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Trial registered on ANZCTR


Trial ID
ACTRN12614000538640
Ethics application status
Not yet submitted
Date submitted
9/04/2014
Date registered
21/05/2014
Date last updated
21/05/2014
Type of registration
Prospectively registered

Titles & IDs
Public title
A prospective study evaluating joint-line changes, patient outcomes and migration after Unity Total Knee Replacement.
Scientific title
A prospective study evaluating joint-line changes, patient outcomes and migration after Total Knee Arthroplasty with the Corin Unity Total Knee System: A comparison of the Cruciate Retaining versus Posterior Stabilised Surgical Techniques
Secondary ID [1] 284407 0
Nil Known
Universal Trial Number (UTN)
U1111-1155-5029
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Osteoarthritis of the knee requiring elective Total Knee Replacement
291599 0
Rheumatoid arthritis of the knee requiring elective Total Knee Replacement 291671 0
Condition category
Condition code
Musculoskeletal 291978 291978 0 0
Osteoarthritis
Inflammatory and Immune System 292049 292049 0 0
Rheumatoid arthritis
Surgery 292050 292050 0 0
Surgical techniques

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
The Unity Total Knee System is a fixed bearing total knee replacement system that consists of a femoral component, tibial insert, tibial tray and all-polyethylene patellar component for use in primary total knee arthroplasty.

The Unity Total Knee System is provided in two variants, Cruciate Retaining (CR) and Posterior Stabilised (PS) and is intended for cemented, single use only. The system also provides augment components including femoral augments, tibial augments stem extensions, and offset connections.

The Unity Total Knee System is intended for use in skeletally mature patients, to provide increased mobility and reduce pain by replacing the damaged knee joint articulation where there is evidence of sufficient sound bone to seat and support the components.

The approximate duration of the surgical procedure of both the CR and PS surgical techniques is 60 to 90 minutes.
Intervention code [1] 289152 0
Treatment: Devices
Intervention code [2] 289153 0
Treatment: Surgery
Comparator / control treatment
The Corin Unity study is designed as a prospective, randomised study. Performance of the Unity Total Knee System will be compared to other prostheses outlined in the Australian Joint Registry and prostheses currently investigated at the International Musculoskeletal Research Institute (IMRI) site.

The surgical technique for implantation of this prosthetic system will be either through the Cruciate Retaining technique (CR) or the Posterior Stabilizing technique (PS). Patients will be evenly randomised into one of two groups which will determine the surgical technique they receive. Neither of the two surgical techniques is considered to be a study control.
Control group
Active

Outcomes
Primary outcome [1] 291881 0
The primary objective of this study is to evaluate the change in medial joint-line position (JLP) of patients implanted with the Unity Total Knee System in both flexion and extension from preoperative to six months postoperative, as measured via CT imaging assessments. A comparison of the change in JLP of patients having received the Posterior Stabilised versus the Cruciate Retaining surgical technique will be conducted.
Timepoint [1] 291881 0
CT evaluations will be conducted preoperatively and at 6 months postoperatively.
Secondary outcome [1] 307729 0
A clinical evaluation to be used will include the Knee Society Score.
Timepoint [1] 307729 0
The Knee Society Score will be assessed preoperatively and postoperatively at 6 weeks, 6 months, 1 year, 3 years and 5 years.
Secondary outcome [2] 307845 0
Clinic-based Functional Tests will be measured preoperatively and postoperativey and will include the Timed up and go test, One leg stand and the 6-minute walk test.
Timepoint [2] 307845 0
Clinic-based Functional Tests will be measured preoperatively and postoperatively at 6 weeks, 6 months and 1 year.
Secondary outcome [3] 307846 0
Radiographic evaluation of the patients’ lower limb will be conducted by way of three standardized x-ray views (14” x 17” WB PA and Lateral and Skyline), MRI, AP Long Leg x-ray and Radiostereometric Analysis (RSA).
Timepoint [3] 307846 0
PA and Lateral and Skyline x-rays will be conducted preoperatively and at 6 weeks, 6 months, 1 year, 3 years and 5 years.

An MRI will be conducted to quantify PCL state and functionality. MRIs will be taken preoperatively and at 6 months and 5 years postoperatively.

