Arthroplasty, Replacement, Knee, Total Knee Replacement
Conditions
Brief summary
The goal of this clinical trial is to compare two types of polyethylene (Stryker Orthopaedics N2Vac and their X3 polyethylene) prostheses that are used in total knee replacements. The primary outcome will analyze whether or not prostheses require a revision surgery 10 years post knee replacement. Other outcomes such as reoperation rate, complications, radiographic results, and clinical outcomes will be collected. It is hypothesized that X3 would perform equally well to N2Vac at 10 years.
Detailed description
This is a prospective, randomized and blinded clinical trial. Participants will be assessed pre-operatively and post-operatively at three months and two, five, seven and ten years. The primary aim of the study is to compare the survivorship of two types of polyethylene (conventional N2Vac and highly cross-linked X3, both FDA approved via 510k clearance) used in a fixed-bearing total knee system in patients undergoing cemented total knee arthroplasty. Specifically, the primary endpoint will be the revision rate at ten years. These results will be measured through radiographs at each post-operative interval with an independent radiograph review being performed after all patients have reached 7 and 10 year follow-up. Secondary results will also be collected and will focus on disease-specific (Knee Society Scores), global (SF-12), and outcome measures. Radiographic results consisting of standing anteroposterior, lateral and Merchant views of the surgical knee will be recorded and analyzed. Completion of the initial investigation will occur at the 10-year interval after the last enrolled patient.
Interventions
DEVICEX3 Polyethylene
Highly cross-linked polyethylene (HXLPE).
DEVICEN2Vac Polyethylene
Ultra-high-molecular-weight polyethylene (UHMWPE).
Sponsors
Stryker Orthopaedics
Mayo Clinic
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
SINGLE (Subject)
Eligibility
Sex/Gender
ALL
Age
21 Years to 85 Years
Healthy volunteers
No
Inclusion criteria
1. Subjects willing to sign the informed consent. 2. Subjects able to comply with follow-up requirements including post-operative weight bearing restrictions and self-evaluations. 3. Male and non-pregnant female subjects ages 21-85 years of age at the time of surgery. 4. Subjects requiring a primary total knee replacement. 5. Subjects with a diagnosis of osteoarthritis (OA), traumatic arthritis (TA), or avascular necrosis (AVN). 6. Subjects with intact collateral ligaments as determined by the surgeon investigator.
Exclusion criteria
1. Subjects with inflammatory arthritis. 2. Subjects with a history of total or unicompartmental reconstruction of the affected joint. 3. Subjects that have had a high tibial osteotomy or femoral osteotomy. 4. Subjects with neuromuscular or neurosensory deficiency, which would limit the ability to assess the performance of the device. 5. Subjects with a systemic or metabolic disorder leading to progressive bone deterioration. 6. Subjects that are immunologically compromised, or receiving chronic steroids (\>30 days). 7. Subjects bone stock is compromised by disease or infection that cannot provide adequate support and/or fixation to the prosthesis. 8. Subjects with knee fusion to the affected joint. 9. Subjects with an active or suspected latent infection in or about the knee joint. 10. Subjects that are prisoners.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Prosthesis Survivorship Free of Revision | From operation to 10 years post-operative | The survival of prostheses free of revision 10 years post operation. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Prosthesis Survivorship Free of Reoperation | From operation to 10 years post-operative | The survival of prostheses free of reoperation 10 years post operation. |
| Prosthesis Survivorship Free of Complications | From operation to 10 years post-operative | The survival of prostheses free of related complications (non-operative) 10 years post operation. |
| Knee Society Score (KSS): Function | Pre-operative (baseline) and 10-years post-operative | The Function KSS evaluates the walking distance and the act of climbing and descending stairs. The scale ranges between 0-100. The maximum score of 100 points is attributed to the individual capable of walking unlimited distances without walking aids, and of climbing and descending stairs normally. Deductions are made for the use of canes, crutches or walking frame. Higher scores indicate better knee conditions, while lower scores indicate worse knee conditions. |
