydney Knee Specialists
Suite 8, Level 3
19 Kensington Street
Kogarah, NSW 2217

Country

Australia

Phone

+61 2 8307 0333

Fax

+61 2 8307 0334

[email protected]

Contact person for public queries

Name

Jil Wood

Address

Sydney Knee Specialists
Suite 8, Level 3
19 Kensington Street
Kogarah, NSW 2217

Country

Australia

Phone

+61 2 8307 0333

Fax

+61 2 8307 0334

[email protected]

Contact person for scientific queries

Name

Samuel Macdessi

Address

Sydney Knee Specialists
Suite 8, Level 3
19 Kensington Street
Kogarah, NSW 2217

Country

Australia

Phone

+61 2 8307 0333

Fax

+61 2 8307 0334

[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.	Type	Citation	Link	Email	Other Details	Attachment
246	Study 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

Source	Title	Year of Publication	DOI
Embase	Restoring the constitutional alignment with a restrictive kinematic protocol improves quantitative soft-tissue balance in total knee arthroplasty: A randomized controlled trial.	2020	https://dx.doi.org/10.1302/0301-620X.102B1.BJJ-2019-0674.R2
Embase	Coronal Plane Alignment of the Knee (CPAK) classification a new system for describing knee phenotypes.	2021	https://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.

Trial Review

Documents added manually

Documents added automatically