AP Long Leg x-rays will be taken preoperatively and at 6 months postoperatively in order to assess leg alignment.

RSA will be performed at discharge, 6 weeks, 6 months, 1 year, 2 years and 5 years postoperatively to measure migration of the prosthesis.
Secondary outcome [4] 308212 0
A further clinical evaluation which will be collected is the Patella Score.
Timepoint [4] 308212 0
The Patella Score will be assessed preoperatively and postoperatively at 6 weeks, 6 months, 1 year, 3 years and 5 years.
Secondary outcome [5] 308213 0
Another clinical evaluation which will be collected is the Oxford Knee Score.
Timepoint [5] 308213 0
The Oxford Knee Score will be assessed preoperatively and postoperatively at 6 weeks, 6 months, 1 year, 3 years and 5 years.
Secondary outcome [6] 308214 0
A further clinical evaluation which will be collected is the VAS for anterior knee pain.
Timepoint [6] 308214 0
The VAS for anterior knee pain will be assessed preoperatively and postoperatively at 6 weeks, 6 months, 1 year, 3 years and 5 years.
Secondary outcome [7] 308215 0
A further clinical evaluation which will be collected is the Knee injury and Osteoarthritis Outcome Score.
Timepoint [7] 308215 0
The Knee injury and Osteoarthritis Outcome Score will be assessed preoperatively and postoperatively at 6 weeks, 6 months, 1 year, 3 years and 5 years.
Secondary outcome [8] 308216 0
A further clinical evaluation which will be collected is the EuroQol-5 Dimension Health Score.
Timepoint [8] 308216 0
The EuroQol-5 Dimension Health Score will be assessed preoperatively and postoperatively at 6 weeks, 6 months, 1 year, 3 years and 5 years.

Eligibility
Key inclusion criteria
Selection of participants for this study will be in accordance with the following inclusion criteria:

1. The patient must be listed for a primary total knee replacement using the Corin Unity TKR System, according to the product ‘Instructions for Use’:

- Degenerative arthritis, rheumatoid arthritis or post-traumatic arthritis.

- Post-traumatic loss of knee joint configuration and function.

- Moderate varus, valgus, or flexion deformity in which the ligamentous structures can be returned to adequate function.

2. The patient must give signed informed consent to participate in the study.

3. The patient must be able to understand all that is expected of them and be able to comply with the study protocol.

4. Male and female patients who are skeletally mature.
Minimum age
18 Years
Maximum age
No limit
Gender
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
Exclusion criteria are in accordance with contraindications for the Unity Total Knee System.

1. Any patient with a total knee replacement not implanted with a Corin Unity TKR.

2. Any patient with severe instability secondary to advanced loss of osteochondral structure or the absence of collateral ligament integrity.

3. Any patient with a fracture of the distal femur and/or proximal tibia that cannot be stabilized by standard fracture management techniques.

4. Any patient with infection/ distant foci of infections.

5. Any patient with osteomyelitis, Osteoporosis, Osteomalacia.

6. Any patient with marked bone loss or bone resorption

7. Any patient with metabolic disorders which may impair bone formation.

8. Any patient with vascular insufficiency.

9. Any patient with muscular atrophy or neuromuscular disease.

10. Any patient with a revision total knee replacement or conversion of a Unicondylar replacement to a total knee replacement on the operative knee.

11. Any patient with fixed flexion contracture greater than 20 degrees.

12. Any patient with varus/valgus deformity greater than 10 degrees.

13. Any case not described in the inclusion criteria.

14. Any patient who cannot or will not provide signed informed consent for participation in the study.

15. Any patient whose prospects for a recovery to independent mobility would be compromised by known co-existent, medical problems.

16. Patient is female of child-bearing age and not taking contraceptive precautions.

17. Any patient currently a prisoner.

18. Any patient known to be a drug or alcohol abuser, or have a psychological disorder that could affect follow-up care or treatment outcomes.

