Avascular Necrosis, Knee Osteoarthritis, Post-traumatic; Arthrosis
Conditions
Keywords
primary total knee arthroplasty
Brief summary
The purpose of this prospective study is to evaluate Zimmer® iASSIST™ with respect to radiographic, clinical and economic outcomes and compared to conventional instrumentation in primary total knee arthroplasty (NexGen or Persona knee implants).
Detailed description
The study design is a prospective, multicenter, comparative outcome study. The study requires each site to obtain IRB (Institutional Review Board) approval prior to study enrollment. All potential study subjects will be required to participate in the Informed Consent Process. All study subjects will undergo preoperative clinical evaluations prior to their total knee arthroplasty. Investigators will collect clinical data for 12 months. Follow-up clinical visits include 3 and 12 months post-operatively. The primary endpoint of this study is defined as component alignment as determined using long leg X-Rays. The secondary endpoint will be to evaluate the Knee Society Score, EQ-5D (EuroQol-5Dimensions) scoring system, operating room time, blood loss and complications
Interventions
PROCEDUREtotal knee arthroplasty
surgical procedure in which damaged parts of the knee joint are replaced with an implant.
Sponsors
Zimmer, GmbH
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
SINGLE (Subject)
Masking description
Study patients will not know if their knee prosthesis will be implanted with iAssist or with conventional instrumentation
Intervention model description
2 groups of patients: 1 will have the knee prosthesis implanted with iAssist and the other with conventional instrumentation.
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Patient is male or female * Patient needs a primary total knee replacement using the NexGen LPS Flex or Persona knee implant * Patient is diagnosed with non-inflammatory degenerative joint disease (e.g., osteoarthritis, post-traumatic arthritis, avascular necrosis, etc.) * Patient is over 18 years old * Patient is able to: * Understand what participation in the study entails and willing to consent (patient or his/her legal guardian) to participate in the study by signing and dating an IRB/EC (ethics committee) approved inform consent form, and * Follow surgeon/staff instructions, and * Return for all follow-up evaluations, and * Able and willing to undergo a preoperative full-leg, standing radiographs and/or CT-scan * Patient meets an acceptable preoperative medical clearance and is free of or treated for cardiac, pulmonary, hematological or other conditions that would pose excessive operative risk. * Patient has a presence of varus or valgus deformity of 15 degrees or less.
Exclusion criteria
* Patient is currently enrolled in an investigational new drug or device study. * Patient has an active infection (including septic knee, distant infection, or osteomyelitis). * Patient has severe hip arthrosis. * Patient has neurological disorders (including, but not limited to Parkinson's disease). * Patient has had a prior ipsilateral unicompartmental knee arthroplasty, TKA, knee fusion or patellectomy. * Patient has hip or knee ankylosis. * Patient has inflammatory joint disease. * Patient has rheumatoid knee arthritis. * Patient has indications of intra- and/or extra-articular deformations that would eliminate or tend to eliminate adequate implant support or prevent the use of an appropriately sized implant, such as polio, history of tibial plateau fracture, etc. * Patient has any metal within 150 mm of the joint line for the operative-side knee. * Patient has knee deformities greater than 15 degrees of fixed varus, valgus, or flexion contracture on initial physical examination. * Female who is pregnant or lactating. * Patient currently involved in any personal injury litigation, medical-legal or worker's compensation claims. * Patient has arterial disease or stents that would exclude the use of a tourniquet. * Patient has insufficient quality or quantity of bone to support the implant due to prior knee surgery (or surgeries), cancer, metabolic bone disease, osteoporosis/osteopenia (diagnosed or treated with medication), active/old/remote infection, etc. * Patient has a mental condition that may interfere with his/her ability to give an informed consent or interfere with his/her ability or willingness to fulfill the requirements of the study. * Patient has a condition that would place excessive demands on the implant (e.g., Charcot's joints, muscle deficiencies, multiple joint disabilities, skeletal immaturity, etc.). * Patient has collateral ligament insufficiency. * Patient has an immunosuppressive disorder (e.g., AIDS, etc.) that would require cytotoxic drugs, corticosteroids, large dose of irradiation, or antilymphocytic serum. * Patient has an existing condition that would, in the opinion of the investigator, compromise participation or follow-up in this study.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Component Alignment | 1 year | Assess the differences in component alignment, measured by the mean of radiographs, between iASSIST™ and conventional instrumentation in primary total knee arthroplasty (TKA) procedures. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Knee Society Score Assessment | 1 year | Assess the differences in Knee Society Score between iASSIST™ and conventional instrumentation in primary TKA procedures. Higher (and better) score value: 100, lower value: 0. Score 80-100 = Excellent Score 70-79 = Good Score 60-69 = Fair Score below 60 = Poor |
| Knee Society Score Function | 1 year | Knee Society Score function asses 12 months postoperatively between iASSIST™ and conventional instrumentation in primary TKA procedures. Higher (and better) score value: 100, lower value: 0. Score 80-100 = Excellent Score 70-79 = Good Score 60-69 = Fair Score below 60 = Poor |
| EQ-5D Questionnaire | 1 year | Assess the differences in EQ-5D between iASSIST™ and conventional instrumentation in primary TKA procedures at 12 months postoperatively. Comparison of the derived EQ-5D scale and health state between the 2 groups. The EQ-5D questionnaire includes five dimensions (5D): mobility, self-care, usual activities, pain/discomfort, and anxiety/depression. EQ-5D values range from -0.2 to 1 where the negative values correspond to bad health states (states worse than death), and 1.0 corresponds to perfect health. |
Countries
Spain, Switzerland
Participant flow
Pre-assignment details
75 patients were intended to be enrolled according to the protocol but only 72 were finally enrolled.
Participants by arm
| Arm | Count |
|---|---|
| iAssist Group 45 iASSIST cases have been enrolled in 3 sites between April 2014 and August 2017. | 45 |
| Conventional Instrumentation Group 27 conventional cases have been enrolled in 3 sites between April 2014 and August 2017. | 27 |
| Total | 72 |
Baseline characteristics
| Characteristic | Conventional Instrumentation Group | Total | iAssist Group |
|---|---|---|---|
| Age, Continuous | 70.3 years STANDARD_DEVIATION 7.4 | 68.4 years STANDARD_DEVIATION 7.8 | 67.3 years STANDARD_DEVIATION 7.9 |
| Body Mass Index (BMI) kg/m^2 | 30.7 kg/m^2 STANDARD_DEVIATION 4.6 | 30.5 kg/m^2 STANDARD_DEVIATION 5.1 | 30.4 kg/m^2 STANDARD_DEVIATION 5.5 |
| Height cm | 166.0 cm STANDARD_DEVIATION 9.6 | 164.5 cm STANDARD_DEVIATION 10.3 | 163.5 cm STANDARD_DEVIATION 10.6 |
| Race and Ethnicity Not Collected | — | 0 Participants | — |
| Sex: Female, Male Female | 17 Participants | 47 Participants | 30 Participants |
| Sex: Female, Male Male | 10 Participants | 25 Participants | 15 Participants |
| Weight kg | 84.3 kg STANDARD_DEVIATION 13 | 82.5 kg STANDARD_DEVIATION 15.7 | 81.4 kg STANDARD_DEVIATION 17.2 |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 45 | 0 / 27 |
| other Total, other adverse events | 7 / 45 | 3 / 27 |
| serious Total, serious adverse events | 2 / 45 | 4 / 27 |
Outcome results
Primary
Component Alignment
Assess the differences in component alignment, measured by the mean of radiographs, between iASSIST™ and conventional instrumentation in primary total knee arthroplasty (TKA) procedures.
