Knee Osteoarthritis
Conditions
Keywords
total knee arthroplasty, vitamin E, polyethylene, aseptic loosening, osteolysis
Brief summary
The aim of this observational study is to investigate if there is any difference in survival rate, clinical and radiological results after total knee replacement with vitamin E-blended polyethylene in comparison to conventional polyethylene at minimum 7-year follow-up
Interventions
DEVICEGKS Prime Flex Mobile knee
Total knee arthroplasty with a cemented mobile bearing bicompartmental knee prosthesis
Sponsors
Permedica spa
Study design
Observational model
COHORT
Time perspective
CROSS_SECTIONAL
Eligibility
Sex/Gender
ALL
Age
18 Years to 85 Years
Healthy volunteers
No
Inclusion criteria
* Patient who received primary cemented total knee arthroplasty with GKS Prime Flex Mobile knee by Permedica Orthopaedics with vitamin E polyethylene bearing or with conventional polyethylene bearing. * Minimum 7-year follow-up; * Age ≥ 18 and \< 85 years; * Patient who signed informed consent.
Exclusion criteria
* Patient who received primary cemented total knee arthroplasty with a different knee prosthetic design; * Patient already enrolled in other clinical studies.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Implant Survival for Aseptic Loosening | 10-year follow-up | Kaplan-Meier cumulative survival with revision due to aseptic loosening as the end-point |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Implant Survival for Any Reason | 10-year follow-up | Kaplan-Meier cumulative survival with revision due to any reason as the end-point |
| Forgotten Joint Score (FJS-12) | At mean follow-up of 8.5 years and 8.3 years for Vitamin E and Polyethylene, respectively | Patient related outcome measurement scored from 0 to 100 (higher scores mean better outcomes) |
| American Knee Society Score (KSS) | At mean follow-up of 8.5 years and 8.3 years for Vitamin E and Polyethylene, respectively | Clinical and Functional scores of the knee. Both scores are scored from 0 to 100 (higher scores mean better outcomes) |
| Periprosthetic Radiolucent Line | At mean follow-up of 8.5 years and 8.3 years for Vitamin E and Polyethylene, respectively | Radiographic sign of bone remodelling around the implant |
| Periprosthetic Osteolysis | At mean follow-up of 8.5 years and 8.3 years for Vitamin E and Polyethylene, respectively | Radiographic sign of focal bone resorption around the implant |
Countries
Italy
Participant flow
Recruitment details
During recruitment process, 350 total knee arthroplasties (181 with vitamin E polyethylene and 169 with conventional polyethylene) were identified as eligible. Overall 151 total knee arthroplasties were lost to follow-up and were not enrolled (79 with vitamin E polyethylene and 72 with conventional polyethylene). 186 participants (199 knees) were enrolled.
Pre-assignment details
186 participants (199 knees) were enrolled in the study and were assigned to each arm
Participants by arm
| Arm | Count |
|---|---|
| VITAMIN E Patients who received cemented total knee arthroplasty with vitamin E blended polyethylene mobile bearing
GKS Prime Flex Mobile knee: Total knee arthroplasty with a cemented mobile bearing bicompartmental knee prosthesis | 95 |
| VITAMIN E Patients who received cemented total knee arthroplasty with vitamin E blended polyethylene mobile bearing
GKS Prime Flex Mobile knee: Total knee arthroplasty with a cemented mobile bearing bicompartmental knee prosthesis | 102 |
| POLYETHYLENE Patients who received cemented total knee arthroplasty with conventional polyethylene mobile bearing
GKS Prime Flex Mobile knee: Total knee arthroplasty with a cemented mobile bearing bicompartmental knee prosthesis | 91 |
| POLYETHYLENE Patients who received cemented total knee arthroplasty with conventional polyethylene mobile bearing
GKS Prime Flex Mobile knee: Total knee arthroplasty with a cemented mobile bearing bicompartmental knee prosthesis | 97 |
| Total | 385 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 |
|---|---|---|---|
| Overall Study | Adverse Event | 18 | 16 |
| Overall Study | Death | 4 | 21 |
Baseline characteristics
| Characteristic | VITAMIN E | POLYETHYLENE | Total |
|---|---|---|---|
| Age, Continuous | 65.3 years STANDARD_DEVIATION 6.7 | 75.3 years STANDARD_DEVIATION 5.7 | 70.1 years STANDARD_DEVIATION 7.9 |
