Osteoarthritis, Total Knee Arthroplasty
Conditions
Keywords
Total Knee Arthroplasty, Osteoarthritis, Knee
Brief summary
The purpose of this study is to test for significant differences in functional outcomes obtained by using a NexGen LPS versus a NexGen LPS-Flex knee implant. Specifically, it is predicted that an increase in postoperative range of motion will be experienced by patients treated with the NexGen LPS-Flex knee implant.
Detailed description
This study will compare the clinical results of the NexGen LPS femoral component with the higher flexion potential of the NexGen LPS-Flex femoral component in all patients with degenerative joint disease that require total knee arthroplasty. The primary variable of interest is postoperative range of motion achieved with the two devices, which are implanted with slightly different surgical techniques in patients who may also be subjected to different rehabilitation programs depending on the device they are assigned.
Interventions
DEVICENexGen LPS-Flex Fixed Bearing Knee
NexGen LPS-Flex Fixed Bearing femoral component
DEVICENexGen Legacy Posterior Stabilized Knee
NexGen Legacy Posterior Stabilized femoral component
Sponsors
Zimmer Biomet
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
SINGLE (Subject)
Eligibility
Sex/Gender
ALL
Age
21 Years to 80 Years
Healthy volunteers
No
Inclusion criteria
* Age, 21-80 years * Sex, Males and females will be included * BMI less than or equal to 39 and calf-thigh less than or equal to 90 degrees * Stable health, the patient would be able to undergo surgery and participate in the follow-up program based on physical examination and medical history. * Patient is willing and able to cooperate in follow-up therapy. * Patient exhibits preoperative radiographic evidence of joint degeneration consistent with TKA that cannot be treated in non-operative fashion. * Patient has stable and functional collateral ligaments. * Patient has potential to perform higher than average range of motion activities. * Operative side range of motion flexion greater than or equal to 90 degrees. * Severe knee pain and disability due to degenerative joint disease. * Patient or patient's legal representative has signed the Informed Consent form.
Exclusion criteria
* Previous history of infection in the affected joint. * Previously failed knee endoprosthesis of any kind. * Charcot joint disease or other severe neurosensory deficits. * Previous patellectomy. * Patient is skeletally immature. * Grossly insufficient femoral or tibial bone stock. * Patient is pregnant. * Varus or valgus deformity greater than 20 degrees. * Fixed flexion deformity greater than 15 degrees. * Previous high tibial osteotomy. * Previous femoral osteotomy. * Patient is a poor compliance risk - currently treated for ethanol or drug abuse, physical or mental handicap, etc. * Loss of musculature or absence of musculoligamentous supporting structures required for adequate soft tissue balance.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Postoperative Range of Motion (ROM) | 6 Weeks to 2 Years Post-op, based on on the intervals listed | Postoperative ROM was calculated by taking the measurement of patient flexion minus the measurement of patients' extension. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Return to Function (RtF) Via Knee Society Score (Modified) | 6 Weeks to 2 Years Post-op, based on on the intervals listed | Scores were calculated from responses on a modified Knee Society Score by the enrolled subjects for the stated visit intervals. Grading for the Knee Society Score is based on a scale from 0-100 and results are established follows: 80-100 =Excellent; 70-79 = Good; 60-69 = Fair; and Below 60 = Poor. |
Countries
Canada, United States
Participant flow
Recruitment details
Patients were enrolled between June 2001 and December 2007 at a total of 12 sites throughout the US/Canada
Participants by arm
| Arm | Count |
|---|---|
| LPS Flex Fixed Bearing Knee Study arm will consist of patients that are treated with the NexGen LPS-Flex Fixed Bearing Knee. | 164 |
| LPS Standard Knee Study arm will consist of patients that are treated with the NexGen Legacy Posterior Stabilized Knee. | 167 |
| Total | 331 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 |
|---|---|---|---|
| Overall Study | Adverse Event | 43 | 33 |
| Overall Study | CRF missing | 0 | 1 |
| Overall Study | Death | 1 | 2 |
| Overall Study | Lost to Follow-up | 3 | 3 |
| Overall Study | Study Prosthesis Removed | 1 | 0 |
| Overall Study | Withdrawal by Subject | 0 | 1 |
Baseline characteristics
| Characteristic | LPS Flex Fixed Bearing Knee | LPS Standard Knee | Total |
|---|---|---|---|
| Age Categorical <=18 years | 0 participants | 0 participants | 0 participants |
| Age Categorical >=65 years | 81 participants | 84 participants | 165 participants |
| Age Categorical Between 18 and 65 years | 83 participants | 82 participants | 165 participants |
| Age Continuous | 64.6 years STANDARD_DEVIATION 8.1 | 64.9 years STANDARD_DEVIATION 8.4 | 64.7 years STANDARD_DEVIATION 8.3 |
| Gender Female | 92 participants | 84 participants | 176 participants |
| Gender Male | 72 participants | 82 participants | 154 participants |
| Region of Enrollment Canada | 31 participants | 29 participants | 60 participants |
| Region of Enrollment United States | 133 participants | 138 participants | 271 participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | — / — | — / — |
| other Total, other adverse events | 27 / 164 | 23 / 167 |
| serious Total, serious adverse events | 13 / 164 | 19 / 167 |
Outcome results
Primary
Postoperative Range of Motion (ROM)
Postoperative ROM was calculated by taking the measurement of patient flexion minus the measurement of patients' extension.
