THREE-YEAR FOLLOW-UP OF ALL-POLYETHYLENE VERSUS METAL-BACKED TIBIAL COMPONENTS IN PRIMARY TOTAL KNEE ARTHROPLASTY: A LONGITUDINAL CONTINUATION OF A PREVIOUS SIX MONTH COHORT STUDY

Abstract

Background: We previously reported six-month clinical and functional outcomes of all-polyethylene versus metal-backed tibial components in 48 patients undergoing primary total knee arthroplasty [1]. The present study extends this follow-up to three years in the same cohort. The objective is to evaluate the three-year clinical, functional, and radiological outcomes of AP versus MBT tibial components in the same 48 patients previously assessed at six months [1]. Materials and Methods: Of the 48 patients originally enrolled at the Department of Orthopedic Surgery, Sharif Medical City Hospital, Lahore, all 24 patients in each group were reassessed at a mean of 36 months postoperatively. Outcomes included the American Knee Society Score, Visual Analog Scale for pain, range of motion, complications, radiological findings (radiolucent lines, tibial subsidence, loosening), and patient satisfaction. Statistical analysis was performed using SPSS version 26.0. Results: At three years, AKSS, VAS, ROM, and functional scores remained comparable between the AP and MBT groups (all p > 0.05). No case of revision, aseptic loosening, or deep infection was observed in either group. Complication rates were identical (8.4% in each group), and 91.7% of patients in both groups reported being satisfied or very satisfied (p = 0.782). Improvements observed at six months were maintained without deterioration through the three-year time point [1]. Conclusion: Clinical and functional outcomes demonstrated at six months in our original cohort were sustained at three years, with no significant differences between AP and MBT tibial components [1]. These findings support AP tibial components as a comparable, cost-effective alternative in primary TKA, particularly in resource-constrained settings.