Time frame: 1 year
Population: Available data of enrolled patients were used for analysis.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| iAssist Group | Component Alignment | 179 degree | Standard Deviation 2.9 |
| Conventional Instrumentation Group | Component Alignment | 178 degree | Standard Deviation 3.9 |
Comparison: Hip Knee Angle value 1 year post surgery: Mean+/- SD (N)(Min, Max) 95%C.I (lower, upper)~iAssist group: 179.9 +/-2.9 (44) (171, 185.3)~Conventional group: 178.9 +/-3.9 (26) (167, 185)p-value: 0.2342t-test, 2 sided
Secondary
EQ-5D Questionnaire
Assess the differences in EQ-5D between iASSIST™ and conventional instrumentation in primary TKA procedures at 12 months postoperatively. Comparison of the derived EQ-5D scale and health state between the 2 groups. The EQ-5D questionnaire includes five dimensions (5D): mobility, self-care, usual activities, pain/discomfort, and anxiety/depression. EQ-5D values range from -0.2 to 1 where the negative values correspond to bad health states (states worse than death), and 1.0 corresponds to perfect health.
Time frame: 1 year
Population: Available data of enrolled patients were used for analysis.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| iAssist Group | EQ-5D Questionnaire | 0.8 score on a scale | Standard Deviation 0.2 |
| Conventional Instrumentation Group | EQ-5D Questionnaire | 0.8 score on a scale | Standard Deviation 0.3 |
Comparison: EQ-5D score 1 year post surgery: Mean+/- SD (N)(Min, Max) 95%C.I (lower, upper) iAssist group: 0.8 +/- 0.2 \[29\] (0.0, 1.0, 1.0), 95% C.I. (0.7, 0.9) Conventional group: 0.8 +/- 0.3 \[20\] (0.1, 0.8, 1.0), 95% C.I. (0.7, 0.9)p-value: 0.4549t-test, 2 sided
Secondary
Knee Society Score Assessment
Assess the differences in Knee Society Score between iASSIST™ and conventional instrumentation in primary TKA procedures. Higher (and better) score value: 100, lower value: 0. Score 80-100 = Excellent Score 70-79 = Good Score 60-69 = Fair Score below 60 = Poor
Time frame: 1 year
Population: Available data of enrolled patients were used for analysis.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| iAssist Group | Knee Society Score Assessment | 74.7 score on a scale | Standard Deviation 12.5 |
| Conventional Instrumentation Group | Knee Society Score Assessment | 72.4 score on a scale | Standard Deviation 11.6 |
Comparison: Knee Society Score Assessment 1 year post surgery: Mean+/- SD (N)(Min, Max) 95%C.I (lower, upper)~iAssist group: 74.7 +/- 12.5 \[44\] (30.2, 78.0, 89.5), 95% C.I. (70.9, 78.5)~Conventional group: 72.4 +/- 11.6 \[26\] (45.0, 75.2, 90.1), 95% C.I. (67.7, 77.1)p-value: 0.4427t-test, 2 sided
Secondary
Knee Society Score Function
Knee Society Score function asses 12 months postoperatively between iASSIST™ and conventional instrumentation in primary TKA procedures. Higher (and better) score value: 100, lower value: 0. Score 80-100 = Excellent Score 70-79 = Good Score 60-69 = Fair Score below 60 = Poor
Time frame: 1 year
Population: Available data of enrolled patients were used for analysis.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| iAssist Group | Knee Society Score Function | 80.5 score on a scale | Standard Deviation 13.8 |
| Conventional Instrumentation Group | Knee Society Score Function | 78.5 score on a scale | Standard Deviation 19.1 |
Comparison: Knee Soceity Score Function 1 year post surgery: Mean+/- SD (N)(Min, Max) 95%C.I (lower, upper) iAssist group: 80.5 +/- 13.8 \[44\] (55.0, 80.0, 100.0), 95% C.I. (76.2, 84.7) Conventional group: 78.5 +/- 19.1 \[26\] (40.0, 80.0, 100.0),95% C.I. (70.8, 86.2)p-value: 0.6154t-test, 2 sided