163 – MINIMUM TEN YEAR RESULTS OF THE GENESIS II TOTAL KNEE ARTHROPLASTY SYSTEM

Abstract

Purpose: The Genesis II total knee arthroplasty system was introduced in 1996 as the next evolution in TKR design characterized by “built-in” femoral external rotation and improved trochlear design to optimize patellar tracking and femoral/tibial kinematics, as well as a polished tibial base plate and ethylene-oxide sterilized polyethylene to minimize wear. The purpose of this prospective study was to evaluate the long-term (minimum 10 year) clinical and radiographic results and survivorship of this novel TKA implant system.

Method: Between 1996 and 1999, 478 Genesis II Primary TKRs were implanted and followed prospectively in 414 patients (mean follow-up 11.25±1.11 years). Diagnosis at index surgery included: 94% osteoarthritis, 5% inflammatory arthritis, 1% other diagnoses. Average age at index TKR was 68 years (range 38 to 93 years). There were 149 posterior cruciate retaining (31%) and 329 cruciate sacrificing (69%) knees implanted. Patella resurfacing was performed on 89% (432) of the cases. Sixty-seven deaths occurred prior to 10 years follow-up. Patients were followed prospectively using validated clinical outcome scores (WOMAC, SF-12, Knee Society scores) and radiographs. Kaplan-Meier survival analysis was performed.

Results: All health-related outcomes were significantly improved from preoperative with a mean Knee Society Score and WOMAC at last follow-up of 162 and 69, respectively. To date, 16 revision procedures have been performed. Revisions for infection included six two-stage revisions and two cases of irrigation & debridement with polyethylene exchange. In addition, there were three re-operations for stiffness and one for patellar instability. To date, there have been only two revisions for aseptic loosening and/or osteolysis. Excluding revisions for infection, the Kaplan-Meier survivorship analysis of the total knee system was 98.9±0.5% at five years and 98.2±0.6% at 10 years.

Conclusion: The Genesis II total knee arthroplasty system, characterized by “built-in” femoral external rotation, improved trochlear design, a polished tibial base plate and ethylene-oxide sterilized polyethylene, has demonstrated excellent clinical & radiographic results and long-term survivorship (98% at 10 years) at our institution.