| Knee Society Score (KSS) | Pre-operative (baseline) and 10-years post-operative | The KSS evaluates pain, stability and range of motion. The scale ranges between scores of 0-100. The maximum score of 100 points is reached when there is no pain, with good alignment of the knee in extension, and at least 125° of range of motion, without any anteroposterior or mediolateral instability. Deductions are made for flexion contracture, loss of extension and poor alignment. Higher scores indicate better knee conditions, while lower scores indicate worse knee conditions. |
| 12-Item Short Form Health Survey (SF-12): Physical Health Score | Pre-operative (baseline) and 10-years post-operative | The SF-12 questionnaire uses questions selected from the longer SF-36 Health Survey to measure patient wellness and quality of life. The scoring algorithm is calibrated so that an average healthy person would have a t-score of 50 points with a standard deviation of 10. Higher scores indicate better physical health. |
| Comparison of Radiographic Success/Failure Between Groups | 10 years post-operative | Radiographic review for success and or failure of the TKA prostheses at 10 years post-operation. A migrating or shifting prosthesis with or without the disappearance of radiolucent lines is considered a failure. |
| 12-Item Short Form Health Survey (SF-12): Mental Health Score | Pre-operative (baseline) and 10-years post-operative | The SF-12 questionnaire uses questions selected from the longer SF-36 Health Survey to measure patient wellness and quality of life. The scoring algorithm is calibrated so that an average healthy person would have a t-score of 50 points with a standard deviation of 10. Higher scores indicate better mental health. |
Countries
United States
Participant flow
Recruitment details
Patients were recruited at the following sites: Mayo Clinic in Rochester, MN, Mayo Clinic in Florida, and Mayo Clinic in Arizona. Patients, who met study criteria, planning to undergo a total knee replacement were offered study participation at their pre-operative visit.
Participants by arm
| Arm | Count |
|---|---|
| Control Stryker Orthopaedics N2Vac Polyethylene when used with a Triathlon Posterior Stabilized total knee system. This is a fixed- bearing knee intended for use in patients undergoing cemented total knee arthroplasty.
N2Vac Polyethylene: Ultra-high-molecular-weight polyethylene (UHMWPE). | 254 |
| Treatment X3 Polyethylene when used with a Triathlon Posterior Stabilized total knee system. This is a fixed- bearing knee intended for use in patients undergoing cemented total knee arthroplasty.
Stryker X3 Crosslink Polyethylene: Highly cross-linked polyethylene (HXLPE). | 264 |
| Total | 518 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 |
|---|---|---|---|
| Overall Study | Death | 55 | 50 |
| Overall Study | Lost to Follow Up or Lack of Efficacy | 36 | 51 |
Baseline characteristics
| Characteristic | Treatment | Total | Control |
|---|---|---|---|
| Age, Continuous | 67 years STANDARD_DEVIATION 9 | 67 years STANDARD_DEVIATION 9 | 67 years STANDARD_DEVIATION 9 |
| BMI, kg/m^2 | 32 Kilogram-Square Meter (kg/m^2) STANDARD_DEVIATION 6 | 32 Kilogram-Square Meter (kg/m^2) STANDARD_DEVIATION 7 | 32 Kilogram-Square Meter (kg/m^2) STANDARD_DEVIATION 7 |
| Height (cm) | 169 centimeters STANDARD_DEVIATION 10 | 169 centimeters STANDARD_DEVIATION 10 | 169 centimeters STANDARD_DEVIATION 10 |
| Previous knee surgery, n (%) No, previous knee surgery | 179 Participants | 336 Participants | 157 Participants |
| Previous knee surgery, n (%) Unknown | 3 Participants | 9 Participants | 6 Participants |
| Previous knee surgery, n (%) Yes, previous knee surgery | 82 Participants | 173 Participants | 91 Participants |
| Race and Ethnicity Not Collected | — | 0 Participants | — |
| Sex: Female, Male Female | 155 Participants | 300 Participants | 145 Participants |
| Sex: Female, Male Male | 109 Participants | 218 Participants | 109 Participants |
| Weight (kg) | 92 kilograms STANDARD_DEVIATION 21 | 92 kilograms STANDARD_DEVIATION 21 | 92 kilograms STANDARD_DEVIATION 21 |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 55 / 254 | 50 / 264 |
| other Total, other adverse events | 0 / 254 | 0 / 264 |
| serious Total, serious adverse events | 0 / 254 | 0 / 264 |
Outcome results
Primary
Prosthesis Survivorship Free of Revision
The survival of prostheses free of revision 10 years post operation.