Time frame: 6 Weeks to 2 Years Post-op, based on on the intervals listed
Population: Analysis was determined by calculating the measurements of the enrolled cases who completed the stated visit interval.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| LPS Flex Fixed Bearing Knee | Postoperative Range of Motion (ROM) | PostOp ROM @ 6 Weeks | 102.3 degrees | Standard Deviation 17.1 |
| LPS Flex Fixed Bearing Knee | Postoperative Range of Motion (ROM) | PostOp ROM @ 6 Months | 117.6 degrees | Standard Deviation 11.3 |
| LPS Flex Fixed Bearing Knee | Postoperative Range of Motion (ROM) | PostOp ROM @1 Year | 120.3 degrees | Standard Deviation 10.7 |
| LPS Flex Fixed Bearing Knee | Postoperative Range of Motion (ROM) | PostOp ROM @2 Year | 120.7 degrees | Standard Deviation 10.7 |
| LPS Standard Knee | Postoperative Range of Motion (ROM) | PostOp ROM @2 Year | 121.2 degrees | Standard Deviation 10.4 |
| LPS Standard Knee | Postoperative Range of Motion (ROM) | PostOp ROM @ 6 Weeks | 106.8 degrees | Standard Deviation 13.9 |
| LPS Standard Knee | Postoperative Range of Motion (ROM) | PostOp ROM @1 Year | 121.7 degrees | Standard Deviation 10.4 |
| LPS Standard Knee | Postoperative Range of Motion (ROM) | PostOp ROM @ 6 Months | 118.2 degrees | Standard Deviation 12.1 |
Secondary
Return to Function (RtF) Via Knee Society Score (Modified)
Scores were calculated from responses on a modified Knee Society Score by the enrolled subjects for the stated visit intervals. Grading for the Knee Society Score is based on a scale from 0-100 and results are established follows: 80-100 =Excellent; 70-79 = Good; 60-69 = Fair; and Below 60 = Poor.
Time frame: 6 Weeks to 2 Years Post-op, based on on the intervals listed
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| LPS Flex Fixed Bearing Knee | Return to Function (RtF) Via Knee Society Score (Modified) | PostOp KSSF @ 6 Week | 56.4 units on a scale | Standard Deviation 21.7 |
| LPS Flex Fixed Bearing Knee | Return to Function (RtF) Via Knee Society Score (Modified) | PostOp KSSF @ 6 Month | 79.2 units on a scale | Standard Deviation 19.5 |
| LPS Flex Fixed Bearing Knee | Return to Function (RtF) Via Knee Society Score (Modified) | PostOp KSSF @ 1 Year | 81.1 units on a scale | Standard Deviation 21.9 |
| LPS Flex Fixed Bearing Knee | Return to Function (RtF) Via Knee Society Score (Modified) | PostOp KSSF @ 2 Year | 84.3 units on a scale | Standard Deviation 18.9 |
| LPS Standard Knee | Return to Function (RtF) Via Knee Society Score (Modified) | PostOp KSSF @ 2 Year | 83.1 units on a scale | Standard Deviation 18.9 |
| LPS Standard Knee | Return to Function (RtF) Via Knee Society Score (Modified) | PostOp KSSF @ 6 Week | 58.5 units on a scale | Standard Deviation 19.8 |
| LPS Standard Knee | Return to Function (RtF) Via Knee Society Score (Modified) | PostOp KSSF @ 1 Year | 81.7 units on a scale | Standard Deviation 19.5 |
| LPS Standard Knee | Return to Function (RtF) Via Knee Society Score (Modified) | PostOp KSSF @ 6 Month | 79.7 units on a scale | Standard Deviation 20 |