Abstract
Background
Roentgen Stereophotogrammetric Analysis (RSA) represents nowadays an excellent solution for high-accuracy fixation measurement of UKAs. To date, to the best of our knowledge, no previous study has investigated long-term micromotions of a UKA using RSA. For this reason, the main purpose of the present study is to determine long-term implant fixation of 15 UKAs with all-poly tibial component using RSA at a mean 10-years follow-up. The secondary purpose was to investigate whether the progressive loss of implant's fixation correlates with a reduction of KSS scores.
Methods
Fifteen non-consecutive patients with primary knee osteoarthritis received a UKA with an all-poly tibial component between January 1995 and April 2003 in the Authors' institution. Pre and post-operative KSS scores were recorded. RSA evaluation was performed on day 2 after surgery, than at 3, 6, and 12 months and yearly thereafter. The patients were evaluated with a mean follow-up of 10 years.
Results
An increase of MTPM (Maximum Total Point Motion) values from 6 months to 1 year post-operatively was found respect to post-operative reference. Implants' displacement values were always less than 2 mm during the first 6 months, than two different trends were noticed in revised and non-revised implants. A linear and inverse correlation with statistical significance was found between MTPM and both clinical and functional KSS scores.
Conclusion
Also in a long term follow up evaluation, RSA is an effective tool to predict functional results after an all-poly UKA.