Time frame: From operation to 10 years post-operative
Population: Patients were recruited from three academic, tertiary-care referral centers within one healthcare network. Patients approached for enrollment received a primary unilateral total knee arthroplasty (TKA) for a diagnosis of osteoarthritis (OA), avascular necrosis (AVN) or posttraumatic arthritis.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| Control | Prosthesis Survivorship Free of Revision | 96 percentage of prosthesis survivorship |
| Treatment | Prosthesis Survivorship Free of Revision | 97 percentage of prosthesis survivorship |
p-value: 0.4795% CI: [0.29, 1.77]Regression, Cox
Secondary
12-Item Short Form Health Survey (SF-12): Mental Health Score
The SF-12 questionnaire uses questions selected from the longer SF-36 Health Survey to measure patient wellness and quality of life. The scoring algorithm is calibrated so that an average healthy person would have a t-score of 50 points with a standard deviation of 10. Higher scores indicate better mental health.
Time frame: Pre-operative (baseline) and 10-years post-operative
Population: Patients who completed the SF-12 Mental Health Score at baseline and patients who completed the SF-12 Mental Health Score at 10-years post-operation.~Data was not collected nor analyzed for 187 patients in the control arm, and 193 patients in the treatment arm at the 10 year follow-up.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Control | 12-Item Short Form Health Survey (SF-12): Mental Health Score | Baseline Score | 56 score on a scale | Standard Deviation 9.64 |
| Control | 12-Item Short Form Health Survey (SF-12): Mental Health Score | 10-Year Follow-Up Score | 56.8 score on a scale | Standard Deviation 6 |
| Treatment | 12-Item Short Form Health Survey (SF-12): Mental Health Score | Baseline Score | 56.2 score on a scale | Standard Deviation 8.89 |
| Treatment | 12-Item Short Form Health Survey (SF-12): Mental Health Score | 10-Year Follow-Up Score | 56.3 score on a scale | Standard Deviation 7.65 |
Secondary
12-Item Short Form Health Survey (SF-12): Physical Health Score
The SF-12 questionnaire uses questions selected from the longer SF-36 Health Survey to measure patient wellness and quality of life. The scoring algorithm is calibrated so that an average healthy person would have a t-score of 50 points with a standard deviation of 10. Higher scores indicate better physical health.
Time frame: Pre-operative (baseline) and 10-years post-operative
Population: Patients who completed the SF-12 Physical Health Score at baseline and patients who completed the SF-12 Physical Health Score at 10-years post-operation.~Data was not collected nor analyzed for 187 patients in the control arm, and 193 patients in the treatment arm at the 10 year follow-up.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Control | 12-Item Short Form Health Survey (SF-12): Physical Health Score | Baseline Score | 32.5 score on a scale | Standard Deviation 8.34 |
| Control | 12-Item Short Form Health Survey (SF-12): Physical Health Score | 10-Year Follow-Up Score | 41.9 score on a scale | Standard Deviation 11.28 |
| Treatment | 12-Item Short Form Health Survey (SF-12): Physical Health Score | Baseline Score | 33.2 score on a scale | Standard Deviation 8.59 |
| Treatment | 12-Item Short Form Health Survey (SF-12): Physical Health Score | 10-Year Follow-Up Score | 44.4 score on a scale | Standard Deviation 10.37 |
Secondary
Comparison of Radiographic Success/Failure Between Groups
Radiographic review for success and or failure of the TKA prostheses at 10 years post-operation. A migrating or shifting prosthesis with or without the disappearance of radiolucent lines is considered a failure.
Time frame: 10 years post-operative
Population: Patients who completed 10-year post-operation radiographs of the study-related prosthetic joint.
