Trabecular metal tibia still stable at 5 years: An RSA study of 36 patients aged less than 60 years

BACKGROUND AND PURPOSE: Clinical results of total knee replacement (TKR) are inferior in younger patients, mainly due to aseptic loosening. Coating of components with trabecular metal (TM) is a new way of enhancing fixation to bone. We have previously reported stabilization of TM tibial components at 2 years. We now report the 5-year follow-up of these patients, including RSA of their TM tibial components. PATIENTS AND METHODS: 22 patients (26 knees) received an uncemented TM cruciate-retaining tibial component and 19 patients (21 knees) a cemented NexGen Option cruciate-retaining tibial component. Follow-up with RSA, and clinical and radiographic examinations were done at 5 years. In bilaterally operated patients, the statistical analyses included only the first-operated knee. RESULTS: Both groups had most migration within the first 3 months, the TM implants to a greater extent than the cemented implants. After 3 months, both groups stabilized and remained stable up to the 5-year follow-up. INTERPRETATION: After a high initial degree of migration, the TM tibia stabilized. This stabilization lasted for at least 5 years, which suggests a good long-term performance regarding fixation. The cemented NexGen CR tibial components showed some migration in the first 3 months and then stabilized up to the 5-year follow-up. This has not been reported previously.