Intermediate outcome of a cruciate-retaining tibia.

The use of an all-polyethylene tibia in total knee arthroplasty is being revisited as a means to decrease backside polyethylene wear and lessen cost. The Depuy Sigma all-polyethylene tibia (Depuy Orthopedics, Warsaw, Indiana) has been reported with good outcomes at a greater than 10-year interval, whereas the Biomet AGC I beam design (Biomet, Warsaw, Indiana) has had a high failure rate at an early interval. This is a retrospective review of another design. One hundred seventy patients (190 cruciate-retaining total knee replacements) with a Scorpio (Stryker, Mahwah, New Jersey) all-polyethylene implant and tibia were identified in the authors' registry. This implant was chosen for all octogenarians deemed fit for a cruciate-retaining knee and a few septuagenarians who were deemed likely to remain inactive postoperatively for reasons other than knee arthritis. Mean follow-up was 38 months (range, 24-83 months). Mean patient age was 83.1 years (range, 72.7-93.8 years). Twenty-seven patients (29 knees) were lost to follow-up. Nineteen patients (24 knees) died before 24-month follow-up; all implants were in place, and no deaths were associated with the index procedure. Fifty-one patients (55 knees) were followed by telephone interview only and 75 patients (81 knees) by an office visit with radiograph analysis. One tibia revision was performed 2 months postoperatively for an implant placed in extension and varus. No infections, component wear, radiolucent lines, or impending revisions of the remaining cohort occurred. Lower Extremity Activity Scale scores ranged from 2 to 10 (mean score, 6.8), which demonstrated success even in patients with an active lifestyle. This previously unreported design is a promising all-polyethylene tibia alternative for total knee arthroplasty in older patients.