Avascular Necrosis, Inflammatory Tissue Disorder, Osteoarthritis, Post-traumatic Arthritis, Secondary Arthritis
Conditions
Brief summary
To evaluate the safety and efficacy of the Encore Mobile-Bearing Knee.
Interventions
DEVICEEncore Mobile-Bearing Knee
Used for primary total knee replacement
Sponsors
Encore Medical, L.P.
Study design
Allocation
NON_RANDOMIZED
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Skeletal maturity * Less than 70 on preoperative Knee Society Score (Rating Score) * Sufficient bone stock, as judged by radiographs, to support primary knee implant * Patients with inflammatory tissue disorders, osteoarthritis, post-traumatic arthritis, secondary arthritis, or avascular necrosis of the femoral condyles * Patient is not pregnant * Primary total knee replacement * Sufficient collateral ligaments to support device, as judged by physician during stability testing (varus/valgus and flexion/extension) * Varus deformity \<45 or valgus deformity \<45 or fixed flexion deformity \<90 * Patient is likely to be available for evaluation for the duration of the study * Able and willing to sign the informed consent and follow study procedures
Exclusion criteria
* Skeletal immaturity * Greater than or equal to 70 on preoperative Knee Society Score (Rating Scale) * Previous knee surgery that has adversely affected bone stock or prior total knee replacement * Post patellectomy * Patient is pregnant * Insufficient collateral ligaments, as judged by the physician * Neurological conditions that might hinder patient's ability to follow study procedures (i.e., any that restrict physical activities such as Parkinson's Disease, Multiple Sclerosis, previous stroke which affects lower extremity). * Varus deformity \>45 or valgus deformity \>45 or fixed flexion deformity \>90. * Mental conditions that may interfere with ability to give an informed consent or willingness to fulfill the study requirements (i.e., severe mental retardation such that the patient cannot understand the informed consent process, global dementia, prior strokes that interfere the with patient's cognitive abilities, senile dementia, and Alzheimer's Disease). * Prisoners * Conditions that place excessive demand on the implant (i.e. Charcot's joints, muscle deficiencies, refusal to modify postoperative physical activities, skeletal immaturity).
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Knee Society Score Evaluation | 2 year | The Knee Society Score includes a knee rating and function score. This evaluation covers the knee rating score with three main parameters of pain, stability and range of motion and that flexion contracture, extension lag and misalignment should be dealt with as deductions. Thus, 100 points will be obtained by a well-aligned knee with no pain, 125 degrees of motion, and negligible anteroposterior and mediolateral instability. 50 points are allotted for pain, 25 for stability, and 25 for range of motion. Grading for KS Score: Excellent (90-100), Good (80-90), Fair (70-79) and Poor (\<70). |
| Knee Society Function Score | 2 year | The patient function score considers only walking distance and stair climbing, with deductions for walking aids. The maximum function score is obtained by a patient who can walk an unlimited distance and go up and down stairs normally. Walking ability is expressed in blocks (approximately 100 meters). Stair climbing is considered normal if the patient can ascend and descend stairs without holding a railing. A score of \> or = to 60 on the function score is considered success. Minimum score = 0, maximum score = 100 with the higher the score representing a better outcome. |
| Knee Society Scores Used as Success/Failure Criteria. | 2 year | The maximum score for each of the sections is 100 points. A score of at least 80 points on the 2-year knee assessment score was defined as a success. |
Countries
United States
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| Mobile Bearing Knee Subjects who meet the inclusion/exclusion criteria and are treated and receive the Mobile Bearing Knee. The Encore Mobile Bearing Knee is intended for subjects presenting for a primary cemented knee replacement suffering from inflammatory tissue disorders, osteoarthritis, post-traumatic arthritis, secondary arthritis, or avascular necrosis of the femoral condyles. This design is indicated for subjects who have adequate, as judged by the physician, collateral ligamentous stability to support the implant. | 419 |
| Total | 419 |
Withdrawals & dropouts
| Period | Reason | FG000 |
|---|---|---|
| Overall Study | Adverse Event | 2 |
| Overall Study | Death | 9 |
| Overall Study | Lost to Follow-up | 95 |
| Overall Study | Protocol Violation | 18 |
| Overall Study | Withdrawal by Subject | 13 |
Baseline characteristics
| Characteristic | Mobile Bearing Knee |
|---|---|
| Age, Categorical <=18 years | 0 Participants |
| Age, Categorical >=65 years | 238 Participants |
| Age, Categorical Between 18 and 65 years | 181 Participants |
| Age Continuous | 66.8 years STANDARD_DEVIATION 10.2 |
| Region of Enrollment United States | 419 participants |
| Sex: Female, Male Female | 229 Participants |
| Sex: Female, Male Male | 190 Participants |
Adverse events
| Event type | EG000 affected / at risk |
|---|---|
| deaths Total, all-cause mortality | — / — |
| other Total, other adverse events | 281 / 419 |
| serious Total, serious adverse events | 0 / 419 |
Outcome results
Primary
Knee Society Function Score
The patient function score considers only walking distance and stair climbing, with deductions for walking aids. The maximum function score is obtained by a patient who can walk an unlimited distance and go up and down stairs normally. Walking ability is expressed in blocks (approximately 100 meters). Stair climbing is considered normal if the patient can ascend and descend stairs without holding a railing. A score of \> or = to 60 on the function score is considered success. Minimum score = 0, maximum score = 100 with the higher the score representing a better outcome.
Time frame: 2 year
Population: Out of the 282 subjects who completed the study, only 173 were analyzed due to either the 2 year visit being completed out of window or missing data.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Mobile Bearing Knee | Knee Society Function Score | 89.0 Average Knee Function Score | Standard Deviation 15.6 |
Primary
Knee Society Score Evaluation
The Knee Society Score includes a knee rating and function score. This evaluation covers the knee rating score with three main parameters of pain, stability and range of motion and that flexion contracture, extension lag and misalignment should be dealt with as deductions. Thus, 100 points will be obtained by a well-aligned knee with no pain, 125 degrees of motion, and negligible anteroposterior and mediolateral instability. 50 points are allotted for pain, 25 for stability, and 25 for range of motion. Grading for KS Score: Excellent (90-100), Good (80-90), Fair (70-79) and Poor (\<70).
Time frame: 2 year
Population: Out of the 282 subjects who completed the study, only 173 were analyzed due to either the 2 year visit being completed out of window or missing data.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Mobile Bearing Knee | Knee Society Score Evaluation | 93.1 Average Knee Rating Score | Standard Deviation 9.9 |
Primary
Knee Society Scores Used as Success/Failure Criteria.
The maximum score for each of the sections is 100 points. A score of at least 80 points on the 2-year knee assessment score was defined as a success.
Time frame: 2 year
Population: Out of the 282 subjects who completed the study, only 173 were analyzed due to either the 2 year visit being completed out of window or missing data.
| Arm | Measure | Group | Value (NUMBER) |
|---|---|---|---|
| Mobile Bearing Knee | Knee Society Scores Used as Success/Failure Criteria. | Knee Society Score Success | 91 Percentage of Participants with Success |
| Mobile Bearing Knee | Knee Society Scores Used as Success/Failure Criteria. | Knee Function Score Success | 84 Percentage of Participants with Success |