19. Any patient currently involved in any personal injury litigation, medical-legal or worker’s compensations claims.

20. Known Posterior Cruciate Ligament (PCL) instability or injury.

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)
The anticipated enrolment of clinical study participants is 150 participants from the General Repatriation Hospital.
As per standard practice at the International Musculoskeletal Research Institute (IMRI), study investigators will authorise Clinical Research Assistants to identify patients who meet the inclusion criteria. The recruitment process will involve a review of the Orthopaedic Waiting List at the Repatriation General Hospital, with recruitment commencing following Ethics approval and SA SSA governance approval. Patient status on the waiting list is in no way effected by participation in this study.

Patients considered suitable for potential study enrolment will be contacted by the IMRI research team to ascertain their level of interest in participating in the study. Allocation is not concealed.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Prior to recruitment, the study numbers from 1 to 150 will be randomised to either the CR or PS group using Excel randomisation software. Further randomisation using Excel randomisation software will randomly select a cohort of 100 study participants (50 Cruciate Retaining and 50 Posterior Stabilising) to have RSA. After informed consent is given by the patient for inclusion into the study, the patients will be allocated a study number according to their chronological time of inclusion. This randomised number will determine which surgical technique the patient will receive, if the patient will have RSA and provide anonymous identification of the patient on study documents (or databases) from there forth.
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Parallel
Other design features
Phase
Not Applicable
Type of endpoint(s)
Safety/efficacy
Statistical methods / analysis
Selvarajah et al. (2009) evaluated the effect of joint line position in a posterior cruciate ligament-retaining, mobile bearing TKR for a single surgeon series of 76 consecutive patients at a minimum of 2.5 years post-operative. Pre-operative and post-operative weight-bearing x-rays were compared. The joint line was defined as the line through the distal aspect of the femoral condyles (femoral condyles overlying each other), where the position of the joint line is the distance from the proximal tip of the fibular to the joint line. The change in joint line position (JLP) was the difference between the pre-operative and post-operative joint line position. The average range of motion was 108.2 degrees, and no knee had a significant fixed flexion deformity. All polyethylene bearings used were 10 mm thick. The joint line position averaged 15.5 mm pre-operatively (SD = 5.6 mm) and 16.6 mm (SD = 4.6 mm) post-operatively. This was a change in joint line position of an average of +1.1 mm (SD = 4.1 mm) (P = .017). The range of variance between the pre-operative and post-operative joint line position was -11 mm to +10 mm. Figgie et al. (1986) stated that a change in joint line of eight millimetres or less represented a range of neutral alignment while Cross et al. (2013) found that 4mm change in joint line leads to mid-flexion laxity in a well-balanced knee following TKA and more recently, 2mm change in joint line has been proposed. For purposes of this study, a change in joint line of 2mm is used in the primary endpoint.

Assessment of the joint line will be completed with the knee in flexion and extension.

Primary endpoint:
The primary objective of this study is to evaluate the change in medial joint-line position (JLP) of patients implanted with the Unity Total Knee System in both flexion and extension from preoperative to six months postoperative, as measured via CT imaging assessments. A comparison of the change in JLP of patients having received the Posterior Stabilised versus the Cruciate Retaining surgical technique will be conducted.

Using a conservative estimate of increase in post-operative joint line which may have a significant impact on clinical outcomes, the primary efficacy hypothesis for this study is formulated based upon the estimate representing the proportion (or probability) of Unity devices expected to achieve (|change in JLP|) < 2.

Assumption: if change in JLP (Selvarajah, 2009) is approximately normal with mean equal to 1.1 mm and standard deviation equal to 4.1 mm, then proportion (|change in JLP|>2 mm) = 0.94.

The recommended sample size for the primary analysis group is 105 subjects before accounting for lost to follow-up.
In order to achieve this target enrolment, the number N=105 is divided by 0.85 to account for 15% potential losses-to-follow-up. Therefore, 124 subjects will be enrolled to account for loss-to-follow up.

To provide clinical data for both variants of the Unity TKR system, both cruciate retaining (CR) and posterior stabilized (PS), study subjects will randomized between the 2 groups. An oversample will be enrolled such that 75 subjects will be randomly assigned to the CR group and 75 subjects will be randomly assigned to the PS group.

