Migration characteristics of the Profix all-polyethylene tibial component in patients with osteoarthritis aged 18-60

All-Polyethylene Tibial Components In Young Patients Have Stable Fixation; A comparison RSA Study Abstract All-polyethylene (AP) tibial components in patients aged greater than 60 years have stable tibial migration patterns and favorable survival rates when compared to identical Metal-backed (MB) designs. Tibial component migration in younger patients has not been reported. The aim of this study was to examine the migration characteristics of patients aged less than 60 years compared to a previous cohort of AP and MB tibial components of identical design in older patients. Methods A prospective consecutive study examined tibial component migration in 21 patients aged less than 60 years undergoing a cemented total knee arthroplasty with an AP tibial component by radiostereometric analysis (RSA) to 24 months. Results were compared to the authors previous series of 21 patients aged greater than 60 years that were randomized to either an AP or MB tibial component. The articulating geometry and stem design of the implants were identical as were the operative technique and post-operative regime. Results Both age groups of patients implanted with an AP component had stable migration patterns with no patient having greater than 0.2 degree rotation or 0.2mm maximum total point motion. Five of 11 MB tibial components displayed continued migration between 1 and 2 years. Subsidence was similar in all groups, maximum total point motion was greater for the MB cohort (0.34mm, 0.33mm, 0.61mm; AP<60, AP>60, MB) . Conclusions Young patients implanted with an AP tibial component had stable tibial migration patterns comparable to older patients with the same AP implant. Regardless of age, AP tibial components were at least as stable as MB tibial components.