| Arm | Measure | Group | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|---|
| Control | Comparison of Radiographic Success/Failure Between Groups | Loosening and/or Osteolysis | 0 Participants |
| Control | Comparison of Radiographic Success/Failure Between Groups | Tibial component bone-cement interface: Non-progressive radiolucent lines | 7 Participants |
| Control | Comparison of Radiographic Success/Failure Between Groups | Femoral component bone-prosthesis interface: Radiolucent lines | 3 Participants |
| Treatment | Comparison of Radiographic Success/Failure Between Groups | Loosening and/or Osteolysis | 0 Participants |
| Treatment | Comparison of Radiographic Success/Failure Between Groups | Tibial component bone-cement interface: Non-progressive radiolucent lines | 2 Participants |
| Treatment | Comparison of Radiographic Success/Failure Between Groups | Femoral component bone-prosthesis interface: Radiolucent lines | 0 Participants |
Secondary
Knee Society Score (KSS)
The KSS evaluates pain, stability and range of motion. The scale ranges between scores of 0-100. The maximum score of 100 points is reached when there is no pain, with good alignment of the knee in extension, and at least 125° of range of motion, without any anteroposterior or mediolateral instability. Deductions are made for flexion contracture, loss of extension and poor alignment. Higher scores indicate better knee conditions, while lower scores indicate worse knee conditions.
Time frame: Pre-operative (baseline) and 10-years post-operative
Population: Patients who completed the Knee Society Score at baseline and patients who completed the Knee Society Score at 10-years post-operation.~Data was not collected nor analyzed for 90 patients in the control arm, and 93 patients in the treatment arm at the 10 year follow-up.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Control | Knee Society Score (KSS) | Baseline Score | 39.9 score on a scale | Standard Deviation 14.19 |
| Control | Knee Society Score (KSS) | 10-Year Follow-Up Score | 77.6 score on a scale | Standard Deviation 8.6 |
| Treatment | Knee Society Score (KSS) | Baseline Score | 39.0 score on a scale | Standard Deviation 12.56 |
| Treatment | Knee Society Score (KSS) | 10-Year Follow-Up Score | 76.5 score on a scale | Standard Deviation 6.32 |
Secondary
Knee Society Score (KSS): Function
The Function KSS evaluates the walking distance and the act of climbing and descending stairs. The scale ranges between 0-100. The maximum score of 100 points is attributed to the individual capable of walking unlimited distances without walking aids, and of climbing and descending stairs normally. Deductions are made for the use of canes, crutches or walking frame. Higher scores indicate better knee conditions, while lower scores indicate worse knee conditions.
Time frame: Pre-operative (baseline) and 10-years post-operative
Population: Patients who completed the Knee Society Function Score at baseline and patients who completed the Knee Society Function Score at 10-years post-operation.~Data was not collected nor analyzed for 62 patients in the control arm, and 47 patients in the treatment arm at the 10 year follow-up.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Control | Knee Society Score (KSS): Function | Baseline Score | 58.3 score on a scale | Standard Deviation 17.38 |
| Control | Knee Society Score (KSS): Function | 10-Year Follow-Up Score | 70.2 score on a scale | Standard Deviation 26.25 |
| Treatment | Knee Society Score (KSS): Function | Baseline Score | 59.1 score on a scale | Standard Deviation 15.48 |
| Treatment | Knee Society Score (KSS): Function | 10-Year Follow-Up Score | 70.3 score on a scale | Standard Deviation 26.16 |
Secondary
Prosthesis Survivorship Free of Complications
The survival of prostheses free of related complications (non-operative) 10 years post operation.
Time frame: From operation to 10 years post-operative
Population: Patients were recruited from three academic, tertiary-care referral centers within one healthcare network. Patients approached for enrollment received a primary unilateral total knee arthroplasty (TKA) for a diagnosis of osteoarthritis (OA), avascular necrosis (AVN) or posttraumatic arthritis.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| Control | Prosthesis Survivorship Free of Complications | 84.9 percentage of prosthesis survivorship |
| Treatment | Prosthesis Survivorship Free of Complications | 88.8 percentage of prosthesis survivorship |
p-value: 0.19395% CI: [0.45, 1.18]Regression, Cox
Secondary
Prosthesis Survivorship Free of Reoperation
The survival of prostheses free of reoperation 10 years post operation.
Time frame: From operation to 10 years post-operative
Population: Patients were recruited from three academic, tertiary-care referral centers within one healthcare network. Patients approached for enrollment received a primary unilateral total knee arthroplasty (TKA) for a diagnosis of osteoarthritis (OA), avascular necrosis (AVN) or posttraumatic arthritis.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| Control | Prosthesis Survivorship Free of Reoperation | 92 percentage of prosthesis survivorship |
| Treatment | Prosthesis Survivorship Free of Reoperation | 96 percentage of prosthesis survivorship |
p-value: 0.0695% CI: [0.23, 1.03]Regression, Cox