SUMMARY A prospective, randomized, single-blinded clinical trial is proposed to compare three tibial tray designs for patients undergoing total knee arthroplasty. This study is designed to address the clinically important issues of tibial component modularity and fixation in total knee replacement. The Zimmer NexGen Legacy knee system is an FDA approved device and in this study will be used with 1) a modular tibial tray inserted with cement and 2) a non-modular tibial tray inserted with cement, and 3) a non-modular tibial tray inserted without cement. The insertion of total knee components without cement has been done clinically for over 20 years but has not been specifically approved by the FDA. Thus treatment arm 3, a non-modular tray inserted without cement, would involve the so-called off-label use of the device.
136 cases will be assigned to each arm of the study. Each patient will be assessed two months after surgery, one year after surgery, two years after surgery, five years after surgery, and every three to five years thereafter. The principal outcome measures will be the Knee Society Clinical rating scale, the SF-36 and the presence of significant lucent lines.. These measures will be compared among patients in the 3 trial arms at 5 years post surgery (or at the last follow-up point for those who drop out or become lost to follow-up). The Knee Society scores and SF-36 scores will be analyzed using analysis of variance models Rates of significant lucencies, perioperative mortality, as well as complications such as deep vein thrombosis, pulmonary embolus, neurovascular complication, and infection will be compared among the groups using chi-square tests . Rates of revision surgery will be compared among the groups using survivorship methods.
PURPOSE The primary aim of the study is to compare the results obtained with each of three tibial designs for patients undergoing total knee arthroplasty. Those results will be measured with disease-specific (Knee Society Scores), global (SF-36), and outcome measures. Radiographic results consisting of standing alignment, lateral and skyline views of the surgical knee will be recorded and analyzed. Completion of the intial investigation will occur at the 5-year interval after the last enrolled patient.
Inclusion Criteria:
- Patients greater then or equal to 20 and less then or equal to 85 undergoing unilateral primary knee surgery for degenerative joint disease (DJD).
Exclusion Criteria:
- Age less than 20 years or > 85.
- Severe deformity great then or equal to 20 degrees varus, valgus malalignment or flexion deformity.
- Osteomyelitis, septicemia, prior infection of knee joint, or other active infections that may spread to other areas of the body.
- The presence of infections, highly communicable diseases, e.g. AIDS, active tuberculosis, venereal disease, and hepatitis.
- Significant neurological or musculoskeletal disorders or disease that may adversely affect normal gait or weight bearing.
- Metastatic disease.
- Any congenital, developmental, or other bone disease or previous knee surgery that may, in the surgeon's judgement, interfere with TK prosthesis survival or success, e.g. Paget's disease, Charcot's disease secondary to diabetes, severe osteoporosis, previous high tibial osteotomy, etc.
- Presence of previous prosthetic knee replacement device (any type).
- Arthrodesis of the affected knee.
- Patients not requiring patella resurfacing.
You will have a total knee replacement and receive one of three variations of a FDAapproved knee replacement system. The same femoral (thigh-bone) and patellar (kneecap) design will be used for all patients. Only the tibial (leg-bone) part of the knee replacement will differ among the 3 groups.
One of the tibial (leg-bone) components has separate metal and plastic parts that are assembled during surgery and cemented to the bone. One of the tibial (leg-bone) components has metal and plastic parts that are fused together by the manufacturer and then are cemented to the bone. One of the tibial (leg-bone) components has metal and plastic parts that are fused together by the manufacturer and are firmly inserted into the bone without cement. For over 20 years many surgeons have inserted the components of total knee replacements without cement but that technique has not been granted specific approval by the FDA.
You will come to the hospital on the day of surgery and remain for four to six days. Just prior to the surgery, you will be put in one of the three groups by chance (as in the flip of a coin). You will have approximately a 33% chance of receiving one design. Both the patient and research assistant who evaluates the patient after surgery will not know which implant was utilized. Each group will be treated the same after surgery with mobilization the day after surgery, therapy, and weight bearing as tolerated. Appropriate x-rays, physical examination of the knee, and a simple survey will be obtained prior to surgery and five years after surgery. Patients with severe leg deformity, active infection or severe nerve disease, or previous knee replacement surgery will be excluded from the study.
Will I need to pay for tests and procedures?
You and/or your health plan will need to pay for all tests and procedures that are part of this study because they are needed for your regular medical care.
Participants may be in this research study for up to five years.
Last updated: 05/25/2012
NCT ID: NCT00589147
IRB Number:2320-02
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