Migration of Cemented and Uncemented Implants in Total Knee Arthroplasty with an Asymmetrical Tibial Component: A Randomized Controlled Trial with a 2-Year Model-Based Radiostereometric Analysis Follow-up.

BACKGROUND Aseptic loosening remains a main complication following total knee arthroplasty (TKA), requiring revision surgery. Radiostereometric analysis (RSA) can assess the risk of aseptic loosening. This study evaluated the migration and segmental motion of cemented and uncemented femoral and asymmetrical tibial Persona components (Zimmer Biomet) with model-based RSA. METHODS We conducted a randomized controlled trial with 63 patients (22 male patients and 41 female patients, with a mean age of 62 years) and compared patients who underwent TKA with cemented and uncemented Persona components. The primary outcome measure was the maximal total point motion (MTPM) after 2 years. The Mann-Whitney U test was used to compare groups. Migration was visualized by plotting the mean and 95% confidence interval (CI). RESULTS After 3 months, femoral components demonstrated an MTPM of 0.41 mm (95% CI, 0.35 to 0.48 mm) in the cemented group and 0.65 mm (95% CI, 0.50 to 0.80 mm) in the uncemented group. Subsequently, a stabilization occurred, and the MTPM after 24 months was 0.51 mm (95% CI, 0.41 to 0.61 mm) in the cemented group and 0.83 mm (95% CI, 0.65 to 1.02 mm) in the uncemented group. There was a significant difference between fixation types at 3 months (p = 0.04), 6 months (p = 0.03), 12 months (p = 0.02), and 24 months (p = 0.02). At 3 months postoperatively, the tibial component demonstrated an MTPM of 0.70 mm (95% CI, 0.53 to 0.88 mm) in the cemented group and 0.76 mm (95% CI, 0.61 to 0.91 mm) in the uncemented group. A stabilization was then observed, and migration after 24 months was 0.72 mm (95% CI, 0.55 to 0.89 mm) for cemented components and 0.78 mm (95% CI, 0.64 to 0.92) for uncemented components. CONCLUSIONS TKA with cemented and uncemented Persona components showed migration values within acceptable ranges, suggesting successful long-term fixation; however, significant differences in mean MTPM between cemented and uncemented femoral components were found. LEVEL OF EVIDENCE Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.