The purpose of this study was to evaluate implant migration of the fixed-bearing Sigma
A prospective radiostereometric cohort study was performed. Forty-five patients with medial OA of the knee were included and received a cemented Sigma
No significant differences in migration were found for the femoral component. For the tibial component, a difference of 0.05 mm was shown for translation on the x-axis between 4 months and 12 (p < 0.01) and between 4 months and 24 months (p < 0.01). A difference of - 0.23 to - 0.50° was shown for rotation around the x-axis (p < 0.01) and a difference of - 0.11° was shown for rotation around the z-axis between 4 and 12 months (p = 0.02). These differences in migration over time were small and fall within the clinical precision of the measurements. Tibial components were divided into a stable group (N = 26) and a continuously migrating group (N = 11), which showed a significant difference in maximal total point motion (MTPM) (p < 0.01). The Oxford knee score improved significantly from poor before surgery (23.2) to good at follow-up (37.5-40.9).
II.
The Sigma