Study group:
CR cohort = 75 subjects
PS cohort = 75 subjects

The analysis for the primary endpoint will evaluate a change in joint line by comparing the 6 month post-operative CT to the pre-operative CT. An increase in joint line of less than 2 mm is expected to have no impact on clinical outcomes. Results for the primary endpoint will be compared to the literature.

Secondary outcome measures include pain symptoms, improvement in general knee function, quality of life improvement, adverse events and radiographic evaluation based upon the assessments described above.

Data produced from both primary and secondary objective measures will undergo descriptive analyses where frequency, mean, median, standard deviation, minimum/maximum values and any further suitable descriptive test will be calculated. Inferential analyses to be run on both the primary and secondary objectives may include, but need not be limited to t-tests, ANOVAs, Chi-squared tests and regression models. Demographic data, along with all adverse events and radiograph results will be tabulated and summarized.

Recruitment
Recruitment status
Not yet recruiting
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)
SA

Funding & Sponsors
Funding source category [1] 289057 0
Commercial sector/Industry
Name [1] 289057 0
Corin (Australia) Ptd Ltd
Address [1] 289057 0
Corin Australia
17 Bridge Street
Pymble, NSW 2073
Australia
Country [1] 289057 0
Australia
Primary sponsor type
Other
Name
International Musculoskeletal Research Institute (IMRI)
Address
Level 1, B-Block
Repatriation General Hospital
Daws Road,
Daw Park SA- 5041
Country
Australia
Secondary sponsor category [1] 287725 0
None
Name [1] 287725 0
Address [1] 287725 0
Country [1] 287725 0

Ethics approval
Ethics application status
Not yet submitted
Ethics committee name [1] 290856 0
The Southern Adelaide Clinical Human Research Ethics Committee (SAC HREC)
Ethics committee address [1] 290856 0
Flinders Drive,
Flinders Medical Centre
Bedford Park SA 5042
Ethics committee country [1] 290856 0
Australia
Date submitted for ethics approval [1] 290856 0
28/02/2014
Approval date [1] 290856 0
Ethics approval number [1] 290856 0
92.14

Summary
Brief summary
This research project is a prospective, randomised clinical study. The primary purpose of this study is to evaluate the change in medial joint-line position (JLP) of patients implanted with the Unity Total Knee System, in both flexion and extension, from preoperative to six months postoperative. A comparison of the change in JLP of patients having received the Posterior Stabilised versus the Cruciate Retaining surgical technique will be conducted. Secondary objectives are to track clinical outcomes, functional results and imaging assessments of patients implanted with the Unity Total Knee System over a 5-year follow-up period.

The study will require 150 participants, equally randomised to receive either the Posterior Stabilised (PS) or Cruciate Retaining (CR) surgical technique. Both PS and CR techniques are reasonable standards of care employed on the basis of surgeon preference. RSA analysis will be performed on a randomised cohort 100 study participants (50 CR and 50 PS). Participants will be assessed preoperatively and postoperatively at discharge, 6 weeks, 6 months, 1 year, 2, 3 and 5 years.

All Corin Unity Study procedures adhere to the standard operating procedures at the International Musculoskeletal Research Institute Inc.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 47594 0
Dr Chris Wilson
Address 47594 0
Department of Orthopaedic Surgery,
Repatriation General Hospital,
216 Daws Rd,
Daw Park, SA 5041
Country 47594 0
Australia
Phone 47594 0
618 8275 1027
Fax 47594 0
Email 47594 0
chriswilson42@hotmail.com
Contact person for public queries
Name 47595 0
Ms Annika Theodoulou
Address 47595 0
The International Musculoskeletal Research Institute Inc.
B-Block
216 Repatriation General Hospital
Daws Road,
Daw Park SA- 5041
Country 47595 0
Australia
Phone 47595 0
618 8275 1052
Fax 47595 0
Email 47595 0
annika.theodoulou@imri.org.au
Contact person for scientific queries
Name 47596 0
Ms Annika Theodoulou
Address 47596 0
The International Musculoskeletal Research Institute Inc.
B-Block
216 Repatriation General Hospital
Daws Road,
Daw Park SA- 5041
Country 47596 0
Australia
Phone 47596 0
618 8275 1052
Fax 47596 0
Email 47596 0
annika.theodoulou@imri.org.au