| BMI | 29.9 kg/m^2 STANDARD_DEVIATION 5.9 | 27.8 kg/m^2 STANDARD_DEVIATION 5.1 | 29.0 kg/m^2 STANDARD_DEVIATION 5.6 |
| Diagnosis Osteoarthritis | 98 Knees (Knee implants) | 96 Knees (Knee implants) | 194 Knees (Knee implants) |
| Diagnosis Post-traumatic osteoarthritis | 2 Knees (Knee implants) | 1 Knees (Knee implants) | 3 Knees (Knee implants) |
| Diagnosis Rheumatoid arthritis | 2 Knees (Knee implants) | 0 Knees (Knee implants) | 2 Knees (Knee implants) |
| Follow-up | 8.5 years STANDARD_DEVIATION 2.1 | 8.3 years STANDARD_DEVIATION 2.2 | 8.4 years STANDARD_DEVIATION 2.1 |
| Race and Ethnicity Not Collected | — | — | 0 Participants |
| Sex: Female, Male Female | 61 Knees (Knee implants) | 80 Knees (Knee implants) | 141 Knees (Knee implants) |
| Sex: Female, Male Male | 41 Knees (Knee implants) | 17 Knees (Knee implants) | 58 Knees (Knee implants) |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 4 / 102 | 21 / 97 |
| other Total, other adverse events | 22 / 102 | 14 / 97 |
| serious Total, serious adverse events | 18 / 102 | 16 / 97 |
Outcome results
Primary
Implant Survival for Aseptic Loosening
Kaplan-Meier cumulative survival with revision due to aseptic loosening as the end-point
Time frame: 10-year follow-up
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| VITAMIN E | Implant Survival for Aseptic Loosening | 95.0 percentage of survival implants |
| POLYETHYLENE | Implant Survival for Aseptic Loosening | 97.8 percentage of survival implants |
Secondary
American Knee Society Score (KSS)
Clinical and Functional scores of the knee. Both scores are scored from 0 to 100 (higher scores mean better outcomes)
Time frame: At mean follow-up of 8.5 years and 8.3 years for Vitamin E and Polyethylene, respectively
Population: Knees of patients who returned back to the hospital for complete clinical and radiographic follow-up
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| VITAMIN E | American Knee Society Score (KSS) | KSS - Knee score | 84 score on a scale | Standard Deviation 16 |
| VITAMIN E | American Knee Society Score (KSS) | KSS - Function score | 77 score on a scale | Standard Deviation 26 |
| POLYETHYLENE | American Knee Society Score (KSS) | KSS - Knee score | 80 score on a scale | Standard Deviation 16 |
| POLYETHYLENE | American Knee Society Score (KSS) | KSS - Function score | 63 score on a scale | Standard Deviation 31 |
Secondary
Forgotten Joint Score (FJS-12)
Patient related outcome measurement scored from 0 to 100 (higher scores mean better outcomes)
Time frame: At mean follow-up of 8.5 years and 8.3 years for Vitamin E and Polyethylene, respectively
Population: Number of knees of patients who was contacted by phone or who returned back to hospital for clinical examination follow-up
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| VITAMIN E | Forgotten Joint Score (FJS-12) | 59 score on a scale | Standard Deviation 30 |
| POLYETHYLENE | Forgotten Joint Score (FJS-12) | 56 score on a scale | Standard Deviation 27 |
Secondary
Implant Survival for Any Reason
Kaplan-Meier cumulative survival with revision due to any reason as the end-point
Time frame: 10-year follow-up
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| VITAMIN E | Implant Survival for Any Reason | 87.6 percentage of survival implants |
| POLYETHYLENE | Implant Survival for Any Reason | 89.6 percentage of survival implants |
Secondary
Periprosthetic Osteolysis
Radiographic sign of focal bone resorption around the implant
Time frame: At mean follow-up of 8.5 years and 8.3 years for Vitamin E and Polyethylene, respectively
Population: Knees of patients who returned back to hospital for clinical and radiographic follow-up
| Arm | Measure | Value (COUNT_OF_UNITS) |
|---|---|---|
| VITAMIN E | Periprosthetic Osteolysis | 1 Knees (knee implants) |
| POLYETHYLENE | Periprosthetic Osteolysis | 1 Knees (knee implants) |
Secondary
Periprosthetic Radiolucent Line
Radiographic sign of bone remodelling around the implant
Time frame: At mean follow-up of 8.5 years and 8.3 years for Vitamin E and Polyethylene, respectively
Population: Knees of patients who returned back to hospital for clinical and radiographic follow-up.
| Arm | Measure | Value (COUNT_OF_UNITS) |
|---|---|---|
| VITAMIN E | Periprosthetic Radiolucent Line | 28 Knees (knee implants) |
| POLYETHYLENE | Periprosthetic Radiolucent Line | 10 Knees (knee implants) |